LMZ31707: PWRGD seems sensitive

Yonghui zhu

Part Number: LMZ31707

Hi Expert,

I am using LMZ31707RVQ. PWRGD seems sensitive if a sudden load turn-on on its output after it's startup. Can I use a RC network to sense+ pin to decrease the sensitivity like other DC/DC converter? such as 100ohm series to output and 0.1uF to GND. Not sure sens+ is high impedance input.

Thanks

Peter

over 2 years ago

0 Yonghui zhu over 2 years ago

Intellectual 430 points

0 Yitzhak Bolurian over 2 years ago in reply to Yonghui zhu

TI__Mastermind 18370 points

Hi Yonghui zhu,

We would not recommend an RC low pass filter on Sense signal.
As this may adversely effect the compensation/regulation.

To reduce the sensitivity, you should guard this signal by either.

1) If PCB is used, have your "Sense signal PCB trace" to be surrounded with two traces at both sides in parallel.
When these two parallel traces at both sides are connected to Vout or GND and guard the signal from noise that might be injected to this Sense signal. And of course make sure to keep the Sense trace away from the inductor and keep it as short as possible.

2) If cable/wire is used, use a shielded cable, when the shield is connected to Vout or GND.

Hope this helps.

Regards,

Yitzhak Bolurian

0 Yonghui zhu over 2 years ago in reply to Yitzhak Bolurian

Intellectual 430 points

Thanks Yitzhak, we will consider load soft start also.

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LMZ31707: PWRGD seems sensitive