VN750SMP-E Datasheet, PDF (17/27 Pages) STMicroelectronics – High side driver

VN750SMP-E
Electrical specifications
2.5.2
Solution 2: diode (D_GND) in the ground line
A resistor (R_GND=1 kshould be inserted in parallel to 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 produces a shift (600mV) in the input threshold
and in the status output values if the microprocessor ground is not common to the device
ground. This shift not varies 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.
2.6
Load dump protection
D_ld is necessary (voltage transient suppressor) if the load dump peak voltage exceeds the
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 7637/1 table.
2.7
Microcontroller I/Os protection
If a ground protection network is used and negative transient are present on the V_CC line,
the control pins is pulled negative. ST suggests to insert a resistor (R_prot) 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.
-V_CCpeak/I_latchup  R_prot  (V_OHµC-V_IH-V_GND) / I_IHmax
Calculation example:
For V_CCpeak= - 100 V and I_latchup  20 mA; V_OHµC  4.5 V
5 k  R_prot  65 k.
Recommended values: R_prot =10 k.
2.8
Open-load detection in off-state
Off-state open-load detection requires an external pull-up resistor (R_PU) connected between
output pin and a positive supply voltage (V_PU) like the +5 V line used to supply the
microprocessor.
The external resistor has to be selected according to the following requirements:
1. no false open-load indication when load is connected: in this case we have to avoid
V_OUT to be higher than V_Olmin; this results in the following condition
V_OUT=(V_PU/(R_L+R_PU))R_L<V_Olmin.
2. no misdetection when load is disconnected: in this case the V_OUT has to be higher than
V_OLmax; this results in the following condition R_PU<(V_PU–V_OLmax)/I_L(off2).
Doc ID 16812 Rev 2
17/27