TPS63050: 1.35Mhz Switching frequency?

Will Jarrett

Part Number: TPS63050

Team,

I have a customer who is using the TPS63050RMWR and then are measuring a 1.35Mhz switching frequency. The device is is regulating well, but it is not switching at the expected 2.5 Mhz... They are seeing poor EMI performance at 1.35 Mhz. The PFM pin is pulled high and is measuring 5V. The load current is about 300mA. When the load is increased to 400mA the frequency decreases to 900khz. Schematic follows webench and datasheet recommendations and nothing stood out to me. Any ideas on how this device could be switching at anything other than 2.5 Mhz?

Thank you!

over 3 years ago

0 Minqiu Xie over 3 years ago

TI__Mastermind 21565 points

Hi Will:

Would they confirm the power save mode is disable?

I would like to check the waveform of L1, L2, and Vout with varied load condition.

0 Will Jarrett over 3 years ago in reply to Minqiu Xie

TI__Intellectual 2885 points

Hi Minqiu,

The PFM/PWM pin is pulled high which should disable power save mode. I'll see if I can get the waveforms you requested. Thank you.

0 Minqiu Xie over 3 years ago in reply to Will Jarrett

TI__Mastermind 21565 points

Hi Will:

Yes, I see it with your description, but I still prefer to confirm it with customer if it's reliable. As the phenomenon is similar to power save mode.

Let's waiting for the waveform, it would be clearer.

0 Minqiu Xie over 3 years ago in reply to Minqiu Xie

TI__Mastermind 21565 points

Hi Will:

As we have another contact way, please allow me close this post. Thanks for kind understanding.

0 Will Jarrett over 3 years ago in reply to Minqiu Xie

TI__Intellectual 2885 points

Yes, thank you. It was helpful to understand that this is normal behavior, when Vin is close to Vout. When the converter will work between Boost and Buck phase. Thank you!

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TPS63050: 1.35Mhz Switching frequency?