U6805B ATMEL Corporation, U6805B Datasheet - Page 3

• Manufacturer Part Number: U6805B
• Description: U6805b Hex Driver Ic With Thermal Monitoring
• Manufacturer: ATMEL Corporation

3. Basic Circuitry
4. Functional Description
4.1
4.2
4.3
4.4
4763B–AUTO–09/05
General
Current Limitation of the Output Stages and Overtemperature Shutdown
Transients and Load Dump
Low-voltage Detection
The integrated circuit U6805B requires a stabilized supply voltage (V
its electrical characteristics. An external buffer capacitor of C = 100 nF is recommended. An
integrated 14V Z diode between V
All input stages are provided with an integrated 250 k pull-up resistor and can be directly con-
nected to a microcontroller.
All output stages are open collectors, each capable of sinking 20 mA. Recommended external
components:
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 deacti-
vates the output stage.
7V Zener diodes between each input pin and GND are capable of ±10 mA clamping current
without crosstalk on adjacent input stages.
A total clamping current of ±30 mA should be observed with respect to the power dissipation.
A temperature-dependent current limitation in the range of 25 to 100 mA protects the stages in
case of a short-circuit. Additionally, the chip temperature is monitored. If T
puts are disabled and automatically enabled with a hysteresis of T
driver U6807B if the temperature shutdown feature is not required.
An integrated 28V Zener diode protects each output stage against transients and load dump
(Schaffner pulses). With the help of an external 1 k resistor, the output transistor is capable of
handling the corresponding current which flows during each of these conditions. Apart from that,
the outputs are short-circuit and overload protected.
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 detec-
tion is provided with a hysteresis of V
Pull-up resistor, R = 1 k
Capacitor to GND, C = 470 pF, see
S
and ground protects the supply pin.
hyst
Figure 4-1 on page 4
= 0.5V typically.
S
Chip
= 5V ±5%) to comply with
> 5K. Refer to the hex
chip
> 148°C, all out-
U6805B
3