TPS62130A: Power supply dips for less than 1 microsecond which causes GSM module & Micro-controller latch

Anshuman Agarwal

Part Number: TPS62130A
Other Parts Discussed in Thread: TPS82130

Dear Sir,

I am using TPS62130A for powering a LTE GSM module with input as 12V DC and output as 4V. I am also using LP2950-3 for powering my microcontroller with input 4V.

I was facing an issue of micro-controller latch-up frequently, I monitored my 4V supply and found that the supply dips for less than 2 microseconds when gsm module draws current for pushing data on web and other network work loads.

I am using three 22uF caps and 1 100uF cap after inductor , I have tried with bigger values also but I was not able to succeed. Schematic is attached.8420.schematic.pdf

Please suggest a solution.

over 7 years ago

0 Chris Glaser over 7 years ago

TI__Guru**** 151520 points

Hi Anshuman,

Can you post a waveform of the spike you saw and the PCB layout with the location where this was measured?

On your schematic, the TPS62130A needs a 10uF ceramic input cap.

0 Chris Glaser over 7 years ago in reply to Chris Glaser

TI__Guru**** 151520 points

Hi Anshuman,

Is this still an issue?

0 Anshuman Agarwal over 7 years ago in reply to Chris Glaser

Prodigy 140 points

Dear Chris,

The issue is still there, I did not have snapshot capability in my DSO, I have ordered one, will get it shortly.

I am attaching a picture of my layout and I am measuring the signal on C1 capacitor.

Thanks & Regards

Anshuman Agarwal

0 Chris Glaser over 7 years ago in reply to Anshuman Agarwal

TI__Guru**** 151520 points

Thanks for sharing your layout. I don't see any vias. Are these just not showing in the picture?

It doesn't follow any of the recommendations around the Cin, Cout, and VOS pin routing: www.ti.com/.../slyt614.pdf. As well, I don't see much copper under the device to connect to the thermal pad and spread the heat.

We also have the TPS82130 module, which offers a much simpler design.

0 Anshuman Agarwal over 7 years ago in reply to Chris Glaser

Prodigy 140 points

Dear Sir,

I am hereby attaching layout in pdf for my board, I tried to make enough provision for vias in my board. Also there is a 470uF electrolytic capacitor on input for surge protection along with TVS diode.

Thanks

Anshuman Agarwal3022.schematic.pdf Bottom Layer.pdf Silkscreen Top.pdf Top Layer.pdf

0 Chris Glaser over 7 years ago in reply to Anshuman Agarwal

TI__Guru**** 151520 points

Thanks for sending. The pdf files do show the vias.

It is not just the amount of vias, but their placement, that is important. You have just one via under the IC. Vias placed here are much more effective than outside of the thermal pad. The recommended land pattern at the very end of the D/S shows 5 vias.

0 Chris Glaser over 7 years ago in reply to Chris Glaser

TI__Guru**** 151520 points

Hi Anshuman,

Were you able to get a scope to see the spike?

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TPS62130A: Power supply dips for less than 1 microsecond which causes GSM module & Micro-controller latch