TPS1H000-Q1: GND network: Which ground connection of input pins?

Oliver Filsch

Intellectual 430 points

Part Number: TPS1H000-Q1

Tool/software:

Hello,

I intend to use a GND network according datasheet to implement reverse-current protection (see Fig. 30)

I use the following values: Resistor 1k, Diode Nexperia BAT46WJ

Datasheet requires diode Vf<0.6V. Vf of BAT46WJ: max. 0.35V @ 10mA / max. 0.475V @ 50mA.

To my question: regarding connection of CL pin, there is following note: Note that if using a GND network which causes a level shift between the device GND and board GND, the CL pin must be connected to the device GND.

What about the other pins that require a GND connection?

For example pin IN: in my design is an external pull-down resistor that acts as working resistance of an optocoupler output. To which GND should it be connected?

other pins: DIAG_EN, DELAY.

Regards, Oliver.

5 months ago

0 Alan Whitehead 5 months ago

TI__Genius 10285 points

Hey Oliver,

The I/O pins should be on the same GND as the microcontroller or whatever is being used to control them.

BR,

Alan

0 Oliver Filsch 5 months ago in reply to Alan Whitehead

Intellectual 430 points

Hi Alan,

thanks for the suggestion.

Regarding Pin IN: I would connect the external pull-down to board GND. When the optocoupler that connects to this pull-down is off, the voltage seen by the IC at IN pin would be approx. -0.3V (because of schottky diode voltage in GND network). This is within max. abs. ratings of the IC.

Regarding Pin DELAY: I think this pin should be connected to device GND, not board GND, because the introduced voltage shift (GND network) could falsify the configured delay time in latch-off mode:

Do you agree?

0 Alan Whitehead 5 months ago in reply to Oliver Filsch

TI__Genius 10285 points

Hello,

Yes, IN to board GND and DELAY to IC_GND. The IN pins have internal pull-downs to cut down on cost external pull downs may not be necessary.

BR,

Alan

0 Oliver Filsch 5 months ago in reply to Alan Whitehead

Intellectual 430 points

Thanks a lot!

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TPS1H000-Q1: GND network: Which ground connection of input pins?