TL7700

SUPPLY-VOLTAGE SUPERVISOR

SLVS220A – JULY 1999 – REVISED NOVEMBER 1999

2

POST OFFICE BOX 655303

functional block diagram

Reference

Voltage

+

–

+

–

R

S

Q

+

–

Vs = 500 mV TYP

RESET

GND

CT

SENSE

†ICT = 15 µA TYP; Is = 2.5 µA TYP

VCC

ICT†

High:

On

IS†

Terminal Functions

TERMINAL

DESCRIPTION

NAME

NO.

DESCRIPTION

CT

1

Timing capacitor connection. This terminal sets the RESET output pulse duration (tpo). It is connected internally to a

15-

µA constant-current source. There is a limit on the switching speed of internal elements; even if CT is set to 0,

response speeds remain at approximately 5 to 10

µs. If CT is open, the device can be used as an adjustable-threshold

noninverting comparator. If CT is low, the internal output-stage comparator is active and the RESET output transistor

is on. An external voltage must not be applied to this terminal due to the internal structure of the device. Therefore, drive

the device using an open-collector transistor, FET, or 3-state buffer (in the low-level or high-impedance state).

GND

4

Ground. Keep this terminal as low impedance to reduce circuit noise.

NC

3, 6, 7

No internal connection

RESET

8

Reset output. This terminal can be connected directly to a system that resets in the active-low state. A pullup resistor

usually is required because the output is an npn open-collector transistor. An additional transistor should be connected

when the active-high reset or higher output current is required.

SENSE

2

Voltage sense. This terminal has a threshold level of 500 mV. The sense voltage and hysteresis can be set at the same

time when the two voltage-dividing resistors are connected. The reference voltage is temperature compensated to inhibit

temperature drift in the threshold voltage within the operating temperature range.

VCC

5

Power supply. This terminal is used in an operating-voltage range of 1.8 V to 40 V.