L4989

2/10

PIN DESCRIPTION

PIN CONNECTIONS

N. (SO8)

N. (SO20)

NAME

FUNCTION

1

1

WEn

Watchdog enable input.

If high it activates the watchdog operation.

2

4

gnd

Ground reference

5,6,15,16

gnd

Ground

Connected these pins to a heat spreader ground

3

7

Res

Reset output.

It is pulled down when output voltage goes below Vo_th or

frequency at Wi is too low.

4

10

Vcr

Reset timing adjust.

A capacitor between Vcr pin and gnd, sets the reset delay time

(trd)

5

11

Vcw

Watchdog timer adjust

A capacitor between Vcw pin and gnd, sets the time response of

the watchdog monitor.

6

14

Wi

Watchdog input.

If the frequency at this input pin is too low, the Reset output is

activated.

7

17

Vo

Voltage regulator output

Block to ground with a capacitor >100nF (needed for regulator

stability)

8

20

Vs

Supply voltage

Block to ground directly at IC pin with a ceramic capacitor

2,3,8,9,12,

13,18,19

N. C.

not connected

GND

RES

1

3

2

4

6

5

7

8

D04AT515

N.C.

N.C.

GND

GND

RES

GND

N.C.

N.C.

N.C.

N.C.

GND

GND

N.C.

N.C.

1

3

2

4

5

6

7

8

9

18

17

16

15

14

12

13

11

19

10

20

D04AT516

SO8

SO20