LM2599 SIMPLE SWITCHER Power Converter Step-Down Voltage Regulator wit
|
|
|
Top Searches for this datasheet
LM2599 SIMPLE SWITCHER Power Converter Step-Down Voltage Regulator with Features
LM2599 SIMPLE SWITCHER Power Converter Step-Down Voltage Regulator with Features
LM2599 series regulators monolithic integrated circuits that provide active functions step-down (buck) switching regulator capable driving load with excellent line load regulation These devices available fixed output voltages adjustable output version This series switching regulators similar LM2596 series with additional supervisory performance features added Requiring minimum number external components these regulators simple include internal frequency compensation improved line load specifications fixed-frequency oscillator Shutdown Soft-start error flag delay error flag output LM2599 series operates switching frequency thus allowing smaller sized filter components than what would needed with lower frequency switching regulators Available standard 7-lead TO-220 package with several different lead bend options 7-lead TO-263 Surface mount package standard series inductors (both through hole surface mount types) available from several different manufacturers optimized with LM2599 series This feature greatly simplifies design switch-mode power supplies Other features include guaranteed tolerance output voltage under conditions input voltage output load conditions oscillator frequency External shutdown included featuring typically standby current Self protection features include stage current limit output switch over temperature shutdown complete protection under fault conditions
Features
adjustable output versions Adjustable version output voltage range over line load conditions Guaranteed output current Available 7-pin TO-220 TO-263 (surface mount) Package Input voltage range fixed frequency internal oscillator Shutdown Soft-start regulation error flag Error output delay power standby mode typically High Efficiency Uses readily available standard inductors Thermal shutdown current limit protection
Applications
Simple high-efficiency step-down (buck) regulator Efficient pre-regulator linear regulators On-card switching regulators Positive Negative converter
Typical Application (Fixed Output Voltage Versions)
12582
Patent Number
SIMPLE SWITCHER Switchers Made Simple C1996 National Semiconductor Corporation registered trademarks National Semiconductor Corporation
12582
RRD-B30M66 Printed
Absolute Maximum Ratings (Note
Military Aerospace specified devices required please contact National Semiconductor Sales Office Distributors availability specifications Maximum Supply Voltage (VIN) Input Voltage (Note Delay Voltage (Note Flag Voltage Feedback Voltage Output Voltage Ground (Steady State) Power Dissipation Internally limited Storage Temperature Range Susceptibility Human Body Model (Note Lead Temperature Package Vapor Phase Infrared Package (Soldering Maximum Junction Temperature
Operating Conditions
Temperature Range Supply Voltage
LM2599-3 Electrical Characteristics Specifications with standard type face
type apply over full Operating Temperature Range Symbol Parameter Conditions
those with boldface
LM2599-3 (Note Limit (Note
Units (Limits)
SYSTEM PARAMETERS (Note Test Circuit Figure VOUT Output Voltage ILOAD Efficiency ILOAD V(min) V(max)
LM2599-5 Electrical Characteristics Specifications with standard type face
type apply over full Operating Temperature Range Symbol Parameter Conditions
those with boldface
LM2599-5 (Note Limit (Note
Units (Limits)
SYSTEM PARAMETERS (Note Test Circuit Figure VOUT Output Voltage ILOAD Efficiency ILOAD V(min) V(max)
LM2599-12 Electrical Characteristics Specifications with standard type face
type apply over full Operating Temperature Range Symbol Parameter Conditions
those with boldface
LM2599-12 (Note Limit (Note
Units (Limits)
SYSTEM PARAMETERS (Note Test Circuit Figure VOUT Output Voltage ILOAD Efficiency ILOAD V(min) V(max)
http
national
LM2599-ADJ Electrical Characteristics Specifications with standard type face
type apply over full Operating Temperature Range Symbol Parameter Conditions
those with boldface
LM2599-ADJ (Note Limit (Note
Units (Limits)
SYSTEM PARAMETERS (Note Test Circuit Figure Feedback Voltage ILOAD VOUT programmed Circuit Figure VOUT ILOAD V(min) V(max)
Efficiency
those with boldface type apply over full Operating Temperature Range Unless otherwise specified Adjustable version version ILOAD LM2599-XX Symbol Parameter Conditions (Note Limit (Note Units (Limits)
Output Voltage Versions Electrical Characteristics Specifications with standard type face
DEVICE PARAMETERS Feedback Bias Current Oscillator Frequency Adjustable Version Only (Note VSAT Saturation Voltage Duty Cycle (ON) Duty Cycle (OFF) Current Limit IOUT (Notes (Note (Note Peak Current (Notes Output Leakage Current (Notes Output Output ISTBY Operating Quiescent Current Standby Quiescent Current Thermal Resistance Open (Note (Note TO220 TO263 Package Junction Case TO220 Package Juncton Ambient (Note TO263 Package Juncton Ambient (Note TO263 Package Juncton Ambient (Note TO263 Package Juncton Ambient (Note (max) kHz(min) kHz(max) V(max) A(min) A(max) mA(max) mA(max) mA(max) mA(max)
http
national
those with boldface type apply over full Operating Temperature Range Unless otherwise specified Adjustable version version ILOAD LM2599-XX Symbol Parameter Conditions (Note Limit (Note Units (Limits)
Output Voltage Versions (Continued) Electrical Characteristics Specifications with standard type face
SHUTDOWN SOFT-START CONTROL Test Circuit Figure Shutdown Threshold Voltage Soft-start Voltage Shutdown Current Soft-start Current (Shutdown Mode) High (Soft-start Mode) VOUT Nominal Output Voltage VOUT 100% Nominal Output Voltage VSHUTDOWN VSoft-start FLAG DELAY CONTROL Test Circuit Figure Regulator Dropout Detector Threshold Voltage VFSAT Flag Output Saturation Voltage Flag Output Leakage Current Delay Threshold Voltage Delay Source Current Delay Saturation (Flag ISINK VDELAY VFLAG (Flag High (Flag OFF) VOUT Regulated VDELAY (Flag %(min) %(max) V(max) V(min) V(max) mA(max) mV(max) V(max) V(min) mA(max) mA(max)
http
national
Electrical Characteristics (Continued)
Note Absolute Maximum Ratings indicate limits beyond which damage device occur Operating Ratings indicate conditions which device intended functional guarantee specific performance limits guaranteed specifications test conditions Electrical Characteristics Note Voltage internally clamped clamp voltage exceeded limit current maximum Note human body model capacitor discharged through resistor into each Note Typical numbers represent most likely norm Note limits guaranteed room temperature (standard type face) temperature extremes (bold type face) room temperature limits 100% production tested limits temperature extremes guaranteed correlation using standard Statistical Quality Control (SQC) methods limits used calculate Average Outgoing Quality Level (AOQL) Note External components such catch diode inductor input output capacitors affect switching regulator system performance When LM2599 used shown Figure test circuit system performance will shown system parameters section Electrical Characteristics Note switching frequency reduced when second stage current limit activated amount reduction determined severity current overload Note diode inductor capacitor connected output Note Feedback removed from output connected force output transistor switch Note Feedback removed from output connected version version force output transistor switch Note Note Junction ambient thermal resistance external heat sink) package mounted TO-220 package mounted vertically with leads soldered printed circuit board with copper area approximately Note Junction ambient thermal resistance with TO-263 package soldered single sided printed circuit board with copper area Note Junction ambient thermal resistance with TO-263 package soldered single sided printed circuit board with copper area Note Junction ambient thermal resistance with TO-263 package soldered double sided printed circuit board with copper area LM2599S side board approximately copper other side board application hints this data sheet thermal model Switchers Made Simple version software
Typical Performance Characteristics (Circuit Figure
Normalized Output Voltage Line Regulation Efficiency
12582-2
12582
12582
Switch Saturation Voltage
Switch Current Limit
Dropout Voltage
12582-5
12582
12582
http
national
Typical Performance Characteristics (Circuit Figure (Continued)
Operating Quiescent Current Shutdown Quiescent Current Minimum Operating Supply Voltage
12582-8
12582
12582
Feedback Bias Current
Flag Saturation Voltage
Switching Frequency
12582-11
12582
12582
Soft-start
Shutdown Soft-start Current
Delay Current
12582-14
12582
12582
Soft-start Response
Shutdown Soft-start Threshold Voltage
12582-18
12582
http
national
Typical Performance Characteristics (Circuit Figure
Continuous Mode Switching Waveforms VOUT ILOAD COUT COUT Discontinuous Mode Switching Waveforms VOUT ILOAD COUT COUT
12582
12582
Output Voltage Inductor Current Output Ripple Voltage
Output Voltage Inductor Current Output Ripple Voltage
Horizontal Time Base
Horizontal Time Base
Load Transient Response Continuous Mode VOUT ILOAD COUT COUT
Load Transient Response Discontinuous Mode VOUT ILOAD COUT COUT
12582 12582
Output Voltage (AC) Load Pulse
Output Voltage (AC) Load Pulse
Horizontal Time Base
Horizontal Time Base
Connection Diagrams Order Information
Bent Staggered Leads Through Hole Package 7-Lead TO-220 Surface Mount Package 7-Lead TO-263
12582
12582
Order Number LM2599T-3 LM2599T-5 LM2599T-12 LM2599T-ADJ Package Number TA07B
Order Number LM2599S-3 LM2599S-5 LM2599S-12 LM2599S-ADJ Package Number TS7B
http national
Test Circuit Layout Guidelines
Fixed Output Voltage Versions
Component Values shown VOUT ILOAD COUT Aluminum Electrolytic Nichicon ``PL Series'' Aluminum Electrolytic Nichicon ``PL Series'' Schottky Rectifier 1N5825
Typical Values
CDELAY RPull
12582
Adjustable Output Voltage Versions
12582
VOUT VREF
where VREF
Application Information Section Application Information Section
Component Values shown VOUT ILOAD COUT Aluminum Electrolytic Nichicon ``PL Series'' Aluminum Electrolytic Nichicon ``PL Series'' Schottky Rectifier 1N5824
VOUT VREF
Select approximately resistor best stability
Typical Values
CDELAY RPULL
FIGURE Standard Test Circuits Layout Guides switching regulator layout very important Rapidly switching currents associated with wiring inductance generate voltage transients which cause problems minimal inductance ground loops wires indicated heavy lines should wide printed circuit traces should kept short possible best results external components should located close switcher possible using ground plane construction single point grounding open core inductors used special care must taken location positioning this type inductor Allowing inductor flux intersect sensitive feedback groundpath COUT wiring cause problems When using adjustable version special care must taken location feedback resistors associated wiring Physically locate both resistors near route wiring away from inductor especially open core type inductor (See application section more information
http
national
LM2599 Series Buck Regulator Design Procedure (Fixed Output)
PROCEDURE (Fixed Output Voltage Version) Given VOUT Regulated Output Voltage 12V) VIN(max) Maximum Input Voltage ILOAD(max) Maximum Load Current Inductor Selection (L1) Select correct inductor value selection guide from Figures (Output voltages respectively other voltages design procedure adjustable version From inductor value selection guide identify inductance region intersected Maximum Input Voltage line Maximum Load Current line Each region identified inductance value inductor code (LXX) Select appropriate inductor from four manufacturer's part numbers listed Figure Output Capacitor Selection (COUT) majority applications (Equivalent Series Resistance) electrolytic capacitors between solid tantalum capacitors between provide best results This capacitor should located close using short capacitor leads short copper traces capacitors larger than additional information section output capacitors application information section simplify capacitor selection procedure refer quick design component selection table shown Figure This table contains different input voltages output voltages load currents lists various inductors output capacitors that will provide best design solutions capacitor voltage rating electrolytic capacitors should least times greater than output voltage often much higher voltage ratings needed satisfy requirements output ripple voltage computer aided design software Switchers Made Simple (version later) Catch Diode Selection (D1) catch diode current rating must least times greater than maximum load current Also power supply design must withstand continuous output short diode should have current rating equal maximum current limit LM2599 most stressful condition this diode overload shorted output condition reverse voltage rating diode should least times maximum input voltage This diode must fast (short reverse recovery time) must located close LM2599 using short leads short printed circuit traces Because their fast switching speed forward voltage drop Schottky diodes provide best performance efficiency should first choice especially output voltage applications Ultra-fast recovery HighProcedure continued next page EXAMPLE (Fixed Output Voltage Version) Given VOUT VIN(max) ILOAD(max) Inductor Selection (L1) inductor selection guide version shown Figure From inductor value selection guide shown Figure inductance region intersected horizontal line vertical line inductor code inductance value required From table Figure line choose inductor part number from four manufacturers shown most instance both through hole surface mount inductors available Output Capacitor Selection (COUT) section output capacitors application information section From quick design component selection table shown Figure locate output voltage section load current column choose load current line that closest current needed your application this example line maximum input voltage column select line that covers input voltage needed your application this example line Continuing this line recommended inductors capacitors that will provide best overall performance capacitor list contains both through hole electrolytic surface mount tantalum capacitors from four different capacitor manufacturers recommended that both manufacturers manufacturer's series that listed table used this example aluminum electrolytic capacitors from several different manufacturers available with range numbers needed Panasonic Series Nichicon Series output capacitor voltage rating least more needed even switching grade aluminum electrolytic capacitor would exhibit approximately (see curve Figure voltage rating) This amount would result relatively high output ripple voltage reduce ripple output voltage less capacitor with higher value with higher voltage rating (lower ESR) should selected capacitor will reduce ripple voltage approximately half Catch Diode Selection (D1) Refer table shown Figure this example 1N5823 Schottky diode will provide best performance will overstressed even shorted output
Example continued next page
http
national
LM2599 Series Buck Regulator Design Procedure (Fixed Output) (Continued)
PROCEDURE (Fixed Output Voltage Version) Efficiency rectifiers also provide good results Ultra-fast recovery diodes typically have reverse recovery times less Rectifiers such IN5400 series much slow should used Input Capacitor (CIN) aluminum tantalum bypass capacitor needed between input ground prevent large voltage transients from appearing input addition current rating input capacitor should selected least load current capacitor manufacturers data sheet must checked assure that this current rating exceeded curve shown Figure shows typical current ratings several different aluminum electrolytic capacitor values This capacitor should located close using short leads voltage rating should approximately times maximum input voltage solid tantalum input capacitors used recomended that they surge current tested manufacturer caution when using ceramic capacitors input bypassing because cause severe ringing additional information section input capacitors Application Information section EXAMPLE (Fixed Output Voltage Version) Input Capacitor (CIN) important parameters Input capacitor input voltage rating current rating With nominal input voltage aluminum electrolytic capacitor with voltage rating greater than VIN) would needed next higher capacitor voltage rating current rating requirement input capacitor buck regulator approximately load current this example with load capacitor with current rating least needed curves shown Figure used select appropriate input capacitor From curves locate line note which capacitor values have current ratings greater than capacitor could used through hole design electrolytic capacitor (Panasonic series Nichicon series equivalent) would adequate other types other manufacturers capacitors used provided ripple current ratings adequate surface mount designs solid tantalum capacitors recommended series available from 593D series from Sprague both surge current tested
Conditions Output Voltage Load Current Input Voltage
Inductor Inductance (mH) Inductor
Output Capacitor Through Hole Electrolytic Panasonic Series Nichicon Series Surface Mount Tantalum Series Sprague 595D Series
FIGURE LM2599 Fixed Voltage Quick Design Component Selection Table
http national
LM2599 Series Buck Regulator Design Procedure (Adjustable Output)
PROCEDURE (Adjustable Output Voltage Version) Given VOUT Regulated Output Voltage VIN(max) Maximum Input Voltage ILOAD(max) Maximum Load Current Switching Frequency (Fixed nominal kHz) Programming Output Voltage (Selecting shown Figure following formula select appropriate resistor values VOUT VREF where VREF Select value between 240X lower resistor values minimize noise pickup sensitive feedback (For lowest temperature coefficient best stability with time metal film resistors EXAMPLE (Adjustable Output Voltage Version) Given VOUT VIN(max) ILOAD(max) Switching Frequency (Fixed nominal kHz) Programming Output Voltage (Selecting shown Figure Select Solve
closest value
VOUT
Inductor Selection (L1) Calculate inductor Volt microsecond constant from following formula
(VIN VOUT VSAT) VOUT 1000 VSAT
VOUT
Inductor Selection (L1) Calculate inductor Volt microsecond constant
1000
where VSAT internal switch saturation voltage diode forward voltage drop value from previous formula match with number vertical axis Inductor Value Selection Guide shown Figure horizontal axis select maximum load current Identify inductance region intersected value Maximum Load Current value Each region identified inductance value inductor code (LXX) Select appropriate inductor from four manufacturer's part numbers listed Figure Output Capacitor Selection (COUT) majority applications electrolytic solid tantalum capacitors between provide best results This capacitor should located close using short capacitor leads short copper traces capacitors larger than additional information section output capacitors application information section simplify capacitor selection procedure refer quick design table shown Figure This table contains different output voltages lists various output capacitors that will provide best design solutions capacitor voltage rating should least times greater than output voltage often much higher voltage ratings needed satisfy requirements needed output ripple voltage
ILOAD(max) From inductor value selection guide shown Figure inductance region intersected horizontal line vertical line inductor code From table Figure locate line select inductor part number from list manufacturers part numbers
Output Capacitor SeIection (COUT) section COUT Application Information section From quick design table shown Figure locate output voltage column From that column locate output voltage closest output voltage your application this example select line Under output capacitor section select capacitor from list through hole electrolytic surface mount tantalum types from four different capacitor manufacturers recommended that both manufacturers manufacturers series that listed table used this example through hole aluminum electrolytic capacitors from several different manufacturers available Panasonic Series Nichicon Series Example continued next page
Procedure continued next page
http
national
LM2599 Series Buck Regulator Design Procedure (Adjustable Output)
PROCEDURE (Adjustable Output Voltage Version) Feedforward Capacitor (CFF) (See Figure output voltages greater than approximately additional capacitor required compensation capacitor typically between wired parallel with output voltage setting resistor provides additional stability high output voltages input-output voltages very output capacitors such solid tantalum capacitors EXAMPLE (Adjustable Output Voltage Version) output capacitor rating least more needed this example either capacitor would work rating chosen because lower which provides lower output ripple voltage Other manufacturers other types capacitors also used provided capacitor specifications (especially ESR) closely match types listed table Refer capacitor manufacturers data sheet this information Feedforward Capacitor (CFF) table shown Figure contains feed forward capacitor values various output voltages this example capacitor needed Catch Diode Selection (D1) Refer table shown Figure Schottky diodes provide best performance this example 1N5825 Schottky diode would good choice diode rating more than adequate will overstressed even shorted output Input Capacitor (CIN) important parameters Input capacitor input voltage rating current rating With nominal input voltage aluminum electrolytic aluminum electrolytic capacitor with voltage rating greater than VIN) would needed Since next higher capacitor voltage rating capacitor should used capacitor voltage rating VIN) conservative guideline modified somewhat desired current rating requirement input capacitor buck regulator approximately load current this example with load capacitor with current rating least needed curves shown Figure used select appropriate input capacitor From curves locate line note which capacitor values have current ratings greater than Either capacitor could used through hole design electrolytic capacitor (Panasonic series Nichicon series equivalent) would adequate Other types other manufacturers capacitors used provided ripple current ratings adequate surface mount designs solid tantalum capacitors used caution must exercised with regard capacitor sure current rating (see Application Information input capacitors this data sheet) series available from 593D series from Sprague both surge current tested further simplify buck regulator design procedure National Semiconductor making available computer design software used with Simple Switcher line switching regulators Switchers Made Simple (version later) available diskette compatible computers
This capacitor type ceramic plastic silver mica (Because unstable characteristics ceramic capacitors made with material they recommended Catch Diode Selection (D1) catch diode current rating must least times greater than maximum load current Also power supply design must withstand continuous output short diode should have current rating equal maximum current limit LM2599 most stressful condition this diode overload shorted output condition reverse voltage rating diode should least times maximum input voltage This diode must fast (short reverse recovery time) must located close LM2599 using short leads short printed circuit traces Because their fast switching speed forward voltage drop Schottky diodes provide best performance efficiency should first choice especially output voltage applications Ultra-fast recovery HighEfficiency rectifiers also good choice some types with abrupt turn-off characteristic cause instability problems Ultra-fast recovery diodes typically have reverse recovery times less Rectifiers such 1N4001 series much slow should used Input Capacitor (CIN) aluminum tantalum bypass capacitor needed between input ground prevent large voltage transients from appearing input addition current rating input capacitor should selected least load current capacitor manufacturers data sheet must checked assure that this current rating exceeded curve shown Figure shows typical current ratings several different aluminum electrolytic capacitor values This capacitor should located close using short leads voltage rating should approximately times maximum input voltage solid tantalum input capacitors used recomended that they surge current tested manufacturer caution when using high dielectric constant ceramic capacitor input bypassing because cause severe ringing additional information section input capacitor application information section
http
national
LM2599 Series Buck Regulator Design Procedure (Adjustable Output)
(Continued) Through Hole Output Capacitor Output Voltage Panasonic Series Nichicon Series Feedforward Capacitor Surface Mount Output Capacitor Series Sprague 595D Series Feedforward Capacitor
FIGURE Output Capacitor Feedforward Capacitor Selection Table
LM2599 Series Buck Regulator Design Procedure
INDUCTOR VALUE SELECTION GUIDES (For Continuous Mode Operation)
12582
12582
FIGURE LM2599-3
FIGURE LM2599-5
12582
12582
FIGURE LM2599-12
FIGURE LM2599-ADJ
http
national
LM2599 Series Buck Regulator Design Procedure (Continued)
Inductance (mH) Current Schott Through Hole 67148350 67144070 67144080 67144090 67148370 67148380 67144100 67144110 67144120 67144130 67144140 67144150 67144160 67148390 67148400 67144170 67144180 67144190 67144200 67144210 67144220 67144230 67148410 67144240 67144250 67148290 67148300 Surface Mount 67148460 67144450 67144460 67144470 67148480 67148490 67144480 67144490 67144500 67144510 67144520 67144530 67144540 67148500 67148790 Renco Through Hole RL-1284-22-43 RL-5471-5 RL-5471-6 RL-5471-7 RL-1283-22-43 RL-1283-15-43 RL-5471-1 RL-5471-2 RL-5471-3 RL-5471-4 RL-5471-5 RL-5471-6 RL-5471-7 RL-1283-22-43 RL-1283-15-43 RL-5473-1 RL-5473-4 RL-5472-1 RL-5472-2 RL-5472-3 RL-5472-4 RL-5472-5 RL-5473-4 RL-5473-2 RL-5473-3 Surface Mount RL1500-22 RL1500-68 Pulse Engineering Through Hole PE-53815 PE-53821 PE-53822 PE-53823 PE-53824 PE-53825 PE-53826 PE-53827 PE-53828 PE-53829 PE-53830 PE-53831 PE-53932 PE-53933 PE-53934 PE-53935 PE-54036 PE-54037 PE-54038 PE-54039 PE-54040 PE-54041 PE-54042 PE-54043 PE-54044 Surface Mount PE-53815-S PE-53821-S PE-53822-S PE-53823-S PE-53825-S PE-53824-S PE-53826-S PE-53827-S PE-53828-S PE-53829-S PE-53830-S PE-53831-S PE-53932-S PE-53933-S PE-53934-S PE-53935-S PE-54036-S PE-54037-S PE-54038-S PE-54039-S PE-54040-S PE-54041-S PE-54042-S Coilcraft Surface Mount DO3308-223 DO3316-683 DO3316-473 DO3316-333 DO3316-223 DO3316-153 DOS022P-334 DOS022P-224 DOS022P-154 DOS022P-104 DOS022P-683 DOS022P-473 DOS022P-333 DOS022P-223 DOS022P-153
FIGURE Inductor Manufacturers Part Numbers
Coilcraft
Phone
(800) 322-2645 (708) 639-1469
1236 1236
Nichicon Corp
Phone
(708) 843-7500 (708) 843-2798 (714) 373-7857 (714) 373-7102 (803) 448-9411 (803) 448-1943 (207) 324-4140 (207) 324-7223
Coilcraft Europe
Phone
Panasonic
Phone
Pulse Engineering
Phone
(619) 674-8100 (619) 674-8262
Corp
Phone
Pulse Engineering Europe Renco Electronics
Phone Phone
Sprague Vishay
Phone
(800) 645-5828 (516) 586-5562 (612) 475-1173 (612) 475-1786
FIGURE Capacitor Manufacturers Phone Numbers
Schott Corp
Phone
FIGURE Inductor Manufacturers Phone Numbers
http national
LM2599 Series Buck Regulator Design Procedure (Continued)
Diodes Surface Mount Schottky Through Hole Diodes Surface Mount Through Hole
Ultra Fast Ultra Fast Ultra Fast Ultra Fast Schottky Schottky Schottky Recovery Recovery Recovery Recovery these diodes rated least 1N5820 SR302 MBR320 1N5821 MBR330 31DQ03 1N5822 these diodes rated least 50WQ03 these diodes rated least SR502 1N5823 SB520 these diodes rated least
SK32
30WQ03 SK33
SR503 1N5824 SB530
SK34 MBRS340 30WQ04 MURS320 30WF10
SR304 MBR340 31DQ04 SR305 MBR350 31DQ05 MUR320
50WQ04 MURS620 50WF10 50WQ05
SR504 1N5825 SB540 MUR620 HER601 SB550 50SQ080
SK35 MBRS360 more 30WQ05
FIGURE Diode Selection Table
Block Diagram
12582
FIGURE
http
national
Application Information
FUNCTIONS
This positive input supply switching regulator suitable input bypass capacitor must present this minimize voltage transients supply switching currents needed regulator Ground (Pin Circuit ground Output (Pin Internal switch voltage this switches between approximately VSAT) approximately with duty cycle VOUT minimize coupling sensitive circuitry board copper area connected this should kept minimum Feedback (Pin Senses regulated output voltage complete feedback loop Shutdown Soft-start (Pin This dual function provides following features Allows switching regulator circuit shut down using logic level signals thus dropping total input supply current approximately Adding capacitor this provides soft-start feature which minimizes startup current provides controlled ramp output voltage Error Flag (Pin Open collector output that provides signal (flag transistor when regulated output voltage drops more than from nominal output voltage start Error Flag until VOUT reaches nominal output voltage delay time determined Delay capacitor This signal used reset microprocessor power-up Delay (Pin power-up this used provide time delay between time regulated output voltage reaches nominal output voltage time error flag output goes high Special Note above three features (Shutdown Soft-start Error Flag Delay) used respective pins should left open
(Pin
Soft-start Region When voltage between regulator Softstart condition switch (Pin duty cycle initially starts very with narrow pulses gradually wider capacitor ramps towards duty cycle increases output voltage also increases controlled ramp center curve Figure input supply current requirement also starts level narrow pulses ramp controlled manner This very useful feature some switcher topologies that require large startup currents (such inverting configuration) which load down input power supply
Note lower curve shown Figure shows Soft-start region from 100% This duty cycle percentage output voltage percentage Also Soft-start voltage range negative temperature coefficient associated with Soft-start curve electrical characteristics section
Normal operation Above circuit operates standard Pulse Width Modulated switching regulator capacitor will continue charge until reaches internal clamp voltage approximately this driven from voltage source current must limited about
EXTERNAL COMPONENTS
SOFT-START CAPACITOR capacitor this provides regulator with Soft-start feature (slow start-up) When input voltage first applied regulator when Shutdown Softstart allowed high constant current (approximately begins charging this capacitor) capacitor voltage rises regulator goes through four operating regions (See bottom curve Figure Regulator Shutdown When voltage between regulator shutdown output voltage zero quiescent current approximately
Regulator output voltage zero With voltage between approximately internal regulator circuitry operating quiescent current rises approximately output voltage still zero Also threshold exceeded Soft-start capacitor charging current decreases from down approximately This decreases slope capacitor voltage ramp
12582
FIGURE Soft-start Delay Error Output
http
national
Application Information (Continued)
12582
FIGURE Timing Diagram Output DELAY CAPACITOR CDELAY Provides delay error flag output upper curve Figure also refer timing diagrams Figure capacitor this provides time delay between time regulated output voltage (when increasing value) reaches nominal output voltage time error flag output goes high constant current from delay charges delay capacitor resulting voltage ramp When this voltage reaches threshold approximately open collector error flag output power goes high This signal used indicate that regulated output reached correct voltage stabilized reason regulated output voltage drops more error output flag (Pin immediately goes (internal transistor turns delay capacitor provides very little delay regulated output dropping regulation delay time output that decreasing approximately 1000 times less than delay rising output delay capacitor delay time would approximately when output rising passes through threshold delay output dropping would only approximately RPull error flag output power collector transistor with emitter internally grounded error flag pullup resistor positive voltage needed error flag transistor rated maximum sink approximately error flag used left open FEEDFORWARD CAPACITOR (Adjustable Output Voltage Version) Feedforward Capacitor shown across Figure used when output voltage greater than when COUT very This capacitor adds lead compensation feedback loop increases phase margin better loop stability selection design procedure section output ripple large nominal output voltage) this ripple coupled feedback through feedforward capacitor cause error comparator trigger error flag this situation adding resistor series with feedforward capacitor approximately times will attenuate ripple voltage feedback INPUT CAPACITOR aluminum tantalum bypass capacitor needed between input ground must located near regulator using short leads This capacitor prevents large voltage transients from appearing input provides instantaneous current needed each time switch turns important parameters Input capacitor voltage rating current rating Because relatively high currents flowing buck regulator's input capacitor this capacitor should chosen current rating rather than capacitance voltage ratings although capacitance value voltage rating directly related current rating current rating capacitor could viewed capacitor's power rating current flowing through capacitors internal produces power which causes internal temperature capacitor rise current rating capacitor determined amount current required raise internal temperature approximately above ambient temperature ability capacitor dissipate this heat surrounding will determine amount current capacitor safely sustain Capacitors that physically large have large surface area will typically have higher current ratings given capacitor value higher voltage electrolytic capacitor will physically larger than lower voltage capacitor thus able dissipate more heat surrounding therefore will have higher current rating
http
national
Application Information (Continued)
12582-33
12582
FIGURE Current Ratings Electrolytic Capacitors (Typical) consequences operating electrolytic capacitor above current rating shortened operating life higher temperature speeds evaporation capacitor's electrolyte resulting eventual failure Selecting input capacitor requires consulting manufacturers data sheet maximum allowable ripple current maximum ambient temperature general guideline would select capacitor with ripple current rating approximately load current ambient temperatures current rating load current would good choice conservative design capacitor voltage rating must least times greater than maximum input voltage often much higher voltage capacitor needed satisfy current requirements graph shown Figure shows relationship between electrolytic capacitor value voltage rating current rated These curves were obtained from Nichicon ``PL'' series high reliability electrolytic capacitors designed switching regulator applications Other capacitor manufacturers offer similar types capacitors always check capacitor data sheet ``Standard'' electrolytic capacitors typically have much higher numbers lower current ratings typically have shorter operating lifetime Because their small size excellent performance surface mount solid tantalum capacitors often used input bypassing several precautions must observed small percentage solid tantalum capacitors short inrush current rating exceeded This happen turn when input voltage suddenly applied course higher input voltages produce higher inrush currents Several capacitor manufacturers 100% surge current testing their products minimize this potential
FIGURE Capacitor Capacitor Voltage Rating (Typical Electrolytic Capacitor) problem high turn currents expected necessary limit this current adding either some resistance inductance before tantalum capacitor select higher voltage capacitor with aluminum electrolytic capacitors ripple current rating must sized load current OUTPUT CAPACITOR COUT output capacitor required filter output provide regulator loop stability impedance Electrolytic solid tantalum capacitors designed switching regulator applications must used When selecting output capacitor important capacitor parameters Equivalent Series Resistance (ESR) ripple current rating voltage rating capacitance value output capacitor value most important parameter output capacitor requires value that upper lower limit output ripple voltage value needed This value determined maximum allowable output ripple voltage typically output voltage selected capacitor's extremely there possibility unstable feedback loop resulting oscillation output Using capacitors listed tables similar types will provide design solutions under conditions very output ripple voltage (less than required refer section Output Voltage Ripple Transients post ripple filter aluminum electrolytic capacitor's value related capacitance value voltage rating most cases higher voltage electrolytic capacitors have lower values (see Figure Often capacitors with much higher voltage ratings needed provide values required output ripple voltage
http
national
Application Information (Continued)
output capacitor many different switcher designs often satisfied with only three four different capacitor values several different voltage ratings quick design component selection tables Figures typical capacitor values voltage ratings manufacturers capacitor types Electrolytic capacitors recommended temperatures below rises dramatically cold temb much peratures typically rises curve shown Figure Solid tantalum capacitors have much better spec cold temperatures recommended temperatures below CATCH DIODE Buck regulators require diode provide return path inductor current when switch turns This must fast diode must located close LM2599 using short leads short printed circuit traces Because their very fast switching speed forward voltage drop Schottky diodes provide best performance especially output voltage applications lower) Ultra-fast recovery High-Efficiency rectifiers also good choice some types with abrupt turnoff characteristic cause instability problems Ultrafast recovery diodes typically have reverse recovery times less Rectifiers such IN5400 series much slow should used ripple voltage does require larger inductor values keep inductor current flowing continuously especially output load currents high input voltages simplify inductor selection process inductor selection guide (nomograph) designed (see Figures through This guide assumes that regulator operating continuous mode selects inductor that will allow peak-to-peak inductor ripple current certain percentage maximum design load current This peakto-peak inductor ripple current percentage fixed allowed change different design load currents selected (See Figure
12582
FIGURE (DIIND) Peak-to-Peak Inductor Ripple Current Percentage Load Current) Load Current allowing percentage inductor ripple current increase load currents inductor value size kept relatively When operating continuous mode inductor current waveform ranges from triangular sawtooth type waveform (depending input voltage) with average value this current waveform equal output load current Inductors available different styles such core toroid E-core bobbin core well different core materials such ferrites powdered iron least expensive bobbin stick core consists wire wound ferrite bobbin This type construction makes inexpensive inductor since magnetic flux completely contained within core generates more Electro-Magnetic Interference (EMl) This magnetic flux induce voltages into nearby printed circuit traces thus causing problems with both switching regulator operation nearby sensitive circuitry give incorrect scope readings because induced voltages scope probe Also section Open Core Inductors When multiple switching regulators located same board open core magnetics cause interference between more regulator circuits especially high currents torroid E-core inductor (closed magnetic structure) should used these situations inductors listed selection chart include ferrite E-core construction Schott ferrite bobbin core Renco Coilcraft powdered iron toroid Pulse Engineering
12582
FIGURE Capacitor Change Temperature INDUCTOR SELECTION switching regulators have basic modes operation continuous discontinuous difference between types relates inductor current whether flowing continuously drops zero period time normal switching cycle Each mode distinctively different operating characteristics which affect regulators performance requirements Most switcher designs will operate discontinuous mode when load current LM2599 Simple Switcher family) used both continuous discontinuous modes operation many cases preferred mode operation continuous mode offers greater output power lower peak switch inductor diode currents have lower out-
http
national
Application Information (Continued)
Exceeding inductor's maximum current rating cause inductor overheat because copper wire losses core saturate inductor begins saturate inductance decreases rapidly inductor begins look mainly resistive (the resistance winding) This cause switch current rise very rapidly force switch into cycle-by-cycle current limit thus reducing output load current This also result overheating inductor LM2599 Different inductor types have different saturation characteristics this should kept mind when selecting inductor inductor manufacturer's data sheets include current energy limits avoid inductor saturation DISCONTINUOUS MODE OPERATION selection guide chooses inductor values suitable continuous mode operation current applications high input voltages discontinuous mode design better choice would inductor that would physically smaller would need only half third inductance value needed continuous mode design peak switch inductor currents will higher discontinuous design these load currents below) maximum switch current will still less than switch current limit Discontinuous operation have voltage waveforms that considerable different than continuous design output (switch) waveform have some damped sinusoidal ringing present (See photo titled Discontinuous Mode Switching Waveforms) This ringing normal discontinuous operation caused feedback loop instabilities discontinuous operation there period time where neither switch diode conducting inductor current dropped zero During this time small amount energy circulate between inductor switch diode parasitic capacitance causing this characteristic ringing Normally this ringing problem unless amplitude becomes great enough exceed input voltage even then there very little energy present cause damage Different inductor types core materials produce different amounts this characteristic ringing Ferrite core inductors have very little core loss therefore produce most ringing higher core loss powdered iron inductors produce less ringing desired series could placed parallel with inductor dampen ringing computer aided design software Switchers Made Simple (version will provide component values continuous discontinuous modes operation OUTPUT VOLTAGE RIPPLE TRANSIENTS output voltage switching power supply operating continuous mode will contain sawtooth ripple voltage switcher frequency also contain short voltage spikes peaks sawtooth waveform output ripple voltage function inductor sawtooth ripple current output capacitor typical output ripple voltage range from approximately output voltage obtain ripple voltage output capacitor must however caution must exercised when using extremely capacitors because they affect loop stability resulting oscillation problems very output ripple voltage needed (less than post ripple filter recommended (See Figure inductance required typically between with resistance maintain good load regulation output filter capacitor also required assure good dynamic load response ripple reduction this capacitor desired because regulator feedback loop photo shown Figure shows typical output ripple voltage with without post ripple filter When observing output ripple with scope essential that short inductance scope probe ground connection used Most scope probe manufacturers provide special probe terminator which soldered onto regulator board preferable output capacitor This provides very short scope ground thus eliminating problems associated with inch ground lead normally provided with probe provides much cleaner more accurate picture ripple voltage waveform voltage spikes caused fast switching action output switch diode parasitic inductance output filter capacitor associated wiring minimize these voltage spikes output capacitor should designed switching regulator applications lead lengths must kept very short Wiring inductance stray capacitance well scope probe used evaluate these transients contribute amplitude these spikes
12582
FIGURE Peak-to-Peak Inductor Ripple Current Load Current
12582-37
FIGURE Post Ripple Filter Waveform
http
national
Application Information (Continued)
When switching regulator operating continuous mode inductor current waveform ranges from triangular sawtooth type waveform (depending input voltage) given input output voltage peak-topeak amplitude this inductor current waveform remains constant load current increases decreases entire sawtooth current waveform also rises falls average value center) this current waveform equal load current load current drops enough level bottom sawtooth current waveform will reach zero switcher will smoothly change from continuous discontinuous mode operation Most switcher designs (irregardless large inductor value will forced discontinuous output lightly loaded This perfectly acceptable mode operation switching regulator design knowing value peak-to-peak inductor ripple current (DIIND) useful determining number other circuit parameters Parameters such peak inductor peak switch current minimum load current before circuit becomes discontinuous output ripple voltage output capacitor calculated from peak-to-peak DIIND When inductor nomographs shown Figures through used select inductor value peak-to-peak inductor ripple current immediately determined curve shown Figure shows range (DIIND) that expected different load currents curve also shows peak-to-peak inductor ripple current (DIIND) changes from lower border upper border (for given load current) within inductance region upper border represents higher input voltage while lower border represents lower input voltage (see Inductor Selection Guides) These curves only correct continuous mode operation only inductor selection guides used select inductor value Consider following example VOUT maximum load current nominal varying between selection guide Figure shows that vertical line load current horizontal line input voltage intersect approximately midway between upper lower borders inductance region inductor will allow peak-to-peak inductor current (DIIND) flow that will percentage maximum load current Referring Figure follow line approximately midway into inductance region read peak-to-peak inductor ripple current (DIIND) left hand axis (approximately p-p) input voltage increases approaches upper border inductance region inductor ripple current increases Referring curve Figure seen that load current peak-topeak inductor ripple current (DIIND) with range from upper border (16V lower border (10V Once DIIND value known following formulas used calculate additional information about switching regulator circuit Peak Inductor peak switch current
LOAD
DIIND
Minimum load current before circuit becomes discontinuous Output Ripple Voltage (DIIND) (ESR COUT) COUT
Output Ripple Voltage (DVOUT) DIIND
062V
OPEN CORE INDUCTORS Another possible source increased output ripple voltage unstable operation from open core inductor Ferrite bobbin stick inductors have magnetic lines flux flowing through from bobbin other These magnetic lines flux will induce voltage into wire board copper trace that comes within inductor's magnetic field strength magnetic field orientation location copper trace magnetic field distance between copper trace inductor determine amount voltage generated copper trace Another looking this inductive coupling consider board copper trace turn transformer (secondary) with inductor winding primary Many millivolts generated copper trace located near open core inductor which cause stability problems high output ripple voltage problems unstable operation seen open core inductor used it's possible that location inductor with respect other traces problem determine this problem temporarily raise inductor away from board several inches then check circuit operation circuit operates correctly then magnetic flux from open core inductor causing problem Substituting closed core inductor such torroid E-core will correct problem re-arranging layout necessary Magnetic flux cutting device ground trace feedback trace positive negative traces output capacitor should minimized Sometimes locating trace directly beneath bobbin inductor will provide good results provided exactly center inductor (because induced voltages cancel themselves out) center direction other then problems could arise flux problems present even direction inductor winding make difference some circuits This discussion open core inductors frighten user alert user what kind problems watch when using them Open core bobbin ``stick'' inductors inexpensive simple making compact efficient inductor they used millions many different applications
http
national
Application Information (Continued)
output voltage load current ambient temperature curves Figure show LM2599T junction temperature rises above ambient temperature load different input output voltages data these curves taken with LM2599T (TO-220 package) operating buck switching regulator ambient temperature (still air) These temperature rise numbers approximate there many factors that affect these temperatures Higher ambient temperatures require more heat sinking TO-263 surface mount package designed soldered copper printed circuit board copper board heat sink this package other heat producing components such catch diode inductor board copper area that package soldered should least ideally should have more square inches 0028 copper Additional copper area improves thermal characteristics with copper areas greater than approximately only small improvements heat dissipation realized further thermal improvements needed double sided multilayer pc-board with large copper areas airflow recommended curves shown Figure show LM2599S (TO-263 package) junction temperature rise above ambient temperature with load various input output voltages This data taken with circuit operating buck switching regulator with components mounted board simulate junction temperature under actual operating conditions This curve used quick check approximate junction temperature various conditions aware that there many factors that affect junction temperature When load currents higher than used double sided multilayer pc-boards with large copper areas airflow might needed especially high ambient temperatures high output voltages best thermal performance wide copper traces generous amounts printed circuit board copper should used board layout (One exception this output (switch) which should have large areas copper Large areas copper provide best transfer heat (lower thermal resistance) surrounding moving lowers thermal resistance even further Package thermal resistance junction temperature rise numbers approximate there many factors that will affect these numbers Some these factors include board size shape thickness position location even board temperature Other factors trace width total printed circuit copper area copper thickness single- double-sided multilayer board amount solder board effectiveness board dissipate heat also depends size quantity spacing other components board well whether surrounding still moving Furthermore some these components such catch diode will heat board heat vary input voltage changes inductor depending physical size type core material resistance could either heat sink taking heat away from board could heat board
12582-38
Circuit Data Temperature Rise Curve TO-220 Package Capacitors Inductor Diode board Through hole electrolytic Through hole Renco Through hole Schottky square inches single sided copper 0028
FIGURE Junction Temperature Rise TO-220
12582-39
Circuit Data Temperature Rise Curve TO-263 Package Capacitors Inductor Diode board Surface mount tantalum molded ``D'' size Surface mount Pulse engineering Surface mount Schottky square inches single sided copper 0028
FIGURE Junction Temperature Rise TO-263 THERMAL CONSIDERATIONS LM2599 available packages 7-pin TO-220 7-pin surface mount TO-263 TO-220 package needs heat sink under most conditions size heat sink depends input voltage
http
national
Application Information (Continued)
SHUTDOWN SOFT-START circuit shown Figure standard buck regulator with load using Softstart capacitor photo Figures show effects Soft-start output voltage input current with without Soft-start capacitor reduced input current required startup very evident when comparing photos Soft-start feature reduces startup current from down delays slows down output voltage rise time
12582
12582
FIGURE Output Voltage Input Current Start-Up WITH Soft-start
FIGURE Output Voltage Input Current Start-Up WITHOUT Soft-start This reduction start current useful situations where input power source limited amount current deliver some applications Soft-start used replace undervoltage lockout delayed startup functions very slow output voltage ramp desired Soft-start capacitor made much larger Many seconds even minutes possible only shutdown feature needed Soft-start capacitor eliminated
12582
FIGURE Typical Circuit Using Shutdown Soft-start Error Flag Features
http
national
Application Information (Continued)
12582
FIGURE Inverting Regulator With Shutdown Soft-start lNVERTING REGULATOR circuit Figure converts positive input voltage negative output voltage with common ground circuit operates bootstrapping regulator's ground negative output voltage then grounding feedback regulator senses inverted output voltage regulates This example uses LM2599-5 generate output other output voltages possible selecting other output voltage versions including adjustable version Since this regulator topology produce output voltage that either greater than less than input voltage maximum output current greatly depends both input output voltage curve shown Figure provides guide amount output load current possible different input output voltage conditions maximum voltage appearing across regulator absolute input output voltage this must limited maximum this example when converting regulator would between input ground LM2599 maximum input voltage rating Inverting Regulator additional diode required this regulator configuration Diode used isolate input voltage ripple noise from coupling through capacitor output under light load conditions Also this diode isolation changes topology closely resemble buck configuration thus providing good closed loop stability Schottky diode recommended input voltages (because lower voltage drop) higher input voltages IN5400 diode could used Because differences operation inverting regulator standard design procedure used select inductor value majority designs inductor best choice Capacitor selection also narrowed down just values Using values shown Figure will provide good results majority inverting designs This type inverting regulator require relatively large amounts input current when starting even with light loads Input currents high LM2599 current limit (approximately needed more until output reaches nominal output voltage actual time depends output voltage size output capacitor Input power sources that current limited sources that deliver these currents without getting loaded down work correctly Because relatively high startup currents required inverting topology Soft-start feature shown Figure recommended Also shown Figure several shutdown methods inverting configuration With inverting configuration some level shifting required because ground regulator longer ground negative output voltage shutdown methods shown accept ground referenced shutdown signals
12582-44
FIGURE Maximum Load Current Inverting Regulator Circuit
http national
Application Information (Continued)
UNDERVOLTAGE LOCKOUT Some applications require regulator remain until input voltage reaches predetermined voltage Figure contains undervoltage lockout circuit buck configuration while Figures inverting types (only circuitry pertaining undervoltage lockout shown) Figure uses zener diode establish threshold voltage when switcher begins operating When input voltage less than zener voltage resistors hold Shutdown Soft-start keeping regulator shutdown mode input voltage exceeds zener voltage zener conducts pulling Shutdown Soft-start high allowing regulator begin switching threshold voltage undervoltage lockout feature approximately greater than zener voltage
12582
FIGURE Undervoltage Lockout With Hysteresis Inverting Regulator NEGATIVE VOLTAGE CHARGE PUMP Occasionally current negative voltage needed biasing parts circuit simple method generating negative voltage using charge pump technique switching waveform present shown Figure This unregulated negative voltage approximately equal positive input voltage (minus volts) supply output current There requirement however that there minimum load regulated positive output charge pump work correctly Also resistor required limit charging current some value less than LM2599 current limit (typically This method generating negative output voltage without additional inductor used with other members Simple Switcher Family using either buck boost topology
12582
FIGURE Undervoltage Lockout Buck Regulator Figures apply same feature inverting circuit Figure features constant threshold voltage turn turn (zener voltage plus approximately volt) hysteresis needed circuit Figure turn voltage which different than turn voltage amount hysteresis approximately equal value output voltage Since internal zener clamp needed limit current into this approximately when
12582
FIGURE Charge Pump Generating Current Negative Output Voltage
12582
FIGURE Undervoltage Lockout Without Hysteresis Inverting Regulator
http
national
Application Information (Continued)
TYPICAL THROUGH HOLE BOARD LAYOUT FIXED OUTPUT SIZE) DOUBLE SIDED Bottom Side Side (Component Side)
12582
COUT
Aluminum Electrolytic Panasonic ``HFQ Series'' Aluminum Electrolytic Panasonic ``HFQ Series'' Schottky Rectifier 1N5825 Renco Through Hole
RPULL CDELAY
7020
Thermalloy Heat Sink
http
national
Application Information (Continued)
TYPICAL THROUGH HOLE BOARD LAYOUT ADJUSTABLE OUTPUT SIZE) DOUBLE SIDED Bottom Side Side (Component Side)
12582
COUT
Aluminum Electrolytic Panasonic ``HFQ Series'' Aluminum Electrolytic Panasonic ``HFQ Series'' Schottky Rectifier 1N5825 Renco Through Hole formula Design Procedure Figure Application Information Section (CFF Section)
RPULL CDELAY
7020
Thermalloy Heat Sink
FIGURE Board Layout
http
national
http
national
Physical Dimensions inches (millimeters) unless otherwise noted
7-Lead TO-220 Bent Staggered Package Order Number LM2599T-3 LM2599T-5 LM2599T-12 LM2599T-ADJ JEDEC Package Number TA07B
http
national
LM2599 SIMPLE SWITCHER Power Converter Step-Down Voltage Regulator with Features
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
7-Lead TO-263 Bent Formed Package Order Number LM2599S-3 LM2599S-5 LM2599S-12 LM2599S-ADJ Package Number TS7B
LIFE SUPPORT POLICY NATIONAL'S PRODUCTS AUTHORIZED CRITICAL COMPONENTS LIFE SUPPORT DEVICES SYSTEMS WITHOUT EXPRESS WRITTEN APPROVAL PRESIDENT NATIONAL SEMICONDUCTOR CORPORATION used herein Life support devices systems devices systems which intended surgical implant into body support sustain life whose failure perform when properly used accordance with instructions provided labeling reasonably expected result significant injury user
National Semiconductor Corporation 1111 West Bardin Road Arlington 76017 1(800) 272-9959 1(800) 737-7018
critical component component life support device system whose failure perform reasonably expected cause failure life support device system affect safety effectiveness
http
national
National Semiconductor Europe 180-530 Email europe support Deutsch 180-530 English 180-532 Fran 180-532 Italiano 180-534
National Semiconductor Hong Kong 13th Floor Straight Block Ocean Centre Canton Tsimshatsui Kowloon Hong Kong (852) 2737-1600 (852) 2736-9960
National Semiconductor Japan 81-043-299-2308 81-043-299-2408
National does assume responsibility circuitry described circuit patent licenses implied National reserves right time without notice change said circuitry specifications
Other recent searches
WM8990-6180-CS42-M-REV1 - WM8990-6180-CS42-M-REV1 WM8990-6180-CS42-M-REV1 Datasheet
RI-90 - RI-90 RI-90 Datasheet
HDSP-2XXX - HDSP-2XXX HDSP-2XXX Datasheet
HDSP-21XX - HDSP-21XX HDSP-21XX Datasheet
-25XX - -25XX -25XX Datasheet
HDSP-211X - HDSP-211X HDSP-211X Datasheet
25XX - 25XX 25XX Datasheet
HDSP-212X - HDSP-212X HDSP-212X Datasheet
HA0075E - HA0075E HA0075E Datasheet
ETR0342-002 - ETR0342-002 ETR0342-002 Datasheet
DS2148 - DS2148 DS2148 Datasheet
2SC4805 - 2SC4805 2SC4805 Datasheet
Privacy Policy | Disclaimer
© 2012 Datasheet Archive
