LT®3021 very dropout voltage (VLDOTM) linear regulator that operates f
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LT3021/LT3021-1.2/ LT3021-1.5/LT3021-1.8 500mA, Voltage, Very Dropout Linear Regulator DESCRIPTION
LT®3021 very dropout voltage (VLDOTM) linear regulator that operates from input supplies down 0.9V. This device supplies 500mA output current with typical dropout voltage 160mV. LT3021 ideal input voltage output voltage applications, providing comparable electrical efficiency that switching regulator. LT3021 regulator optimizes stability transient response with ESR, ceramic output capacitors small 3.3F Other LT3021 features include 0.05% typical line regulation 0.2% typical load regulation. shutdown, quiescent current typically drops Internal protection circuitry includes reverse-battery protection, current limiting, thermal limiting with hysteresis, reverse-current protection. LT3021 available adjustable output device with output range down 200mV reference. Three fixed output voltages, 1.2V, 1.5V 1.8V, also available. LT3021 regulator available profile (0.75mm) 16-pin (5mm 5mm) package with exposed 8-lead package.
Lare registered trademarks Linear Technology Corporation. VLDO trademark Linear Technology Corporation. other trademarks property their respective owners.
Range: 0.9V Dropout Voltage: 160mV Typical Output Current: 500mA Adjustable Output (VREF VOUT(MIN) 200mV) Fixed Output Voltages: 1.2V, 1.5V, 1.8V Stable with ESR, Ceramic Output Capacitors (3.3F Minimum) 0.2% Load Regulation from 500mA Quiescent Current: 120A (Typ) Typical Quiescent Current Shutdown Current Limit Protection Reverse-Battery Protection Reverse Current Thermal Limiting with Hysteresis 16-Pin (5mm 5mm) 8-Lead Packages
APPLICATIONS
Current Regulators Battery-Powered Systems Cellular Phones Pagers Wireless Modems
TYPICAL APPLICATION
Minimum Input Voltage
MINIMUM INPUT VOLTAGE 500mA
1.8V 1.5V, 500mA VLDO Regulator
1.8V 3.3F SHDN LT3021-1.5 SENSE 3.3F VOUT 1.5V 500mA
TEMPERATURE (°C)
3021 TA01
3021 TA02
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LT3021/LT3021-1.2/ LT3021-1.5/LT3021-1.8 ABSOLUTE MAXIMUM RATINGS
(Note
Voltage Voltage .±10V Input-to-Output Differential Voltage .±10V ADJ/SENSE Voltage SHDN Voltage ±10V Output Short-Circut Duration Indefinite
Operating Junction Temperature Range Grade) (Notes 40°C 125°C Storage Temperature Range 65°C 125°C 65°C 150°C Lead Temperature (Soldering, sec, 300°C
CONFIGURATION
VIEW AGND PGND SHDN SENSE AGND VIEW PGND SHDN
LT3021-ADJ PACKAGE 16-LEAD (5mm 5mm) PLASTIC TJMAX 125°C, 35°C/ 3°C/W** EXPOSED (PIN CONNECT PINS EXPOSED MUST SOLDERED *SEE APPLICATIONS INFORMATION SECTION **MEASURED JUNCTION VIEW AGND PGND SHDN
LT3021-FIXED PACKAGE 16-LEAD (5mm 5mm) PLASTIC TJMAX 125°C, 35°C/ 3°C/W** EXPOSED (PIN CONNECT PINS EXPOSED MUST SOLDERED *SEE APPLICATIONS INFORMATION SECTION **MEASURED JUNCTION VIEW SENSE AGND PGND SHDN
LT3021-ADJ PACKAGE 8-LEAD PLASTIC TJMAX 150°C, 125°C/ 40°C/W** *SEE APPLICATIONS INFORMATION SECTION **MEASURED JUNCTION
LT3021-FIXED PACKAGE 8-LEAD PLASTIC TJMAX 150°C, 125°C/ 40°C/W** *SEE APPLICATIONS INFORMATION SECTION **MEASURED JUNCTION
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LT3021/LT3021-1.2/ LT3021-1.5/LT3021-1.8 ORDER INFORMAITON
LEAD FREE FINISH LT3021EDH#PBF LT3021EDH-1.2#PBF LT3021EDH-1.5#PBF LT3021EDH-1.8#PBF LT3021ES8#PBF LT3021ES8-1.2#PBF LT3021ES8-1.5#PBF LT3021ES8-1.8#PBF LT3021IS8-1.8#PBF LEAD BASED FINISH LT3021EDH LT3021EDH-1.2 LT3021EDH-1.5 LT3021EDH-1.8 LT3021ES8 LT3021ES8-1.2 LT3021ES8-1.5 LT3021ES8-1.8 LT3021IS8-1.8 TAPE REEL LT3021EDH#TRPBF LT3021EDH-1.2#TRPBF LT3021EDH-1.5#TRPBF LT3021EDH-1.8#TRPBF LT3021ES8#TRPBF LT3021ES8-1.2#TRPBF LT3021ES8-1.5#TRPBF LT3021ES8-1.8#TRPBF LT3021IS8-1.8#TRPBF TAPE REEL LT3021EDH#TR LT3021EDH-1.2#TR LT3021EDH-1.5#TR LT3021EDH-1.8#TR LT3021ES8#TR LT3021ES8-1.2#TR LT3021ES8-1.5#TR LT3021ES8-1.8#TR LT3021IS8-1.8#TR PART MARKING* 3021 302112 302115 302118 3021 302112 302115 302118 302118 PART MARKING* 3021 302112 302115 302118 3021 302112 302115 302118 302118 PACKAGE DESCRIPTION 16-Lead (5mm 5mm) Plastic 16-Lead (5mm 5mm) Plastic 16-Lead (5mm 5mm) Plastic 16-Lead (5mm 5mm) Plastic 8-Lead Plastic 8-Lead Plastic 8-Lead Plastic 8-Lead Plastic 8-Lead Plastic PACKAGE DESCRIPTION 16-Lead (5mm 5mm) Plastic 16-Lead (5mm 5mm) Plastic 16-Lead (5mm 5mm) Plastic 16-Lead (5mm 5mm) Plastic 8-Lead Plastic 8-Lead Plastic 8-Lead Plastic 8-Lead Plastic 8-Lead Plastic TEMPERATURE RANGE -40°C 125°C -40°C 125°C -40°C 125°C -40°C 125°C -40°C 125°C -40°C 125°C -40°C 125°C -40°C 125°C -40°C 125°C TEMPERATURE RANGE -40°C 125°C -40°C 125°C -40°C 125°C -40°C 125°C -40°C 125°C -40°C 125°C -40°C 125°C -40°C 125°C -40°C 125°C
Consult Marketing parts specified with wider operating temperature ranges. *The temperature grade identified label shipping container. more information lead free part marking, http://www.linear.com/leadfree/ more information tape reel specifications,
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LT3021/LT3021-1.2/ LT3021-1.5/LT3021-1.8 ELECTRICAL CHARACTERISTICS
SYMBOL Minimum Input Voltage (Notes 5,14) Voltage (Notes Regulated Output Voltage (Note CONDITIONS ILOAD 500mA, ILOAD 500mA, 1.5V, ILOAD 1.15V 10V, ILOAD 500mA LT3021-1.2 LT3021-1.5 LT3021-1.8 Line Regulation (Note LT3021 LT3021-1.2 LT3021-1.5 LT3021-1.8 LT3021 LT3021-1.2 LT3021-1.5 LT3021-1.8 ILOAD 10mA ILOAD 10mA ILOAD 500mA ILOAD 500mA Current VOUT(NOMINAL) 0.4V (Notes Output Voltage Noise Bias Current Shutdown Threshold SHDN Current (Note Quiescent Current Shutdown Ripple Rejection (Note ILOAD ILOAD 10mA ILOAD 100mA ILOAD 500mA COUT 4.7F ILOAD 500mA, 10Hz 100kHz, VOUT 1.2V VADJ 0.2V, 1.2V (Notes VOUT VOUT VSHDN VSHDN 10V, VSHDN= LT3021 LT3021-1.2 LT3021-1.5 LT3021-1.8 Current Limit (Note Input Reverse Leakage Current Reverse Output Current (Notes VOUT VRIP 0.5VP-P, fRIPPLE 120Hz, ILOAD 500mA VOUT VRIPPLE 0.5VP-P, fRIPPLE 120Hz, ILOAD 500mA VOUT VRIPPLE 0.5VP-P, fRIPPLE 120Hz, ILOAD 500mA VOUT VRIPPLE 0.5VP-P, fRIPPLE 120Hz, ILOAD 500mA
denotes specifications which apply over full operating temperature range, otherwise specifications 25°C.
1.176 1.157 1.470 1.447 1.764 1.737 -1.75 -10.5 -15.8 -7.5
1.05 1.10 1.224 1.236 1.530 1.545 1.836 1.854 +1.75 10.5 15.8
UNITS VRMS
1.200 1.200 1.500 1.500 1.800 1.800 2.25 6.20 0.61 0.61
1.5V, ILOAD 1.5V 10V, ILOAD 500mA 1.8V, ILOAD 1.8V 10V, ILOAD 500mA 2.1V, ILOAD 2.1V 10V, ILOAD 500mA 1.15V 10V, ILOAD 1.5V 10V, ILOAD 1.8V 10V, ILOAD 2.1V 10V, ILOAD 1.15V, ILOAD 500mA 1.5V, ILOAD 500mA 1.8V, ILOAD 500mA 2.1V, ILOAD 500mA
Load Regulation (Note
Dropout Voltage (Notes
0.25
10V, VOUT VOUT(NOMINAL) 0.5V, VOUT -10V, VOUT LT3021 LT3021-1.2 LT3021-1.5 LT3021-1.8 VOUT 1.2V, VOUT 1.2V, VOUT 1.5V, VOUT 1.8V,
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LT3021/LT3021-1.2/ LT3021-1.5/LT3021-1.8 ELECTRICAL CHARACTERISTICS
denotes specifications which apply over full operating temperature range, otherwise specifications 25°C.
voltage, 0.5V output voltage. Specifications fixed output voltage devices referred output voltage. Note Dropout voltage minimum input output voltage differential needed maintain regulation specified output current. dropout output voltage equals: (VIN VDROPOUT). Note current tested with VOUT(NOMINAL) 0.4V current source load. current will increase dropout. current curves Typical Performance Characteristics section. Note Adjust bias current flows pin. Note Shutdown current flows into SHDN pin. Note Reverse output current tested with grounded forced rated output voltage. This current flows into pin. fixed voltage devices this includes current output resistor divider. Note LT3021 tested specified these conditions with external resistor divider (20k 100k) setting VOUT 1.2V. external resistor divider adds load current. Note Reverse current higher case (rated_output) VOUT VIN, because no-load recovery circuitry active this region trying restore output voltage nominal value. Note Minimum input voltage minimum voltage required control circuit regulate output voltage supply full 500mA rated current. This specification tested VOUT 0.5V. higher output voltages minimum input voltage required regulation will equal regulated output voltage VOUT plus dropout voltage.
Note Stresses beyond those listed under Absolute Maximum Ratings cause permanent damage device. Exposure Absolute Maximum Rating condition extended periods affect device reliability lifetime. Note LT3021 regulators tested specified under pulse load conditions such that LT3021E regulators 100% tested 25°C. Performance -40°C 125°C assured design, characterization correlation with statistical process controls. LT3021I regulators guaranteed over full operating junction temperature range. Note This includes overtemperature protection that intended protect device during momentary overload conditions. Junction temperature will exceed 125°C when overtemperature protection active. Continuous operation above specified maximum operating junction temperature impair device reliability. Note Maximum junction temperature limits operating conditions. regulated output voltage specification does apply possible combinations input voltage output current. Limit output current range operating maximum input voltage. Limit input voltage range operating maximum output current. Note Typically LT3021 supplies 500mA output current with input supply. guranteed minimum input voltage 500mA output current 1.10V. Note LT3021 tested specified these conditions with external resistor divider (20k 30.1k) setting VOUT 0.5V. external resistor divider adds output load current. line regulation load regulation specifications refer change 0.2V reference
TYPICAL PERFORMANCE CHARACTERISTICS
Dropout Voltage
DROPOUT VOLTAGE (mV) OUTPUT CURRENT (mA)
3021
Dropout Voltage
125°C DROPOUT VOLTAGE (mV) TEMPERATURE (°C) 50mA 10mA 100mA 250mA VOUT 1.2V 500mA MINIMUM INPUT VOLTAGE
Minimum Input Voltage
500mA
25°C
TEMPERATURE (°C)
3021
3021
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LT3021/LT3021-1.2/ LT3021-1.5/LT3021-1.8 TYPICAL PERFORMANCE CHARACTERISTICS
Voltage
VOLTAGE (mV)
Bias Current
Quiescent Current
VOUT 1.2V VSHDN TEMPERATURE (°C) VSHDN
BIAS CURRENT (nA)
QUIESCENT CURRENT TEMPERATURE (°C)
3021
TEMPERATURE (°C)
3021
3021
Output Voltage
1.23 1.22 OUTPUT VOLTAGE OUTPUT VOLTAGE 1.21 1.20 1.19 1.18 1.17 ILOAD 1.53 1.52 1.51 1.50 1.49 1.48
Output Voltage
ILOAD 1.83 1.82 OUTPUT VOLTAGE 1.81 1.80 1.79 1.78
Output Voltage
ILOAD
TEMPERATURE (°C)
1.47
TEMPERATURE (°C)
1.77
TEMPERATURE (°C)
3021
3021
3021
Quiescent Current
VOUT 1.2V 25°C QUIESCENT CURRENT (mA) VSHDN VSHDN
Quiescent Current
VOUT 1.5V 25°C VSHDN VSHDN QUIESCENT CURRENT (mA)
Quiescent Current
VOUT 1.8V 25°C VSHDN VSHDN
QUIESCENT CURRENT (mA)
INPUT VOLTAGE
INPUT VOLTAGE
INPUT VOLTAGE
3021 3021 3021
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LT3021/LT3021-1.2/ LT3021-1.5/LT3021-1.8 TYPICAL PERFORMANCE CHARACTERISTICS
Current
CURRENT (mA) 1.2k, INPUT VOLTAGE 100mA 250mA 500mA VOUT 1.2V 25°C CURRENT (mA) 100mA 1.5k, INPUT VOLTAGE 250mA 50mA 10mA 500mA
Current
VOUT 1.5V 25°C CURRENT (mA)
Current
VOUT 1.8V 25°C 500mA
50mA 10mA
250mA 50mA 10mA 100mA 1.8k, INPUT VOLTAGE
3021 3021 3021
Current ILOAD
SHDN THRESHOLD CURRENT (mA) LOAD CURRENT (mA)
3021
SHDN Threshold
TEMPERATURE (°C) SHDN INPUT CURRENT
SHDN Input Current
VSHDN
SHDN VOLTAGE
3021
3021
SHDN Input Current
SHDN INPUT CURRENT VSHDN CURRENT LIMIT TEMPERATURE (°C)
Current Limit
VOUT REVERSE OUTPUT CURRENT
Reverse Output Current
VOUT 1.2V
1.7V
TEMPERATURE (°C)
TEMPERATURE (°C)
3021
3021
3021
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LT3021/LT3021-1.2/ LT3021-1.5/LT3021-1.8 TYPICAL PERFORMANCE CHARACTERISTICS
Input Ripple Rejection
INPUT RIPPLE REJECTION (dB) INPUT RIPPLE REJECTION (dB) 1.5V 50mVRMS RIPPLE VOUT 0.5V 500mA FREQUENCY (Hz) COUT 4.7F COUT LOAD REGULATION (mV) 1.5V 0.5VP-P RIPPLE 120Hz VOUT 0.5V 500mA TEMPERATURE (°C)
Input Ripple Rejection
-0.5
Load Regulation 500mA
100k
3021
-1.0 1.15V -1.5 VOUT 0.5V *LOAD REGULATION NUMBER REFERS -2.0 CHANGE 200mV REFERENCE VOLTAGE -2.5 TEMPERATURE (°C)
3021
3021
No-Load Recovery Threshold
OUTPUT NOISE SPECTRAL DENSITY (V/Hz) OUTPUT SINK CURRENT (mA) OUTPUT OVERSHOOT
3021
Output Noise Spectral Density
VOUT 1.2V 500mA COUT 4.7F
0.01
FREQUENCY (Hz)
100k
3021
Output Noise Load Current (10Hz 100kHz)
OUTPUT NOISE (VRMS) 0.01 IOUT 500mA/DIV VOUT 1.2V COUT 4.7F VOUT 50mV/DIV
Transient Response
LOAD CURRENT (mA)
3021
50s/DIV IOUT 50mA 500mA 1.5V VOUT 1.2V COUT
3021
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LT3021/LT3021-1.2/ LT3021-1.5/LT3021-1.8 FUNCTIONS
Package/S8 Package)
(Pins 4/Pin These pins supply power load. minimum output capacitor 3.3F prevent oscillations. Applications with large load transients require larger output capacitors limit peak voltage transients. Applications Information section more information output capacitance reverse output characteristics. SENSE (Pin 7/Pin Fixed Voltage Device Only): This sense point internal resistor divider. should tied directly pins best results. (Pin 7/Pin This inverting terminal error amplifier. typical input bias current 20nA flows (see curve Bias Current Temperature Typical Performance Characteristics). reference voltage 200mV (referred GND). AGND (Pin 8/Pin Ground. PGND (Pins 17/Pin Ground. SHDN (Pin 9/Pin SHDN puts LT3021 into power state. Pulling SHDN turns output off. Drive SHDN with either logic open collector/drain device with pull-up resistor. pull-up resistor supplies pull-up current open collector/
drain logic, normally several microamperes, SHDN current, typically 2.5A. unused, connect SHDN VIN. LT3021 does function SHDN connected. (Pins 14/Pin These pins supply power device. LT3021 requires bypass capacitor more than inches away from main input filter capacitor. output impedance battery rises with frequency, include bypass capacitor battery-powered circuits. bypass capacitor range 3.3F suffices. LT3021 withstands reverse voltages with respect ground pin. case reversed input, which occurs battery plugged backwards, LT3021 acts diode series with input. reverse current flows into LT3021 reverse voltage appears load. device protects itself load. EXPOSED (Pin DH16 Package Only): Ground. Solder ground. Connect directly Pins best performance. (Pins 16/Pins Connect. connect pins floated, tied tied GND.
BLOCK DIAGRAM
SHDN (9/5) SHUTDOWN
Package/S8 Package)
(12, 14/8) THERMAL SHUTDOWN CURRENT GAIN
200mV BIAS CURRENT REFERENCE GENERATOR 212mV
NO-LOAD RECOVERY
NOTE: LT3021 ADJUST (7/3) CONNECTED ADJUST PIN, EXTERNAL. LT3021-1.X (7/3) CONNECTED OUTPUT SENSE PIN, INTERNAL.
ERROR FIXED VOUT 1.2V 1.5V 1.8V 100k 130k 160k
(3,4/2) SENSE (7/3)
(7/3)
(8,10,17/4,6)
3021
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LT3021/LT3021-1.2/ LT3021-1.5/LT3021-1.8 APPLICATIONS INFORMATION
LT3021 very dropout linear regulator capable input supply operation. Devices supply 500mA output current dropout voltage typically 155mV. Quiescent current typically 120A drops shutdown. LT3021 incorporates several protection features, making ideal battery-powered systems. device protects itself against reverse-input reverse-output voltages. battery backup applications where output held backup battery when input pulled ground, LT3021 acts diode series with output which prevents reverse current flow. dual supply applications where regulator load returned negative supply, output pulled below ground much without affecting start-up normal operation. Adjustable Operation LT3021's output voltage range 0.2V 9.5V. Figure shows that output voltage ratio external resistors. device regulates output maintain voltage 200mV referenced ground. current equals 200mV/R1 current current minus bias current. bias current 20nA flows pin. formula Figure calculate output voltage. value sets resistor divider current 10A. Note that shutdown output turned divider current zero. Curves Voltage Temperature Bias Current Temperature appear Typical Performance Characteristics section.
LT3021 SHDN
3021
0.4mV VADJ 200mV. VOUT 1.5V, load regulation (1.5V/200mV) (0.4mV) Output Capacitance Transient Response LT3021's design stable with wide range output capacitors, optimized ceramic capacitors. output capacitor's affects stability, most notably with small value capacitors. minimum output capacitor 3.3F with less prevent oscillations. LT3021 voltage device, output load transient response function output capacitance. Larger values output capacitance decrease peak deviations provide improved transient response larger load current changes. output capacitor values greater than small feedforward capacitor with value 300pF across upper divider resistor Figure required. Under extremely output current conditions (ILOAD 30A) frequency small signal oscillation (200Hz/8mVP-P 1.2V output) occur. minimum load 100A recommended prevent this instability. Give extra consideration ceramic capacitors. Manufacturers make ceramic capacitors with variety dielectrics, each with different behavior across temperature applied voltage. most common dielectrics Z5U, Y5V, X7R. dielectrics provide high products small package cost, exhibit strong voltage temperature coefficients. dielectrics yield highly stable characterisitics more suitable output capacitor fractionally increased cost. dielectrics both exhibit excellent voltage coefficient characteristics. type works over larger temperature range exhibits better temperature stability whereas less expensive available higher values. Figures show voltage coefficient temperature coefficient comparisons between material. Voltage temperature coefficients only sources problems. Some ceramic capacitors have piezoelectric response. piezoelectric device generates voltage across terminals mechanical stress, similar piezoelectric accelerometer microphone works. ceramic capacitor, stress induced vibrations system thermal transients. resulting voltages produced cause appreciable
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VOUT
VOUT 200mV IADJ (R2) VADJ 200mV IADJ 20nA 25°C OUTPUT RANGE 0.2V 9.5V
Figure Adjustable Operation
Specifications output voltages greater than 200mV proportional ratio desired output voltage 200mV; (VOUT/200mV). example, load regulation output current change 500mA typically
LT3021/LT3021-1.2/ LT3021-1.5/LT3021-1.8 APPLICATIONS INFORMATION
CHANGE VALUE 1mV/DIV -100 VOUT 1.3V COUT ILOAD BIAS VOLTAGE 1ms/DIV
3021
BOTH CAPACITORS 16V, 1210 CASE SIZE,
Figure Noise Resulting from Tapping Ceramic Capacitor
3021
Figure Ceramic Capacitor Bias Characteristics
CHANGE VALUE BOTH CAPACITORS 16V, 1210 CASE SIZE, TEMPERATURE (°C)
eliminate this problem, LT3021 incorporates no-load light-load recovery circuit. This circuit voltage-controlled current sink that significantly improves light load transient response time discharging output capacitor quickly then turning off. current sink turns when output voltage exceeds nominal output voltage. current sink level then proportional overdrive above threshold maximum approximately 15mA. Consult curve Typical Performance Characteristics No-Load Recovery Threshold. external circuitry forces output above load recovery circuit's threshold, current sink turns attempt restore output voltage nominal. current sink remains until external circuitry releases output. However, external circuitry pulls output voltage above input voltage, input falls below output, LT3021 turns current sink shuts down bias current/reference generator circuitry. Thermal Considerations LT3021's power handling capability limited maximum rated junction temperature 125°C. power dissipated device comprised components: Output current multiplied input-to-output voltage differential: (IOUT)(VIN VOUT) current multiplied input voltage: (IGND)(VIN). current found examining current curves Typical Performance Characteristics. Power dissipation equal components listed above.
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-100
3021
Figure Ceramic Capacitor Temperature Characteristics
amounts noise. ceramic capacitor produced Figure trace response light tapping from pencil. Similar vibration induced behavior masquerade increased output voltage noise. No-Load/Light-Load Recovery transient load step occurs when output current changes from maximum level zero current very small load current. output voltage responds overshooting until regulator lowers amount current delivers level. regulator loop response time amount output capacitance control amount overshoot. Once regulator decreased output current, current provided resistor divider (which sets VOUT) only current remaining discharge output capacitor from level which overshot. amount time takes output voltage recover easily extends milliseconds with microamperes divider current microfarads output capacitance.
LT3021/LT3021-1.2/ LT3021-1.5/LT3021-1.8 APPLICATIONS INFORMATION
LT3021 regulator internal thermal limiting (with hysteresis) designed protect device during overload conditions. normal continuous conditions, exceed maximum junction temperature rating 125°C. Carefully consider sources thermal resistance from junction ambient including other heat sources mounted proximity LT3021. underside LT3021 package exposed metal (14mm2) from lead frame where attached. This allows heat directly transfer from junction printed circuit board metal control maximum operating junction temperature. dual-in-line arrangement allows metal extend beyond ends package topside (component side) PCB. Connect this metal PCB. multiple pins LT3021 also assist spreading heat PCB. LT3021 package fused with lead frame. This also allows heat transfer from printed circuit board metal, therefore reducing thermal resistance. Copper board stiffeners plated throughholes also used spread heat generated power devices. following tables list thermal resistance several different board sizes copper areas different packages. Measurements were taken still 3/32" FR-4 board with ounce copper.
Table Measured Thermal Resistance Package
COPPER AREA TOPSIDE* BACKSIDE 2500mm2 900mm2 225mm2 100mm2 50mm2 2500mm2 2500mm2 2500mm2 2500mm2 2500mm2 BOARD AREA 2500mm2 2500mm2 2500mm2 2500mm2 2500mm2 THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 30°C/W 35°C/W 50°C/W 55°C/W 65°C/W
Calculating Junction Temperature Example: Given output voltage 1.2V, input voltage range 1.8V ±10%, output current range 500mA, maximum ambient temperature 70°C, what will maximum junction temperature application using package? power dissipated device equal IOUT(MAX)(VIN(MAX) VOUT) IGND(VIN(MAX)) where IOUT(MAX) 500mA VIN(MAX) 1.98V IGND (IOUT 500mA, 1.98V) 10mA 500mA(1.98V 1.2V) 10mA(1.98V) 0.41W thermal resistance range 35°C/W 70°C/W depending copper area. junction temperature rise above ambient approximately equal 0.41W(52.5°C/W) 21.5°C maximum junction temperature equals maximum junction temperature rise above ambient plus maximum ambient temperature TJMAX 21.5°C 70°C 91.5°C Protection Features LT3021 incorporates several protection features that make ideal battery-powered circuits. addition normal protection features associated with monolithic regulators, such current limiting thermal limiting, device also protects against reverseinput voltages, reverse-output voltages reverse output-to-input voltages. Current limit protection thermal overload protection protect device against current overload conditions output device. normal operation, exceed junction temperature 125°C. pins device withstand reverse voltages 10V. LT3021 limits current flow less than negative voltage appears OUT. device protects both itself load against batteries that plugged backwards.
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Table Measured Thermal Resistance Package
COPPER AREA TOPSIDE* BACKSIDE 2500mm2 1000mm2 225mm2 100mm2 50mm2 2500mm2 2500mm2 2500mm2 2500mm2 2500mm2 BOARD AREA 2500mm2 2500mm2 2500mm2 2500mm2 2500mm2 THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) 70°C/W 70°C/W 78°C/W 84°C/W 96°C/W
*Device mounted topside.
LT3021/LT3021-1.2/ LT3021-1.5/LT3021-1.8 APPLICATIONS INFORMATION
LT3021 incurs damage pulled below ground. left open circuit grounded, pulled below ground 10V. current flows from pass transistor connected OUT. However, current flows (but limited resistor divider that sets output voltage. Current flows from bottom resistor divider from pin's internal clamp through resistor divider external circuitry pulling below ground. powered voltage source, sources current equal current limit capability LT3021 protects itself thermal limiting. this case, grounding SHDN turns LT3021 stops from sourcing current. LT3021 incurs damage pulled above below ground 10V. left open circuit grounded pulled above ground, acts like resistor series with clamp (one Schottky diode series with diode). acts like resistor series with Schottky diode pulled below ground. powered voltage source pulled below reference voltage, LT3021 attempts source current limit capability OUT. output voltage increases VDROPOUT with VDROPOUT whatever load current LT3021 supports. This condition potentially damage external circuitry powered LT3021 output voltage increases unregulated high voltage. powered voltage source pulled above reference voltage, situations occur. pulled slightly above reference voltage, LT3021 turns pass transistor, output current sourced output voltage decreases either voltage less. pulled above load recovery threshold, load recovery circuitry turns attempts sink current. actively pulled output voltage clamps Schottky diode above ground. Please note that behavior described above applies LT3021 only. resistor divider connected under same conditions, there will additional current. circuits where backup battery required, several different input/output conditions occur. output voltage held while input either pulled ground, pulled some intermediate voltage left open circuit. case where input grounded, there less than reverse output current. LT3021 forced below pulled above pin, input current drops less than typically. This occurs LT3021 input connected discharged (low voltage) battery either backup battery second regulator circuit holds output. state SHDN effect reverse output current pulled above Input Capacitance Stability LT3021 designed stable with minimum capacitance 3.3F placed pin. Ceramic capacitors with very used. However, cases where long wire used connect power supply input LT3021 (and also from ground LT3021 back power supply ground), value input capacitors combined with output load current 20mA greater result unstable application. This inductance wire forming tank circuit with input capacitor result LT3021 being unstable. self-inductance, isolated inductance, wire directly proportional length. However, diameter wire does have major influence self-inductance. example, self inductance 2-AWG isolated wire with diameter 0.26 about half inductance 30-AWG wire with diameter 0.01 foot 30-AWG wire 465nH self inductance. overall self-inductance wire reduced ways. divide current flowing towards LT3021 between parallel conductors flows same direction each. this case, farther wires placed apart from each other, more inductance will reduced, reduction when placed inches apart. Splitting wires basically connects equal inductors parallel. However, when placed close proximity from each other, mutual inductance added overall self inductance wires. most effective reduce overall inductance place forward return-current conductors (the wire input wire ground) very close proximity. 30-AWG wires separated 0.02 reduce overall self-inductance about one-fifth single isolated wire.
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LT3021/LT3021-1.2/ LT3021-1.5/LT3021-1.8 APPLICATIONS INFORMATION
LT3021 powered battery mounted close proximity same circuit board, 3.3F input capacitor sufficient stability. However, LT3021 powered distant supply, larger value input capacitor following guideline roughly addition 3.3F minimum) inches wire length. power supply output impedance vary, minimum input capacitance needed stabilize application also vary. Extra capacitance also placed directly output power supply; however, this will require order magnitude more capacitance opposed placing extra capacitance close proximity LT3021. Furthermore, series resistance placed between supply input LT3021 stabilize application; little will suffice.
PACKAGE DESCRIPTION
Package 16-Lead Plastic (5mm 5mm)
(Reference 05-08-1709)
5.00 ±0.10 0.70 ±0.05 0.20
0.115
0.40 0.05
5.50 ±0.05 4.10 ±0.05 3.45 ±0.05 SIDES) PACKAGE OUTLINE 5.00 ±0.10 3.45 0.10 SIDES)
MARK (SEE NOTE 0.200 0.75 ±0.05 4.10 ±0.10 SIDES) BOTTOM VIEW-EXPOSED 0.25 0.05 0.50
NOTCH
(DH16) 0204
0.25 0.05 0.50 4.10 ±0.05 SIDES) RECOMMENDED SOLDER PITCH DIMENSIONS
0.00 0.05
NOTE: DRAWING PROPOSED MADE VARIATION VERSION (WJJD-1) JEDEC PACKAGE OUTLINE MO-229 DRAWING SCALE DIMENSIONS MILLIMETERS DIMENSIONS EXPOSED BOTTOM PACKAGE INCLUDE MOLD FLASH. MOLD FLASH, PRESENT, SHALL EXCEED 0.15mm SIDE EXPOSED SHALL SOLDER PLATED SHADED AREA ONLY REFERENCE LOCATION
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LT3021/LT3021-1.2/ LT3021-1.5/LT3021-1.8 PACKAGE DESCRIPTION
Package 8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference 05-08-1610)
.045 ±.005 .050
.189 .197 (4.801 5.004) NOTE
.245
.160 ±.005 .228 .244 (5.791 6.197)
.150 .157 (3.810 3.988) NOTE
.030 ±.005 RECOMMENDED SOLDER LAYOUT
.010 .020 (0.254 0.508) .008 .010 (0.203 0.254)
.053 .069 (1.346 1.752)
.004 .010 (0.101 0.254)
.016 .050 (0.406 1.270) NOTE: DIMENSIONS
INCHES (MILLIMETERS) DRAWING SCALE THESE DIMENSIONS INCLUDE MOLD FLASH PROTRUSIONS. MOLD FLASH PROTRUSIONS SHALL EXCEED .006" (0.15mm)
.014 .019 (0.355 0.483)
.050 (1.270)
0303
3021fc
Information furnished Linear Technology Corporation believed accurate reliable. However, responsibility assumed use. Linear Technology Corporation makes representation that interconnection circuits described herein will infringe existing patent rights.
LT3021/LT3021-1.2/ LT3021-1.5/LT3021-1.8 RELATED PARTS
PART NUMBER LT1121/LT1121HV LT1129 LT1761 DESCRIPTION 150mA, Micropower LDOs 700mA, Micropower 100mA, Noise Micropower COMMENTS 4.2V 30V/36V, VOUT 3.75V 30V, 0.42V, 30A, 16A, Reverse-Battery Protection, SOT-223, Packages 4.2V 30V, VOUT 3.75V 30V, 0.4V, 50A, 16A, SOT-223, TO220-5, TSSOP20 Packages 1.8V 20V, VOUT 1.22V 20V, 0.3V, 20A, Noise: 20VRMSP-P, Stable with Ceramic Capacitor, ThinSOT Package 1.8V 20V, VOUT 1.22V 20V, 0.3V, 25A, Noise: <20VRMSP-P, Package 1.8V 20V, VOUT 1.22V 20V, 0.3V, 30A, Noise: 20VRMSP-P, Package 2.7V 20V, VOUT 1.21V 20V, 0.34V, 1mA, Noise: <40VRMSP-P, Version Stable with Ceramic Capacitors, TO220-5 Packages 1.6V 6.5V, VOUT(MIN) 1.25V, 0.09V, 35A, Noise: 30VRMS, ThinSOT Package 1.8V 20V, VOUT 1.22V 20V, 0.27V, 30A, Noise: 20VRMSP-P, Package 2.1V 20V, VOUT 1.21V 20V, 0.34V, 1mA, Noise: 40VRMSP-P, Version Stable with Ceramic Capacitors, TO220-5, SOT223, Packages 80V, VOUT 1.275V 60V, 0.3V, 30A, Noise: <100VRMSP-P, Stable with Output Capacitor, Exposed Package 0.9V 10V, VOUT 0.2V (min), 0.15V, 120A, Noise: <250VRMSP-P, Stable with 2.2F Ceramic Capacitors, DFN-8, Packages 0.9V 5.5V, VOUT 0.4V 3.6V (min), 0.05V, 54A, Stable with Ceramic Capacitors, DFN-6 Package 1.14V 3.5V (Boost Enabled), 1.14V 5.5V (with External 5V), 0.1V, 950A, Stable with Ceramic Capacitors, 10-Lead MSOP DFN-10 Packages 1.1V 10V, VOUT 1.21V 10V, External MOSFET RDS(ON), 1.4MHz Boost Converter Generates Gate Drive, SSOP16 Package
LT1762 LT1763 LT1764/LT1764A
150mA, Noise Micropower 500mA, Noise Micropower Noise, Fast Transient Response LDOs
LTC1844 LT1962 LT1963/LT1963A
150mA, Noise, Micropower VLDO 300mA, Noise Micropower 1.5A, Noise, Fast Transient Response LDOs
LT3010
50mA, High Voltage, Micropower
LT3020
100mA, Voltage
LTC3025 LTC3026
300mA, Voltage Micropower 1.5A, Input Voltage VLDO Regulator
LT3150
VIN, Fast Transient Response, VLDO Controller
3021fc
Linear Technology Corporation
(408) 432-1900 FAX: (408) 434-0507
0608 PRINTED
1630 McCarthy Blvd., Milpitas, 95035-7417
www.linear.com
LINEAR TECHNOLOGY CORPORATION 2005
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