TL7770-5, TL7770-12

DUAL POWER-SUPPLY SUPERVISORS

SLVS019F – OCTOBER 1987 – REVISED JULY 1999

8

POST OFFICE BOX 655303

APPLICATION INFORMATION

VS

10 k

Ω

1VSU

1RESIN

GND

1RESET

1RESET

VCC

1CT

To System Reset

10 k

Ω

RT

(see Note B)

CT

System Supply

Reset Input

(from system)

To System Reset

5

1

4

3

2

8

16

NOTE B: When VCC and 1VSU are connected to the same point, it is recommended that series resistance (RT) be added between thetime-delay

programming capacitor (CT) and the voltage-supervisor device terminal (1CT). The suggested RT value is given by:

R

V

*

1

, where V

When this series resistor is used, the td calculation is as follows:

t

1.3

* (6.5E * 5)

R

T

6.5

C

T

Figure 4. System Reset Controller With Undervoltage Sensing