PS12

Features

Power supply sequencer with four outputs

Power-up and power-down sequencing

Six programmable delays

Maximum 90V supply voltage

Input voltage window comparator

Low power supply current (500µA typical)

16-Lead SOIC Package

Applications

Reduction of transient current demand and

protection of sensitive loads

Telecom and networking systems

High voltage MEMS and display driver supplies

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General Description

Many systems require that their power supplies are enabled

and disabled sequentially in order to reduce transient current

demand on the power bus, or to avoid damage to components

having multiple supply voltages such as microprocessors,

ASICs, MEMS drivers, etc.

The PS12 incorporates a power-up delay timer, a window

voltage comparator, 4 open drain enable outputs, and 6

enable delay timers. The enable delays are individually

programmable for both the power-up (ABCD) and the power-

down (DCBA) sequence.

Power-up and power-down are controlled by a window

comparator formed by the ON and OV voltage comparators.

V

outside of the window maintains or initiates power-down. The

power-up sequence may be interrupted while in progress. The

power-down sequence, once initiated, cannot be interrupted

until it is brought to completion.

Typical Application Circuit

Quad Power Sequencing Controller

ENA

11

+12V

8

R

DC

9

R

CB

10

R

BA

C

PUD

OUT

OUT

ENA

12

OUT

ENA

13

OUT

ENA

14

R

2

R

3

R

1

3

4

15

2

5

R

AB

6

R

BC

7

R

CD

1

+5V

CONVERTER

+3.3V

CONVERTER

+1.8V

CONVERTER

+12V

CONVERTER

PS12NG

TCB

TBA

PUD

PSD

PSC

PSB

PSA

TDC

OV

ON

TBC

TCD

TAB

VIN

VEE