topic Re: Load Switch ILim Pin issue in Other NXP Products

Load Switch ILim Pin issue

kiran1 — Mon, 08 Oct 2018 04:09:58 GMT

Hi,

We are using the NX5P3290UKZ load switch in our design.
The input to the switch is 5V at 3A(max) and output is limited to 5V at 1A using resistor of 49.9Kohm on ILim pin of switch.
We are seeing an issue that when we power ON the board the ILim pin of switch get shorted with ground(0ohm with respect to ground).
Kindly let us know your thoughts on the same.

Thanks & Regards,

Kiran

Re: Load Switch ILim Pin issue

guoweisun — Tue, 09 Oct 2018 02:45:43 GMT

Hi,

Could you please show us your schematic?

Can you make sure that this is not your solder issue?

Re: Load Switch ILim Pin issue

kiran1 — Tue, 09 Oct 2018 04:30:43 GMT

Hi,

When we found that ILim pin got shorted with ground, we assumed load switch has gone bad and we replaced it with a new IC(Load switch). when we Powered it ON again we found a short on ILim pin.

Please find the Load switch schematics below.

Re: Load Switch ILim Pin issue

guoweisun — Wed, 10 Oct 2018 02:44:42 GMT

For your schematic please make sure:

1: C136 1nf/16V or 25V(at least).

2: Add external Schottky diode, NX5P3290 works well without it. To improve the lowest VBUS voltage during fast role swap, it is recommended to add a lower forward voltage diode, for example VF = 0.3 V.

3: Note the PCB layout, because of the CSP package with difficult solder. Suggest test the ILIM resistance with GND without power on.