DS8714 Rev 3

5/19

L4989D, L4989MD

Block diagram and pin configuration

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1

Block diagram and pin configuration

Figure 1. Block diagram

Table 2. Pins description

Pin name

SO-8(D)

S0-20(MD)

Function

WEn

11

Watchdog Enable input

If high watchdog functionality is active.

Gnd

2

4

Ground reference

Gnd

5, 6, 15, 16

Ground.

Connected these pins to a heat spreader ground

Res

3

7

Reset output.

It is pulled down when output voltage goes below Vo_th or

frequency at Wi is too low.

Vcr

4

10

Reset timing adjust.

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

(trd)

Vcw

5

11

Watchdog timer adjust

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

the watchdog monitor.

Wi

6

14

Watchdog input.

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

activated.