TPS63900: Noise in sleep mode

ulfat hussain

Part Number: TPS63900

Tool/software:

I am currently using the TPS63900 in my design (VIN: 3V and VOUT: 3.3V), which includes the primary ICs: the RAK3172 LoRaWAN module from RAKwireless and the BG95M2 LPWA Cat M1/Cat NB2 modem from Quectel. For power monitoring, I am using the Nordic Semiconductor Power Profiler Kit II to measure current consumption.

When the system enters sleep mode, the profiler kit registers an average current consumption of 990.69 µA, which is within the expected range. However, I have noticed intermittent noise peaks reaching up to 11 mA between intervals, which is concerning.

When I bypass the TPS63900 (by removing R40 as shown in the attached schematic) and supply 3.3V directly to the system, the waveform stabilizes, and no noise peaks are observed.

I am uncertain why the TPS63900 is introducing these noise peaks in sleep mode. Could you provide insights into the potential causes of this behavior?

Please find my schematics and the 4-layer PCB design attached for your reference.

11 months ago

0 Brigitte 11 months ago

TI__Guru 65340 points

Hello ulfat,

When the device operates in power save mode, it still regulates the output voltage. I expect these spikes are caused by the switching operation. You should be able to extend the intervals by increasing the output capacitor and the impact to the rest of the system by increasing the input capacitance by using different value capacitors on the input.

Best regards,
Brigitte

0 ulfat hussain 11 months ago in reply to Brigitte

Prodigy 90 points

Thanks for your reply. Can you suggest me how much I increase the input/output capacitors values to deal with this issue?

0 Brigitte 11 months ago in reply to ulfat hussain

TI__Guru 65340 points

Hello ulfat,

This is very dependent on the needs of your supply and load, so there is not a simple answer. I recommend checking with double the capacitance as you then can see in which direction it goes.

Best regards,
Brigitte

0 ulfat hussain 11 months ago in reply to Brigitte

Prodigy 90 points

Thanks

0 Yezi Yang 11 months ago in reply to ulfat hussain

TI__Prodigy 550 points

Hi Ulfat,

If you have more questions, our device expert can provide further assistance. If not, I will close this thread. Thank you.

Best regards

Yezi

Power management

Power management forum

TPS63900: Noise in sleep mode