PS10/PS11

6

A051204

Undervoltage/Overvoltage Operation

GND

Vin

PWRGD

SET RESET

Start-up Timing (PS11 PWRGD-A Active Low)

active. It can be approximated by

where

µA charge current

PWRGD Flags Delay Programming

When the ramp voltage hits Vint – 1.17V, PWRGD-A be-

comes active indicating that the input supply voltage is

within the programmed limits. PWRGD-B goes active after

a programmed time delay after PWRGD-A went active.

PWRGD-C goes active after a programmed time delay

after PWRGD-B went active. PWRGD-D goes active after

a programmed time delay after PWRGD-C went active.

determines the delay times between the PWRGD flags.

The value of the resistors determines the capacitor charg-

ing and discharging current of a triangular wave oscillator.

The oscillator output is fed into an 8-bit counter to gener-

ate the desired time delay.

The respective time delay is defined by the following equa-

tion:

and

Where

Vbg = 1.17V (internal band gap reference)

= 0.585 x 10

For a time delay of 200ms

= 0.585 x 10

For a time delay of 5ms

= 0.585 x 10