1998 May 07

4

Philips Semiconductors

Product specification

Multiple voltage regulator with battery

detection

TDA3606A

FUNCTIONAL DESCRIPTION

The TDA3606A is a voltage regulator intended to supply a

microprocessor (e.g. in car radio applications). Because of

low voltage operation of the application, a low-voltage drop

regulator is used in the TDA3606A.

This regulator will switch on when the supply voltage

exceeds 7.6 V for the first time and will switch off again

when the output voltage of the regulator drops below

2.4 V. When the regulator is switched on, the RES1 and

RES2 outputs (RES2 can only be HIGH when RES1 is

HIGH) will go HIGH after a fixed delay time (fixed by an

external delay capacitor) to generate a reset to the

microprocessor.

RES1 will go HIGH by an internal pull-up resistor of 4.7 k

Ω,

and is used to initialize the microprocessor. RES2 is used

to indicate that the regulator output voltage is within its

voltage range. This start-up feature is built-in to secure a

smooth start-up of the microprocessor at first connection,

without uncontrolled switching of the regulator during the

start-up sequence.

All output pins are fully protected. The regulator is

protected against load dump and short-circuit (foldback

current protection).

Interfacing with the microprocessor can be accomplished

by means of a battery Schmitt-trigger and output buffer

(simple full/semi on/off logic applications). The battery

output will go HIGH when the battery input voltage

exceeds the HIGH threshold level.

Fig.3 Timing diagrams.

handbook, full pagewidth

2.1 V

VP

regulator

reset 1

50 V

4.35 V

4.35 V

2.4 V

2 V

2 V

2 V

reset 2

on/off switch

battery input

battery output

reset delay

capacitor

MGB857