VNQ810M datasheet(10/21 Pages) STMICROELECTRONICS

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VNQ810M

Solution 2: A diode (DGND) in the ground line.

A resistor (RGND=1kΩ) should be inserted in parallel to

DGND if the device will be driving an inductive load.

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 (

j600mV) 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.

Series resistor in INPUT and STATUS lines are also

required to prevent that, during battery voltage transient,

the current exceeds the Absolute Maximum Rating.

Safest configuration for unused INPUT and STATUS pin

is to leave them unconnected.

LOAD DUMP PROTECTION

Dld is necessary (Voltage Transient Suppressor) if the

load dump peak voltage exceeds VCC max DC rating. The

same applies if the device will be subject to transients on

the VCC line that 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

transients are present on the VCC line, the control pins will

be pulled negative. ST suggests to insert a resistor (Rprot)

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

µC I/Os.

-VCCpeak/Ilatchup ≤ Rprot ≤ (VOHµC-VIH-VGND) / IIHmax

Calculation example:

For VCCpeak= - 100V and Ilatchup ≥ 20mA; VOHµC ≥ 4.5V

Ω ≤ R

prot ≤ 65kΩ.

Recommended Rprot value is 10kΩ.

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