Datasheet

VNQ5E160K-E Application information
Doc ID 14471 Rev 4 23/34
If the calculated power dissipation leads to a large resistor or several devices have to share
the same resistor then ST suggests that Solution 2 is used (see below).
3.1.2 Solution 2: diode (D
GND
) in the ground line
A resistor (R
GND
=1kshould be inserted in parallel with D
GND
if the device drives an
inductive load.
This small signal diode can be safely shared amongst several different HSDs. Also in this
case, the presence of the ground network will produce a shift (
~600mV) in the input
threshold and in 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.
3.2 Load dump protection
D
ld
is necessary (Voltage Transient Suppressor) if the load dump peak voltage exceeds to
V
CC
max DC rating. The same applies if the device is subject to transients on the V
CC
line
that are greater than the ones shown in the ISO T/R 7637/2 table.
3.3 MCUI/Os protection
If a ground protection network is used and negative transients are present on the V
CC
line,
the control pins will be pulled negative. ST suggests the insertion of resistors (R
prot
) in the
lines to prevent the µC I/Os pins from latching up.
The values of these resistors are 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 the µC
I/Os.
-V
CCpeak
/I
latchup
 R
prot
 (V
OHC
-V
IH
-V
GND
) / I
IHmax
Calculation example:
For V
CCpeak
= - 100V and I
latchup
 20mA; V
OHC
 4.5V
5k  R
prot
 180k.
Recommended R
prot
value is 10k