ATMEL U6803B User Manual

Triple Driver with Thermal Monitoring

Description

The triple-driver IC includes three non-inverted and
current-limited output stages with an open collector.
Common thermal shutdown protects the outputs against
critical junction temperatures. Each output can sink a

Features

 Three input comparators with Schmitt-trigger

characteristic

current of 20 mA, parallel output operation is possible.
The digital inputs have Schmitt-trigger function with
pull-up resistors to 5 V.

 ESD protection acording to human body model:

2000 V (C = 100 pF, R = 1.5 k)

U6803B

 Input clamping current capability of10 mA
 Integrated protection cells (EMC, ESD, RF)

dedicated to all input stages

 Common shutdown by junction-temperature monitor
 Reset with hysteresis at low voltage

Block Diagram / Applications

V

O1

1 3

7

V

S

Thermal

shutdown

Under-

voltage

detection

V

O2

856

V

I1

 Output stages:
– Short-circuit protected
– Load-dump protected @ 1 k
– No crosstalk on adjacent channels
– Jump start possible

V

O3

4

VS=5 V

V

I2

V

I3

V

S

13332

2

GND

Figure 1. Block diagram

Ordering Information

Extended Type Number Package Remarks

U6803B–FP SO8

Rev. A6, 28-Mar-01 1 (6)

U6803B

Pin Description

V

O1

GND

V

V

O2

O3

1

2

3

4

13330

Figure 2. Pinning

V

8

I1

V

7

S

V

6

I2

V

5

I3

Basic Circuitry

The integrated circuit U6803B requires a stabilized
supply voltage (VS = 5 V5%) to comply with its
electrical characteristics. An external buffer capacitor of
C = 100 nF value is recommended. An integrated 14-V
Zener diode between VS and ground protects the supply
pin.

All input stages are provided with an integrated 250-k
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:

Pin Symbol Function

1 V

O1

Output 1
2 GND Ground
3 V
4 V
5 V
6 V
7 V
8 V

O2
O3

I3
I2

I1

Output 2

Output 3

Input 3

Input 2

Supply voltage 5 V

S

Input 1

Current Limitation of the Output Stages
and Overtemperature Shut-down

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 T

chip

> 148C, all outputs are disabled and automatically
enabled with a hysteresis of T

Chip

> 5C.

Transients and Load Dump

Pull-up resistor, R = 1 k
Capacitor to GND, C = 470 pF, see figure 3

Functional Description

General

ON state: Low level at the input stage activates the
corresponding output stage.
OFF state: The internal pull-up resistor provides 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.

An integrated 28-V Zener diode protects each output
stage against transients and load-dump (Schaffner
pulses). With the help of external 1-k resistor, the output
transistor is capable to handle the corresponding current
which flows during each of these conditions. 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

= 0.5 V typically.

hyst

Rev. A6, 28-Mar-012 (6)