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VN750 / VN750S / VN750-B5

1

GND

PROTECTION

NETWORK

AGAINST

REVERSE BATTERY

can be used with any type of load.

The following is an indication on how to dimension the

be found in the absolute maximum rating section of the

device’s datasheet.

battery situations) is:

GND

This resistor can be shared amongst several different

HSD. Please note that the value of this resistor should be

sum of the maximum on-state currents of the different

devices.

Please note that if the microprocessor ground is not

and the status output values. This shift will vary

depending on many devices are ON in the case of several

If the calculated power dissipation leads to a large resistor

or several devices have to share the same resistor then

the ST suggests to utilize Solution 2 (see below).

This small signal diode can be safely shared amongst

several different HSD. Also in this case, the presence of

the ground network will produce a shift (j 600mV) in the

input threshold and the status output values if the

microprocessor ground is not common with the device

ground. This shift will not vary if more than one HSD

shares the same diode/resistor network.

LOAD DUMP PROTECTION

are greater than the ones shown in the ISO T/R 7637/1

table.

µC I/Os PROTECTION:

If a ground protection network is used and negative

in line to prevent the

µC I/Os pins to latch-up.

The value of these resistors is a compromise between the

leakage current of

µC and the current required by the

HSD I/Os (Input levels compatibility) with the latch-up limit

of

µC I/Os.

Calculation example:

5k

Ω ≤ R

1

APPLICATION SCHEMATIC

GND

OUTPUT

µC

+5V

STATUS

INPUT

+5V