3

U6803B

4762A–AUTO–11/03

Basic Circuitry

comply with its electrical characteristics. An external buffer capacitor of C = 100 nF is

supply pin.

All input stages are provided with an integrated 250 k

W pull-up resistor and can be

directly connected to a microcontroller.

All output stages are open collectors, each capable of sinking 20 mA. Recommended

external components:

•

Pull-up resistor, R = 1 k

W

•

Capacitor to GND, C = 470 pF, see Figure 3 on page 4

Functional Description

General

ON state: A low level at the input stage activates the corresponding output stage.

OFF state: The internal pull-up resistor provides a high level to the input comparator and

deactivates the output stage.

7 V Zener diodes between each input pin and GND are capable of ±10 mA clamping

currents without crosstalk on adjacent input stages.

A total clamping current of ±30 mA should be observed with respect to the power

dissipation.

Current Limitation of the

Output Stages and

Overtemperature

Shutdown

A temperature-dependent current limitation in the range of 25 to 100 mA protects the

stages in case of a short. Additionally, the chip temperature is monitored. For

Transients and Load

Dump

An integrated 28 V Zener diode protects each output stage against transients and load-

dump (Schaffner pulses). With the help of an external 1 k

W resistor, the output transistor

is capable of handling the corresponding current which flows during each of these condi-

tions. Apart from that, the outputs are short-circuit and overload protected.

Low-voltage Detection

When the supply voltage is switched on, a power-on reset pulse is generated internally

which disables all output stages until a defined supply-voltage level is reached. The

low-voltage detection is provided with a hysteresis of V