TDA8137 datasheet(4/5 Pages) STMICROELECTRONICS

4 / 5 page

RESET

IN1

DISABLE

TDA8137

C3 = 10

µF

TYPICAL APPLICATION

CIRCUIT DESCRIPTION

The TDA8137 is a dual voltage regulator with Reset

and Disable.

The two regulation parts are supplied from one

voltage reference circuit trimmed by zener zap

during EWS test. Since the supply voltage of this

last is connected at Pin 1 (VIN1), the regulator 2 will

not work if the Pin 1 is not supplied.

The outputs stages have been realized in dar-

lington configuration with a drop typical of 1.2V.

The disable circuit, switches off the output 2 if a

voltage lower than 0.8V is applied at pin 3.

The Reset circuit checks the voltage at the output

1. If this one goes below VOUT - 0.25V (4.85V Typ.),

the comparator "a" (see Figure 1) discharges rap-

idly the capacitor Ce and the reset output goes at

once low. When the voltage at the OUT 1 rises

above VOUT -0.2V (4.9V Typ.), the voltage VCe

increases linearly to 2.5V corresponding to a delay

td following the low : td

⋅ 2.5V

µA

(see figure 2),

then the reset output goes high again. To avoid

glitches in the reset output, the second comparator

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

TDA8137

4/5

TDA8137 Datasheet(PDF) 4 Page - STMicroelectronics