VND830MSP datasheet(9/18 Pages) STMICROELECTRONICS

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VND830MSP

µC I/Os PROTECTION:

If a ground protection network is used and negative

transient 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.

OPEN LOAD DETECTION IN OFF STATE

Off state open load detection requires an external pull-up

resistor (RPU) connected between OUTPUT pin and a

positive supply voltage (VPU) like the +5V 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 VOUT to be higher than

VOlmin; this results in the following condition

VOUT=(VPU/(RL+RPU))RL<VOlmin.

2) no misdetection when load is disconnected: in this

case the VOUT has to be higher than VOLmax; this

results in the following condition RPU<(VPU–VOLmax)/

IL(off2).

Because Is(OFF) may significantly increase if Vout is pulled

high (up to several mA), the pull-up resistor RPU should

be connected to a supply that is switched OFF when the

module is in standby.

The values of VOLmin, VOLmax and IL(off2) are available in

the Electrical Characteristics section.

VOL

V batt.

VPU

RPU

DRIVER

LOGIC

INPUT

STATUS

VCC

OUT

GROUND

IL(off2)

Open Load detection in off state

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