LTC2909 Linear Technology, LTC2909 Datasheet
LTC2909
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LTC2909 Summary of contents
Page 1
... The LTC 2909 is a dual input monitor intended for a variety of system monitoring applications. Polarity selection and a buffered reference output allow the LTC2909 to monitor positive and negative supplies for undervoltage (UV) and overvoltage (OV) conditions. The two inputs have a nominal 0.5V threshold, featuring tight 1.5% threshold accuracy over the entire operating temperature range. Glitch fi ...
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... Consult LTC Marketing for parts specifi ed with wider operating temperature ranges (Notes 1, 2) Operating Temperature Range LTC2909C ................................................ 0°C to 70°C LTC2909I .............................................– 40°C to 85°C Storage Temperature Range + 0.3V) DFN ....................................................– 65°C to 125°C CC TSOT-23 .............................................– ...
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... ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T (LTC2909-5), ADJ1 = ADJ2 = 0.55V, SEL = fl oating, unless otherwise noted. (Note 2) SYMBOL PARAMETER V Operating Supply Voltage CC(MIN Shunt Regulation Voltage CC(SHUNT Input Current ADJ Input Threshold RT ΔV ADJ Hysteresis (Note 4) ...
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... LTC2909 W U TYPICAL PERFOR A CE CHARACTERISTICS ADJ Threshold Voltage vs Temperature 508 506 504 502 500 498 496 494 492 – 100 –50 25 TEMPERATURE (°C) 2909 G01 REF Output Load Regulation 1.015 V = 2.5V CC 1.010 T = 125°C A 1.005 T = 25°C A 1.000 T = –40° ...
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... A ⎯ R ⎯ S ⎯ T Output Voltage ADJ1 = 0.55 ADJ2 = 0.45 SEL = OPEN 4 10k PULL- LTC2909-2.5 LTC2909-5 1 LTC2909-3 100 SUPPLY VOLTAGE, V 2909 G11 ⎯ R ⎯ S ⎯ T Pull-Down Current RST AT 150mV 0.1 RST AT 50mV ...
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... LTC2909 CTIO S (TSOT-23/DFN Package) ADJ1 (Pin 1/Pin 8): Adjustable Voltage Input 1. Input to voltage monitor comparator 1 (0.5V nominal threshold). The polarity of the input is selected by the state of the SEL pin (refer to Table 1). Tie to REF if unused (with SEL = V or Open). CC ADJ2 (Pin 2/Pin 7): Adjustable Voltage Input 2. Input to voltage monitor comparator 2 (0 ...
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... Comparator Mode Positive Polarity Input Timing V V ADJ RT t PROP 1V RST Comparator Mode Negative Polarity Input Timing V V ADJ RT t PROP 1V RST CC(UVLO RST LTC2909 www.DataSheet4U.com 6.5V TMR THREE-STATE DECODE RST GND CONTROL 2909 PROP ...
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... V above the UVLO threshold CC for the reset timeout before ⎯ R ⎯ S ⎯ released. The LTC2909 asserts the reset output during power-up, power-down and brownout conditions on any of the voltage inputs. Power-Up The LTC2909 uses proprietary low voltage drive circuitry for the ⎯ ...
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... Proper confi guration of the SEL pin and setting of the trip-points via external resistors allows for any two fault conditions to be detected. For example, the LTC2909 may monitor two supplies (positive, negative or one of each) for UV or for OV (or one UV and one OV). It may also monitor a single supply (positive or negative) for both UV and OV. Tables 2a and 2b show example confi ...
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... All three of the LTC2909 inputs (ADJ1, ADJ2, V have the same relative threshold accuracy of ±1.5% of the programmed nominal input voltage (over the full operating temperature range) ...
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... However, this hysteresis degrades the effective accuracy of the monitor and increases the range over which the system must operate. The LTC2909 therefore does not have hysteresis, except in comparator mode (see Setting the Reset Timeout). If hysteresis is desired in other modes, it may be added externally ...
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... Note that the value V should be negative for a nega- TRIP tive application. The LTC2909 can also be used to monitor a single supply for both UV and OV. This may be accomplished with three resistors, instead of the four required for two independent supplies. Confi gurations are shown in Figures 3 and 4. ...
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... If the 2μA fl owing out of the TMR pin does not charge the capacitor to the ground- sense threshold within the fi rst 200ms after supplies become good, the internal timer cycle will complete and ⎯ R ⎯ S ⎯ T will go high too soon. LTC2909 www.DataSheet4U.com 5% UV and ...
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... V are observed. The open-drain nature of the ⎯ R ⎯ S ⎯ T pin allows for wired-OR connection of several LTC2909s to monitor more than two supplies (see Typical Applications). Other logic with open- drain outputs may also connect to the ⎯ R ⎯ S ⎯ T line, allowing other logic-determined conditions to issue a reset ...
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... REF TS8 Package 8-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1637) 0.65 REF 1.22 REF 1.50 – 1.75 2.80 BSC 1.4 MIN (NOTE 4) 0.65 BSC 0.80 – 0.90 1.00 MAX 0.09 – 0.20 (NOTE 3) LTC2909 www.DataSheet4U.com R = 0.115 0.38 ± 0.10 TYP 0.56 ± 0. SIDES) PIN 1 CHAMFER OF EXPOSED PAD 4 1 (DDB8) DFN 1103 0.25 ± 0.05 0.50 BSC 2.15 ± ...
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... C BYP3 100nF P2C P2D P2E 221k 1.07M 1.15M V CC ADJ1 SEL R R REF LTC2909-2.5 P1D 10.7k 49.9k REF RST NTC THERMISTOR NTHS-1206N01 R25 = 100k ADJ2 TMR R = 10.7k AT 85° GND P1C P1E 51.1k 221k 12V, 3.3V and 2.5V UV DETECT Timing Specifi cations FAIL Pin, RST/ ⎯ ...