STV8162 datasheet(6/14 Pages) STMICROELECTRONICS

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Circuit description

STV8162

6/14

Circuit description

The STV8162 and STV8162D are triple-voltage regulators with reset and disable functions.

The three regulation parts are supplied from a single voltage reference circuit trimmed by

zener zapping during EWS testing. Since the supply voltage of this voltage reference is

connected to pin INPUT1 (VIN1), the second and third regulators will not work if pin INPUT1

is not supplied.

The output stages are designed using a Darlington configuration with a typical dropout

voltage of 1.0 V.

In all applications, all three inputs must be polarized. If outputs 2 or 3 are not used, the

corresponding inputs must be connected to Input 1.

The disable circuit will switch off pins OUTPUT2 and OUTPUT3 if a voltage less than 0.8 V

is applied to pin DISABLE.

The reset circuit checks the voltage at pin OUTPUT1. If this voltage drops below

VOUT1-0.25 V (4.75 V Typ.), the "a" comparator (Figure 4) rapidly discharges the external

capacitor (Ce) and the reset output immediately switches to low. When the voltage at pin

OUTPUT1 exceeds VOUT1-0.175 V (4.825 V Typ.), the VCe voltage increases linearly to the

reference voltage (VREF = 2.5 V) corresponding to a reset pulse delay (tRD)as shown in

Figure 5.

Afterwards, the reset output returns to high. To avoid glitches in the reset output, the second

comparator "b" has a large hysteresis (1.9 V).

2.5V

μA

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STV8162 Scheda tecnica(PDF) 6 Page - STMicroelectronics