DESCRIPTIO Voltage Adjustable Inputs (0.5V) Accurate UVLO Provide
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LTC2919 Precision Triple/Dual Input Negative Voltage Monitor FEATURES
DESCRIPTIO
Voltage Adjustable Inputs (0.5V) Accurate UVLO Provides Third Monitor Input Open-Drain RST, OUT1 OUT2 Outputs Selectable Input Polarity Allows Negative, Monitoring Guaranteed Threshold Accuracy: ±1.5% 6.5V Shunt Regulator High Voltage Operation Quiescent Current Buffered Reference Negative Supply Offset Input Glitch Rejection Adjustable Reset Timeout Period Selectable Internal Timeout Saves Components Outputs Guaranteed With 0.5V Space Saving 10-Lead MSOP Packages
LTC2919 triple/dual input monitor intended variety system monitoring applications. Polarity selection buffered reference output allow LTC2919 monitor positive negative supplies undervoltage (UV) overvoltage (OV) conditions. adjustable inputs have nominal 0.5V threshold, featuring tight 1.5% threshold accuracy over entire operating temperature range. Glitch filtering ensures outputs operate reliably without false triggering. accurate threshold provides third input supply monitor 2.5V, 3.3V supply. independent output pins indicate status each adjustable input. third common output provides configurable reset timeout that accurate internal 200ms timer, programmed with external capacitor, disabled fast response. three-state input sets input polarity each adjustable input without requiring external components. LTC2919 provides highly versatile, precise, spaceconscious, micropower solution supply monitoring.
Lare registered trademarks Linear Technology Corporation. other trademarks property their respective owners. Protected U.S. Patents, including 6949965, 7292076.
APPLICATIO
Desktop Notebook Computers Network Servers Core, Monitor Automotive
TYPICAL APPLICATIO
3.3V UV/OV (Window) Monitor Application with 200ms Internal Timeout (3.3V Logic Out) Connection Input Polarity Combinations
453k ADJ1 10.7k ADJ2 76.8k
2919 TA01a
3.3V LTC2919-2.5 OUT1 OUT2 FAULT 0.1F
POLARITY ADJ1 ADJ2 OPEN
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LTC2919 ABSOLUTE RATI
Terminal Voltages (Note -0.3V OUT1, OUT2, -0.3V 7.5V ADJ1, ADJ2 -0.3V 7.5V TMR, SEL.-0.3V (VCC 0.3V) Terminal Currents (Note 3).±10mA IREF .±1mA
CONFIGURATION
VIEW OUT1 OUT2 ADJ1 ADJ2 OUT1 OUT2 VIEW ADJ1 ADJ2
PACKAGE 10-LEAD (3mm 2mm) PLASTIC TJMAX 150°C, 76°C/W EXPOSED (PIN LEFT OPEN TIED
ORDER INFORMATION
LEAD FREE FINISH TAPE REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC2919CDDB-2.5#PBF LTC2919CDDB-2.5#TRPBF LDGT 10-Lead (3mm 2mm) Plastic 70°C LTC2919IDDB-2.5#PBF LTC2919IDDB-2.5#TRPBF LDGT 10-Lead (3mm 2mm) Plastic -40°C 85°C LTC2919HDDB-2.5#PBF LTC2919HDDB-2.5#TRPBF LDGT 10-Lead (3mm 2mm) Plastic -40°C 125°C LTC2919CDDB-3.3#PBF LTC2919CDDB-3.3#TRPBF LDMW 10-Lead (3mm 2mm) Plastic 70°C LTC2919IDDB-3.3#PBF LTC2919IDDB-3.3#TRPBF LDMW 10-Lead (3mm 2mm) Plastic -40°C 85°C LTC2919HDDB-3.3#PBF LTC2919HDDB-3.3#TRPBF LDMW 10-Lead (3mm 2mm) Plastic -40°C 125°C LTC2919CDDB-5#PBF LTC2919CDDB-5#TRPBF LDMX 10-Lead (3mm 2mm) Plastic 70°C LTC2919IDDB-5#PBF LTC2919IDDB-5#TRPBF LDMX 10-Lead (3mm 2mm) Plastic -40°C 85°C LTC2919HDDB-5#PBF LTC2919HDDB-5#TRPBF LDMX 10-Lead (3mm 2mm) Plastic -40°C 125°C LTC2919CMS-2.5#PBF LTC2919CMS-2.5#TRPBF LTDGS 10-Lead Plastic MSOP 70°C LTC2919IMS-2.5#PBF LTC2919IMS-2.5#TRPBF LTDGS 10-Lead Plastic MSOP -40°C 85°C LTC2919HMS-2.5#PBF LTC2919HMS-2.5#TRPBF LTDGS 10-Lead Plastic MSOP -40°C 125°C LTC2919CMS-3.3#PBF LTC2919CMS-3.3#TRPBF LTDMT 10-Lead Plastic MSOP 70°C LTC2919IMS-3.3#PBF LTC2919IMS-3.3#TRPBF LTDMT 10-Lead Plastic MSOP -40°C 85°C LTC2919HMS-3.3#PBF LTC2919HMS-3.3#TRPBF LTDMT 10-Lead Plastic MSOP -40°C 125°C LTC2919CMS-5#PBF LTC2919CMS-5#TRPBF LTDMV 10-Lead Plastic MSOP 70°C LTC2919IMS-5#PBF LTC2919IMS-5#TRPBF LTDMV 10-Lead Plastic MSOP -40°C 85°C LTC2919HMS-5#PBF LTC2919HMS-5#TRPBF LTDMV 10-Lead Plastic MSOP -40°C 125°C Consult Marketing parts specified with wider operating temperature ranges. *Temperature grades identified label shipping container. Consult Marketing information non-standard lead based finish parts. more information lead free part marking, http://www.linear.com/leadfree/ more information tape reel specifications,
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(Notes
Operating Temperature Range LTC2919C 70°C LTC2919I.- 40°C 85°C LTC2919H -40°C 125°C Maximum Junction Temperature. 150°C Storage Temperature Range.- 65°C 150°C Lead Temperature (Soldering, sec) MSOP-10 300°C
PACKAGE 10-LEAD PLASTIC MSOP TJMAX 150°C, 120°C/W
LTC2919 ELECTRICAL CHARACTERISTICS
SYMBOL VCC(MIN) VCC(SHUNT) IADJ VCC(UVLO) PARAMETER Operating Supply Voltage Shunt Regulation Voltage Input Current Input Threshold
denotes specifications which apply over full operating temperature range, otherwise specifications 25°C. 2.5V (LTC2919-2.5), 3.3V (LTC2919-3.3), (LTC2919-5), ADJ1 ADJ2 0.55V, floating, unless otherwise noted. (Note
CONDITIONS RST, OUT1, OUT2 Correct State 1mA, IREF 2.175V (C-Grade, I-Grade) 2.175V (H-Grade)
505.0 507.5 10.0 2.250 2.970 4.500 1.010 1.015 -2.9 0.10 0.40 0.15 0.15 0.30
UNITS
495.0 492.5
Hysteresis (Note Input Current -10% UVLO Threshold
VADJ 0.55V (C-Grade, I-Grade) VADJ 0.55V (H-Grade) LTC2919-2.5 LTC2919-3.3 LTC2919-5 2.175V, IREF ±1mA
2.175 2.871 4.350 0.990 0.985 -1.5 0.40 0.10
2.213 2.921 4.425 1.000 1.000 -2.2 0.20 0.20 0.01 0.01 0.10
VCC(UVLO) VREF ITMR(UP) ITMR(DOWN) tRST(EXT) tRST(INT) VTMR(DIS) VTMR(DIS) VTMR(INT) VTMR(INT) tPROP
UVLO Hysteresis (Note Buffered Reference Voltage Pull-Up Current Pull-Down Current Reset Timeout Period, External Reset Timeout Period, Internal Timer Disable Voltage Timer Disable Hysteresis Timer Internal Mode Voltage Timer Internal Mode Hysteresis ADJx Comparator Propagation Delay OUTX Undervoltage Detect Output Voltage
VTMR VTMR CTMR 2.2nF VTMR VTMR Rising VTMR Falling VTMR Falling VTMR Rising ADJx Driven Beyond Threshold (VRTX) Less Than UVLO Threshold (VCC(UVLO)) 0.5V, 100A 2500A Output (C-Grade, I-Grade) Output (H-Grade)
Output Voltage High Leakage
Three-State Input Level Input Voltage High Level Input Voltage Voltage when Left Open State ISEL
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LTC2919 ELECTRICAL CHARACTERISTICS
SYMBOL ISEL(Z) ISEL PARAMETER Allowable Leakage When Open Input Current
denotes specifications which apply over full operating temperature range, otherwise specifications 25°C. 2.5V (LTC2919-2.5), 3.3V (LTC2919-3.3), (LTC2919-5), ADJ1 ADJ2 0.55V, floating, unless otherwise noted. (Note
CONDITIONS
UNITS
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 currents into pins positive; voltages referenced unless otherwise noted. Note maximum voltage limited input current. Since internal 6.5V shunt regulator, impedance supply
which exceeds exceed rated terminal current. Operation from higher voltage supplies requires series dropping resistor. Applications Information. Note Threshold voltages have hysteresis unless part comparator mode. Hysteresis one-sided, affecting only invalid-to-valid transitions. Applications Information.
TYPICAL PERFOR CHARACTERISTICS 25°C unless otherwise noted.
THRESHOLD VOLTAGE VARIATION 25°C VALUE)
Threshold Voltage Temperature
THRESHOLD VOLTAGE, (mV) TEMPERATURE (°C)
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-0.5 -1.0 -1.5
VOLTAGE, VREF
Output Load Regulation
125°C -0.2 -0.4 -0.6 -0.5 LOAD CURRENT (mA)
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VOLTAGE VARIATION 2.5V SUPPLY 25°C VALUE)
VOLTAGE, VARIATION (%OF LOAD 25°C VALUE)
150°C
150°C
QUIESCENT SUPPLY CURRENT,
2.5V
25°C
-40°C
UVLO Threshold Variation Temperature
1.015 1.010 1.005 1.000
Output Voltage Temperature
IREF
0.995 0.990
TEMPERATURE (°C)
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0.985
TEMPERATURE (°C)
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Output Line Regulation
125°C -0.2 -0.4 -0.6 SUPPLY VOLTAGE
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Quiescent Supply Current Temperature
2.5V 3.3V ADJ1 0.55V ADJ2 0.45V OPEN
IREF
25°C
-40°C
TEMPERATURE (°C)
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LTC2919 TYPICAL PERFOR CHARACTERISTICS
Propagation Delay Overdrive
PROPAGATION DELAY GLITCH PERCENTAGE PAST THRESHOLD
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RESET TIMEOUT PERIOD, tRST (ms)
RESET TIMEOUT PERIOD, tRST (ms)
Shunt Regulation Voltage Temperature
SHUNT REGULATION VOLTAGE, VCC(SHUNT) SHUNT REGULATOR VOLTAGE, VCC(SHUNT)
10mA 100A
OUTPUT VOLTAGE
TEMPERATURE (°C)
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OUT1, OUT2, Output Voltage
OUTPUT PULL-DOWN CURRENT (mA)
OUTPUT PULL-DOWN CURRENT (mA)
OUTPUT VOLTAGE
WITH PULL-UP WITH 100k PULL-UP SUPPLY VOLTAGE,
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25°C unless otherwise noted. Reset Timeout Period Temperature
EXTERNAL, CTMR 22nF INTERNAL
Reset Timeout Period Capacitance
10000
1000
CAPACITANCE, CTMR (nF)
1000
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TEMPERATURE (°C)
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Shunt Regulation Voltage Supply Current
25°C
OUT1, OUT2, Output Voltage
ADJ1 0.55V ADJ2 0.45V OPEN PULL-UP
LTC2919-2.5 LTC2919-3.3 LTC2919-5
0.01
SUPPLY CURRENT, (mA)
2919
SUPPLY VOLTAGE,
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OUT1, OUT2, Pull-Down Current
ADJ1 0.45V ADJ2 0.55V OPEN OUTPUT 150mV SUPPLY VOLTAGE,
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OUT1, OUT2, Pull-Down Current
OUTPUT 150mV
OUTPUT 50mV 0.01
0.001
OUTPUT 50mV
0.0001 SUPPLY VOLTAGE,
2919
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LTC2919 TYPICAL PERFOR CHARACTERISTICS
OUT1, OUT2, Output Sink Current
PULL-UP OUTPUT, 150°C ISEL 125°C ISEL 25°C
-40°C
OUTPUT SINK CURRENT (mA)
CTIO (MSOP/DFN Package)
(Pin Input Polarity Select Three-State Input. Connect VCC, leave unconnected open state select three possible input polarity combinations (refer Table (Pin Power Supply. Bypass this ground with 0.1F greater) capacitor. Operates direct supply input voltages Operates shunt regulator supply voltages greater than should have resistor between this supply limit input current greater than 10mA. When used without current-limiting resistor, voltage must exceed UVLO options allow used accurate third fixed -10% supply monitor. OUT1 (Pin Open-Drain Logic Output Asserts when positive polarity ADJ1 voltage below threshold negative polarity ADJ1 voltage above threshold. Requires external pull-up resistor pulled above VCC. OUT2 (Pin Open-Drain Logic Output Asserts when positive polarity ADJ2 voltage below threshold negative polarity ADJ2 voltage above threshold. Requires external pull-up resistor pulled above VCC. (Pin Open-Drain Inverted Reset Logic Output. Asserts when positive polarity input voltage below threshold negative polarity input voltage above threshold below UVLO threshold. Held timeout period after voltage inputs valid. Requires external pull-up resistor pulled above VCC. (Pin Device Ground. (Pin Buffered Reference Output. nominal reference used offset negative-monitoring applications. buffered reference source sink 1mA. reference drive capacitive load 1000pF Larger capacitance degrade transient performance. This does require bypass capacitor, recommended. Leave open unused. (Pin Reset Timeout Control. Attach external capacitor (CTMR) reset timeout period 9ms/nF leakage ceramic capacitor recom. mended timer accuracy. Capacitors larger than second timeout) recommended. Applications Information further details. Leaving this open generates minimum timeout approximately 400s. 2.2nF capacitor will generate 20ms timeout. Tying this ground will enable internal 200ms timeout. Tying this will disable reset timer part comparator mode. Signals from comparator outputs will then directly RST. ADJ2 (Pin Adjustable Voltage Input Input voltage monitor comparator (0.5V nominal threshold). polarity input selected state (refer Table unused (with Open).
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25°C unless otherwise noted. ISEL Temperature
ISEL Temperature
TEMPERATURE (°C)
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TEMPERATURE (°C)
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LTC2919 CTIO (MSOP/DFN Package)
ADJ1 (Pin 10): Adjustable Voltage Input Input voltage monitor comparator (0.5V nominal threshold). polarity input selected state (refer Table unused (with Open). Exposed (Pin Only): Exposed left unconnected. better thermal contact, trace. This trace must grounded unconnected.
BLOCK DIAGRA
DIAGRA
Positive Polarity Input Timing
VADJ tPROP tPROP tPROP tRST
THREE-STATE DECODE CONTROL CONTROL
6.5V OUT1
ADJ1
ADJUSTABLE PULSE GENERATOR
THREE-STATE DECODE
ADJ2
200ms PULSE GENERATOR
500mV
OUT2
1.000V
OPEN
CONTROL
CONTROL
CONTROL NEGATIVE POLARITY CONTROL POSITIVE POLARITY
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Negative Polarity Input Timing
VADJ
tPROP
tRST
tPROP
tPROP
UVLO Timing
VCC(UVLO) tPROP
VCC(UVLO) VCC(UVLO) tRST
NOTES: VCC(UVLO) except Comparator Mode COMPARATOR MODE, tRST tPROP.
tPROP
2919
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LTC2919 APPLICATIO ATIO
LTC2919 power, high accuracy triple/dual supply monitor with adjustable inputs accurate UVLO that monitor third supply. Reset timeout selected with external capacitor, internally generated 200ms, disabled entirely. three-state polarity select (SEL) chooses three possible polarity combinations adjustable input thresholds, described Table individual output released when corresponding input valid (above threshold configured positive polarity, below threshold configured negative polarity). Both input voltages (VADJ1 VADJ2) must valid above UVLO threshold longer than reset timeout period before released. LTC2919 asserts reset output during power-up, power-down brownout conditions voltage inputs. Power-Up LTC2919 uses proprietary voltage drive circuitry RST, OUT1 OUT2 pins which holds them with 200mV. This helps prevent indeterminate voltages from appearing outputs during power-up. applications where voltage pull-down capability important, supply which external pull-up resistor connects should same supply which powers part. Using same supply both ensures that RST, OUT1 OUT2 never float above 200mV during power-up, pull-down ability will then increase required pull-down current maintain logic increases. Once passes UVLO threshold, polarity selection timer initialization will occur. monitored input valid, corresponding will released. When both ADJ1 ADJ2 valid, appropriate timeout delay will begin, after which will released. Power-Down power-down, once drops below UVLO threshold either VADJ becomes invalid, asserts logic low. least 0.5V guarantees logic 0.15V RST.
Shunt Regulator LTC2919 contains internal 6.5V shunt regulator allow operation from high voltage supply. operate part from supply higher than must have current-limiting series resistor, RCC, supply. This resistor should sized according following equation: VS(MAX) 6.2V 10mA VS(MIN) 6.8V 200µA IREF where VS(MIN) VS(MAX) operating minimum maximum supply, IREF maximum current user expects draw from reference output. example, consider operation from automobile battery which might spike 60V. Assume that user will drawing 100A from reference. must then pick resistance between 5.4k 10.7k. When connected impedance supply, important that supply voltage never exceed shunt regulator begin draw large currents. Some supplies have nominal value sufficiently close shunt regulation voltage prevent sizing resistor according above equation. such supplies, series resistor used. Adjust Polarity Selection external connection selects polarities LTC2919 adjustable inputs. connected GND, connected left unconnected during normal operation. When left unconnected, maximum leakage allowable from ±5A. Table shows three possible selections polarity based connection.
Table Voltage Threshold Selection
ADJ1 INPUT Positive Polarity Positive Polarity Negative Polarity ADJ2 INPUT Positive Polarity Negative Polarity Negative Polarity Open Ground Note: Open open circuit driven three-state buffer high impedance state with leakage current less than
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LTC2919 APPLICATIO ATIO
user's application requires, driven using three-state buffer which satisfies VIL, leakage conditions this three-state input pin. state configures given input "negative polarity," voltage that must below trip point (0.5V nominal), corresponding output will pulled low. Conversely, given input configured "positive polarity", voltage must above trip point corresponding will assert low. Thus, "negative polarity" input used determine whether monitored negative voltage smaller absolute value than should (-UV), monitored positive voltage larger than should (+OV).
Table Possible Combinations Supply Monitoring. Example Purposes, Supplies Monitored Tolerance Connections Shown Only ADJ1, ADJ2, SEL, OUT1 OUT2. Output Pull-up Resistors Omitted Clarity.
RP2A 309k RP2B 115k ADJ1 OUT1 ADJ2 OUT2 RP1A 11.5k RP1B 13.7k (15V) (5V) RN1A 10.7k RN1B 13.3k -15V RN2A 309k
Positive
-15V RN2A 1.02M RN2B 137k ADJ1 OUT1 ADJ2 OUT2 RN1A 30.9k RN1B 11.8k (-15V) (-5V) RP1A RP2A 619k
Negative
309k -15V 1.02M ADJ1 OUT1 ADJ2 OUT2 11.5k 30.9k (15V) (-15V) 619k
Positive Negative
opposite true "positive polarity" input (-OV +UV). These polarity definitions also shown Table purposes this data sheet, negative voltage considered "undervoltage" closer ground than should (e.g., -4.3V supply). Proper configuration setting trip-points external resistors allows fault conditions detected. example, LTC2919 monitor supplies (positive, negative each) OV). also monitor single supply (positive negative) both Tables show example configurations monitoring possible combinations fault condition supply polarity.
RN2B 137k ADJ1 OUT1 ADJ2 OUT2 (-15V) (-5V)
Negative
RP2B 133k ADJ1 OUT1 ADJ2 OUT2 RP1B 13.7k (15V) (5V)
Positive
-15V 309k ADJ1 OUT1 ADJ2 OUT2 10.7k (15V) (-15V)
Positive Negative
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LTC2919 APPLICATIO ATIO
Table Possible Combinations Supply Monitoring. Example Purposes, Supplies Monitored Tolerance Connections Shown Only ADJ1, ADJ2, SEL, OUT1 OUT2. Output Pull-up Resistors Omitted Clarity.
OPEN
2.37M 10.7k 76.8k ADJ1 OUT1 ADJ2 OUT2 30.9k 4.02k -15V 1.02M ADJ1 OUT1 ADJ2 OUT2
Positive
309k -15V 309k ADJ1 OUT1 ADJ2 OUT2 11.5k 10.7k (15V) (-15V) 30.9k
Positive Negative
RP2A 309k RP2B 133k ADJ1 OUT1 ADJ2 OUT2 RP1A 11.5k RP1B 13.7k (15V) (5V)
Positive Positive
Adjust Input Trip Point trip threshold supplies monitored adjustable inputs with external resistor divider, allowing user complete control over trip point. Selection this trip voltage crucial monitoring system. power supply some tolerance band within which expected operate (e.g., ±10%). generally undesirable that supervisor issue reset when power supply inside this tolerance band. Such "nuisance" reset reduces reliability preventing system from functioning under normal conditions.
Negative
-15V 1.02M 619k ADJ1 OUT1 ADJ2 OUT2 (-15V) (15V)
Negative Positive
-15V RN2A 1.02M RN2B 137k ADJ1 OUT1 ADJ2 OUT2 RN1A 30.9k RN1B 13.3k (-15V) (-5V)
Negative Negative
prevent nuisance resets, supervisor threshold must guaranteed outside power supply tolerance band. ensure that threshold lies outside power supply tolerance range, nominal threshold must outside that range monitor's accuracy specification. three LTC2919 inputs (ADJ1, ADJ2, UVLO) have same maximum threshold accuracy ±1.5% programmed nominal input voltage (over full operating temperature range). Therefore, using LTC2919, typical threshold 11.5% below nominal input voltage level. input, threshold nominally 4.425V. With ±1.5% accuracy, trip threshold range
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LTC2919 APPLICATIO ATIO
4.425V ±75mV over temperature (i.e., below 5V). monitored system must thus operate reliably down 4.35V below over temperature. above discussion concerned only with value monitored supply. Real supplies also have relatively high frequency variations from sources such load transients, noise pickup. LTC2919 uses techniques combat spurious outputs toggling from high frequency variation. First, timeout period helps prevent high frequency variation whose frequency above tRST from appearing output. Second, propagation delay versus overdrive function filters short glitches before OUT1, OUT2 toggling pulling low. When becomes invalid, corresponding assert low. When supply recovers past valid threshold, reset timer starts (assuming disabled) does high until finishes. supply becomes invalid time during timeout period, timer resets starts fresh when supply next becomes valid. reduce sensitivity short glitches from toggling output pins, comparator outputs through lowpass filter before triggering output logic. transient input comparator needs sufficient magnitude duration pass filter before change monitor state. combination reset timeout comparator filtering prevents spurious changes output state without sacrificing threshold accuracy. further supply glitch immunity needed, user place external capacitor from input ground. resultant lowpass filter with resistor divider will further reject high frequency components supply, cost slowing monitor's response fault conditions. common solution problem spurious reset introduce hysteresis around nominal threshold. However, this hysteresis degrades effective accuracy monitor increases range over which system must operate. LTC2919 therefore does have hysteresis, except comparator mode tying VCC). hysteresis desired other modes,
added externally. Telecom UV/OV with Hysteresis Applications page example. Selecting External Resistors typical positive supply monitoring application, ADJx connects point external resistive divider between positive voltage being monitored ground, shown Figure When monitoring negative supply, ADJx connects point resistive divider between negative voltage being monitored buffered reference (REF), shown Figure
VMON ADJx
0.5V
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Figure Setting Positive Supply Trip Point
ADJx
VMON 0.5V
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Figure Setting Negative Supply Trip Point
Normally user will select desired trip voltage based their supply acceptable tolerances, value based current draw. Current used resistive divider will approximately: 0.5V 0.5V
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LTC2919 APPLICATIO ATIO
minimize errors arising from input bias minimize loading choose resistor (for positive supply monitoring) (for negative supply monitoring) range 100k. positive-monitoring application, then chosen RP1(2VTRIP negative-monitoring application: RN1(1 2VTRIP) Note that value VTRIP should negative negative application. LTC2919 also used monitor single supply both This accomplished with three resistors, instead four required independent supplies. Configurations shown Figures chosen above. given RP4, monitoring positive supply:
2VUV
monitoring negative supply with given RN4:
LOGIC OPEN DRAIN MOSFET OUT1
2VUV
ADJ1 VMON
ADJ2
LOGIC OPEN DRAIN MOSFET
OUT2
0.5V
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Figure Setting Trip Point Positive Supply
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ADJ1
LOGIC OPEN DRAIN MOSFET
OUT1
ADJ2
-VMON 0.5V
LOGIC OPEN DRAIN MOSFET
OUT2
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Figure Setting Trip Point Negative Supply
example, consider monitoring supply ±10%. this supply application: -5.575V -4.425V. Suppose wish consume about divider, 100k. then find 21.0k, 1.18M (nearest standard values have been chosen).
Monitoring/UVLO LTC2919 contains accurate third -10% undervoltage monitor pin. This monitor fixed nominal 11.5% below specified part number. standard part (LTC2919-2.5) configured monitor 2.5V supply (UVLO threshold 2.213V), versions monitor 3.3V 5.0V (UVLO 2.921V 4.425V, respectively) available. applications that need monitoring, 2.5V version should used, UVLO will simply guarantee that above minimum required proper threshold timer accuracy before timeout begins. Setting Reset Timeout
goes high after reset timeout period when inputs valid. This reset timeout configured three ways: internal 200ms, programmed external capacitor timeout (comparator mode). externally-controlled mode, connected capacitor ground. value that capacitor allows selection timeout ranging from about 400s seconds. following section details.
LTC2919 APPLICATIO ATIO
user wishes avoid having external capacitor, should tied ground, switching part internal 200ms timer. user requires shorter timeout than 400s, wishes perform application-specific processing reset output, part comparator mode tying VCC. comparator mode, timer bypassed comparator outputs straight reset output. current required hold ground about 2.2A. force from floating state ground require much 100A during transition. When part comparator mode, means preventing false reset been removed, small amount one-sided hysteresis added inputs prevent oscillation monitored voltage passes through threshold. This hysteresis such that valid-to-invalid transition threshold unchanged, invalid-to-valid threshold moved about 0.7%. Thus, when input polarity positive, threshold voltage 500mV nominal when input above 500mV. soon input drops below 500mV, threshold moves 503.5mV nominal. Conversely, when configured negative-polarity input, threshold 500mV when input below 500mV, switches 496.5mV when input goes above 500mV. comparator mode feature enabled directly shorting pin. Connecting other voltage have unpredictable results. Selecting Reset Timing Capacitor Connecting capacitor, CTMR, between ground sets reset timeout, tRST. following formula approximates value capacitor needed particular timeout: CTMR tRST [pF/ms] Leaving open with external capacitor generates reset timeout approximately 400s.
Maximum length reset timeout limited ability part charge large capacitor start-up. Initially, with large (discharged) capacitor pin, part will assume internal timer mode (since voltage will ground). 2.2A flowing does charge capacitor ground-sense threshold within first 200ms after supplies become good, internal timer cycle will complete will high soon. This imposes practical limit second timeout) length timeout during power-up needs longer than 200ms. power-up timeout important, larger capacitors used, subject limitation that capacitor leakage current must exceed 500nA, function timer will impaired. Output Pins Characteristics characteristics OUT1, OUT2 pulldown strength shown Typical Performance Characteristics section. OUT1, OUT2 opendrain pins thus require external pull-up resistors logic supply. They pulled above VCC, providing absolute maximum rating observed. noted discussion power power down, circuits that drive OUT1, OUT2 powered VCC. During fault condition, least 0.5V guarantees 0.15V. open-drain nature allows wired-OR connection several LTC2919s monitor more than supplies (see Typical Applications). Other logic with opendrain outputs also connect line, allowing other logic-determined conditions issue reset.
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LTC2919 TYPICAL APPLICATIO
Supply Undervoltage Monitor with 2.5V Reset Output 20ms Timeout
-15V 3.3V 2.5V CBYP1 100nF RPU1 RPU2 RN2A 137k ADJ1 RN2B 309k RN1A 13.3k RN1B 10.7k ADJ2 CTMR1 2.2nF OUT1 -5V_OK -15V_OK 5V_OK 15V_OK LTC2919-2.5 RPU5 RPU3 ADJ1 RP1A 13.7k RP1B 11.5k OUT1 ADJ2
2919 TA02
OUT2
RP2A 1.43M RP2A2 169k VUV(RISING): 43.3V VUV(FALLING): 38.7V VOV(RISING): 71.6V VOV(FALLING): 70.2V
FDG6301N SIMILAR
2919 TA03
MANUAL RESET PUSHBUTTON 249k -12V
SYSTEM
RPU4
CBYP2 100nF
SYSTEM_OK RP2A 115k RP2B 309k
LTC2919-3.3
OUT2
CTMR2 2.2nF
Telecom UV/OV Monitor with Hysteresis
SYSTEM RP2B 1.91M 0.25W CBYP 100nF
ADJ1 LTC2919-2.5 ADJ2 RP1A 18.7k RP1B 13.7k RP1B2 681k OUT1 OUT2
RPU3
PWRGD
RPU1 RPU2
±12V Monitor Powered from 12V, 20ms Timeout (1.8V Logic Out)
1.07M ADJ1 49.9k 10.7k CBYP 100nF 1.8V RPU3 RPU1 RPU2
10k*
LTC2919-2.5 ADJ2 OUT1
12V_OK OUT2 -12V_OK CTMR 2.2nF
2919 TA01b
*OPTIONAL
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LTC2919 PACKAGE DESCRIPTIO
Package 10-Lead Plastic (3mm 2mm)
(Reference 05-08-1722
0.64 ±0.05 SIDES) 0.70 ±0.05 2.55 ±0.05 1.15 ±0.05 PACKAGE OUTLINE 0.25 0.05 0.50 2.39 ±0.05 SIDES) RECOMMENDED SOLDER PITCH DIMENSIONS NOTE: DRAWING CONFORMS VERSION (WECD-1) JEDEC PACKAGE OUTLINE M0-229 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 BOTTOM PACKAGE MARK (SEE NOTE 2.00 ±0.10 SIDES) 0.64 0.05 SIDES) 0.25 0.05 2.39 ±0.05 SIDES) BOTTOM VIEW-EXPOSED 0.20 0.25 CHAMFER
(DDB10) 0905
3.00 ±0.10 SIDES)
0.05
0.115
0.40 0.10
0.200
0.75 ±0.05
0.50
0.05
Package 10-Lead Plastic MSOP
(Reference 05-08-1661
3.00 0.102 (.118 .004) (NOTE
0.497 0.076 (.0196 .003)
0.889 0.127 (.035 .005)
0.254 (.010) GAUGE PLANE
DETAIL
4.90 0.152 (.193 .006)
3.00 0.102 (.118 .004) (NOTE
5.23 (.206)
3.20 3.45 (.126 .136)
0.53 0.152 (.021 .006) DETAIL 0.18 (.007) SEATING PLANE 0.17 0.27 (.007 .011) 1.10 (.043) 0.86 (.034)
0.50 0.305 0.038 (.0197) (.0120 .0015) RECOMMENDED SOLDER LAYOUT
NOTE: DIMENSIONS MILLIMETER/(INCH) DRAWING SCALE DIMENSION DOES INCLUDE MOLD FLASH, PROTRUSIONS GATE BURRS. MOLD FLASH, PROTRUSIONS GATE BURRS SHALL EXCEED 0.152mm (.006") SIDE DIMENSION DOES INCLUDE INTERLEAD FLASH PROTRUSIONS. INTERLEAD FLASH PROTRUSIONS SHALL EXCEED 0.152mm (.006") SIDE LEAD COPLANARITY (BOTTOM LEADS AFTER FORMING) SHALL 0.102mm (.004")
2919f
0.50 (.0197)
0.1016 0.0508 (.004 .002)
MSOP (MS) 0307
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.
LTC2919 TYPICAL APPLICATIO
+12V
Powered from 12V, +5VOUT Sequenced Start-up First, Followed -5VOUT, with Monitor, 200ms Timeout
4.7k CBYP 0.1F LTC2919-2.5 ADJ1 13.7k 13.3k ADJ2 OUT1 OUT2 RPU2 PWRGD RPU3 SYS_RESET
DC/DC CONVERTER
137k DC/DC CONVERTER SHDN
RELATED PARTS
PART NUMBER LTC1326/LTC1326-2.5 LTC1536 LTC1540 LTC1726-2.5/LTC1726-5 LTC1727/LTC1728 LTC1985-1.8 LTC2900 LTC2901 LTC2902 LTC2903 LTC2904/LTC2905 LTC2906/LTC2907 LTC2908 LTC2909 LTC2912-LTC2914 LTC2915-LTC2918 LT6700 DESCRIPTION Micropower Precision Triple Supply Monitor 5V/2.5V, 3.3V Precision Triple Supply Monitor Applications Nanopower Comparator with Reference Micropower Triple Supply Monitor 2.5V/5V, 3.3V Micropower Triple Supply Monitor with Open-Drain Reset Micropower Triple Supply Monitor with Push-Pull Reset Output Programmable Quad Supply Monitor Programmable Quad Supply Monitor Programmable Quad Supply Monitor Precision Quad Supply Monitor 3-State Programmable Precision Dual Supply Monitor Precision Dual Supply Monitor 1-Selectable Adjustable Precision Supply Monitor (Four Fixed Adjustable) Precision, Dual Input Negative Voltage Monitor Single/Dual/Quad Voltage Monitors Single Voltage Monitor with Unique Thresholds Micropower, Voltage, Dual Comparator with 400mV Reference COMMENTS 4.725V, 3.118V, Threshold (±0.75%) Meets tFAIL Timing Specifications Adjustable Hysteresis Adjustable Reset Watchdog Time-Outs Individual Monitor Outputs MSOP/5-Lead SOT-23 5-Lead SOT-23 Package Adjustable Reset, 10-Lead MSOP 10-Lead Package Adjustable Reset Watchdog Timer, 16-Lead SSOP Package Adjustable Reset Tolerance, 16-Lead SSOP Package, Margining Functions 6-Lead SOT-23 Package, Ultralow Voltage Reset Adjustable Tolerance Reset Timer, 8-Lead SOT-23 Package Separate Pin, RST/RST Outputs/Adjustable Reset Timer 8-Lead SOT-23 Packages 8-Lead SOT-23 Packages Separate Pin, Adjustable Reset Timer, H-Grade Temperature Range Manual Reset, Watchdog, TSOT-8/MSOP-10 Package, H-Grade Temperature Range 6-Lead SOT-23 Package
2919f
Linear Technology Corporation
(408) 432-1900 FAX: (408) 434-0507
1630 McCarthy Blvd., Milpitas, 95035-7417
www.linear.com
LINEAR TECHNOLOGY CORPORATION 2008
115k
2919 TA06
0208 PRINTED
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