L4979MD L4979D

2/10

Table 2. Pin Function

Figure 3. Pins Connection (Top view)

SO8

N°

SO20

N°

Pin

Name

Function

1

1

En

Enable input

If high, regulator, watchdog and reset are operating. If low, regulator, watchdog

and reset are shut down.

2

4

gnd

Ground reference

5,6,15,16

gnd

Ground

These pins are to be connected to a heat spreader electrically grounded

3

7

Res

Reset output.

It is pulled down when output voltage drops 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

Output capacitor >100nF is needed for regulator stability

8

20

Vs

Supply voltage

Supply capacitor (e.g. 200nF) is needed for regulator stability.

2, 3, 8, 9, 12,

13, 18, 19

N. C.

not connected

EN

GND

RES

VCR

VCW

WI

1

3

2

4

6

5

7

8

SO8

EN

N.C.

N.C.

GND

GND

RES

GND

N.C.

N.C.

N.C.

N.C.

WI

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

VCR

WCW

D00AT457

SO8

SO20