LTC2901 Linear Technology, LTC2901 Datasheet
LTC2901
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LTC2901 Summary of contents
Page 1
... V an open-drain RST output, while the LTC2901-2 has a push-pull RST output. The 43 A supply current makes the LTC2901 ideal for power conscious systems and it may be configured to monitor less than four inputs. The parts are available in the 16-lead narrow SSOP package. ...
Page 2
... LTC2901 ABSOLUTE AXI U RATI GS (Notes V1, V2, V3, V4, V ..................................... – 0. RST (LTC2901-1)........................................ – 0. RST (LTC2901-2).......................... – 0.3V to (V2 + 0.3V) COMPX ....................................................... – 0. CWT, WDO .................................................. – 0. CRT, WDI ............................ – 0. REF Reference Load Current (I ) ............................ 1mA VREF V4 Input Current (–ADJ Mode) ............................. –1mA Operating Temperature Range LTC2901-1C/LTC2901-2C ...
Page 3
... WDI Note 5: The output pins RST, WDO and COMPX have internal pull-ups typically 6 A. However, external pull-up resistors may be used when faster rise times are required or for V Note 6: The push-pull RST output pin on the LTC2901-2 is actively pulled V2. LTC2901 ...
Page 4
... A OR COMPX V4 2901 F02 Figure 2. RST, WDO, COMPX V Test OL V Monitor Timing X V RTX t RST t UV 1.5V Watchdog Timing t RST LTC2901-2 RST SOURCE V3 200 A V4 2901 F03 Figure 3. Active Pull-Up RST V Test OH 2901 2901 TD2 2901is sn2901 ...
Page 5
... TEMPERATURE ( C) – ADJ Threshold Voltage vs Temperature 0.018 0.012 0.006 0 –0.006 –0.012 –0.018 – 100 –40 – TEMPERATURE ( C) LTC2901 3V Threshold Voltage vs Temperature 2.850 2.840 2.830 2.820 2.810 2.800 2.790 2.780 2.770 2.760 80 – 60 100 –40 – ...
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... LTC2901 W U TYPICAL PERFOR A CE CHARACTERISTICS I vs Temperature V1 100 – 60 –40 – 100 TEMPERATURE ( C) 2901 G09 I vs Temperature 2.5V 0 1.8V 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 – –40 – 100 TEMPERATURE ( C) 2901 G12 ...
Page 7
... Current vs V2 (COMPX and WDO Held at 0V 4.5 1.5 2 2 (V) 2901 G24 RST Pull-Up Current vs V2 (LTC2901- RT33 2 V RT30 V RT25 2.5 3 3 (V) 2901 G27 2901is sn2901 7 ...
Page 8
... Bypass this pin to ground with a 0.1 F (or greater) capacitor. All logic outputs (COMP1, COMP2, COMP3, COMP4, RST, WDO) are weakly pulled (LTC2901-1). RST is actively pulled the LTC2901-2. COMP4 (Pin 15): Comparator Output 4. Nondelayed, active high logic output with weak pull-up to V2. Pulls high when V4 is above reset threshold ...
Page 9
... TRANSITION WATCHDOG V CC DETECT TIMER CRT 8 WDI C RT LTC2901 COMP1 COMP2 COMP3 COMP4 15 V2 LTC2901 RST LTC2901 WDO 7 9 CWT C WT 2901 DB-1 2901is sn2901 RST 6 9 ...
Page 10
... Single pin programming selects input voltage monitor combinations. All four voltage inputs must be above predetermined thresholds for the reset not to be invoked. The LTC2901 will assert the reset and comparator outputs during power-up, power- down and brownout conditions on any one of the voltage inputs ...
Page 11
... Using the 25 C curve, R estimated to be approximately 40 . Assuming a 150pF load capacitance, the fall time is about 13.2ns. Although the outputs are considered to be “open-drain,” rises CC they do have a weak pull-up capability (see COMPX or RST LTC2901 ( TRIP 11.25 2150 9 ...
Page 12
... Using a 10k pull- up resistor, the rise time is reduced to 3.3 s for a 150pF load capacitance. The LTC2901-2 has an active pull- the RST output. The typical performance curve (RST Pull-Up Cur- rent vs V2 curve) demonstrates that the pull-up current is somewhat linear versus the V2 voltage and R mated to be approximately 625 ...
Page 13
... LTC2901 CRT V REF 6 11 SYSTEM RST V PG RESET 7 10 WDO GND WDI CWT LTC2901 ® operation. With an LTC2901 3.3V MONITOR V1 COMP1 COMP2 3 1 1.8V MONITOR V3 COMP3 13 15 FEEDBACK MONITOR V4 COMP4 8 6 COMMON RESET OUT WDI RST 12 7 LOW LOAD INDICATOR ...
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... TA03 5V, 3.3V, 2.5V, 1. LED LED LED 1 16 COMP3 COMP2 2 15 COMP1 COMP4 LTC2901 CRT V REF 6 11 SYSTEM RESET RST WDO GND 8 9 WDI WDI CWT C WT 2901 TA04 R3 464k 1% – –4.64V ...
Page 15
... TYP 0.008 – 0.012 (0.203 – 0.305) LTC2901 0.189 – 0.196* (4.801 – 4.978) 0.009 (0.229 REF 0.150 – 0.157** (3.810 – 3.988) ...
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... V WDO REF 11 5 2.15M V CRT GND CWT 100k C RT1 100k 1% 47nF 1N4148 1N4148 100k Q1 2N3904 www.linear.com 10k LTC2901 COMP1 14 16 2.5V MONITOR 2.5V V2 COMP2 COMP3 12V MONITOR 13 15 –2V MONITOR V4 COMP4 8 6 WDI RST COMMON RESET OUT PRESENT ...