Datasheet

LMC6953

SNVS132D –APRIL 1998–REVISED APRIL 2013

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BLOCK DIAGRAM OF THE LMC6953

** All five comparators' positive power supplies are connected to V

TRUTH TABLE

(1)

Power Failure 5V Over-Voltage 5V Under-Voltage 3.3V Over-Voltage 3.3V Under-Voltage MR RESET

Fail X X X X High Low

X Fail X X X High Low

X X Fail X X High Low

X X X Fail X High Low

X X X X Fail High Low

X X X X X Low Low

OK OK OK OK OK High High

(1) X = Don't Care

PIN DESCRIPTION

Pin Name Function

1 V

5V input supply voltage. This pin supplies power to the internal comparators. It can be connected to a capacitor

acting as a back-up battery. Otherwise, it should be shorted to the 5V pin.

2 5V 5V input supply voltage. This pin is not connected to the positive power supply of the internal comparators. It

provides input signal to the 5V window comparators as well as the power failure comparator.

3 3.3V 3.3V input supply voltage. This pin provides input signal to the 3.3V window comparators and the power failure

comparator.

4 MR Manual reset input pin. It takes 5V CMOS logic low and triggers RESET . If not used, this pin should be connected to

5 PWR―GND Ground.

6 GND This pin should be grounded at all times.

7 RESET Active low reset output. RESET holds low for 100 ms after both 5V and 3.3V powers recover, or after manual reset

signal returns to high state.

8 C

EXT

External capacitor pin. The value of C

EXT

sets the reset delay.

Product Folder Links: LMC6953