TPS62140: Switching frequency is not as per datasheet

Vishal Batham7

Part Number: TPS62140
Other Parts Discussed in Thread: TPS84620, TPS82140, TPS62147

We are using TPS62140 for generating 1.1V and 1.5V , as per device datasheet, the switching frequency should 2.5MHz if pin FSW is floating. But observed frequency is not 2.5MHz.

Picture 1 and 2 shows the switching frequency of 1.1V and 1.5V , waveform observed at switch node pin of the device.

Please comment.

over 6 years ago

0 Chris Glaser over 6 years ago

TI__Guru*** 147230 points

Hi Vishal,

As explained in the D/S, the TPS62140 enters power save mode for light loads and here it reduces the switching frequency.

Since you are also using the TPS84620 module, you might like to use the TPS82140 module version of the TPS62140.

If you do prefer to stay with a discrete solution, I recommend the newer, smaller, more accurate TPS62147. This one offers a forced PWM mode to prevent the device from entering power save mode.

0 Vishal Batham7 over 6 years ago in reply to Chris Glaser

Prodigy 200 points

Hi Chris,

If i provide full load to converter then will i get the mentioned frequency?

Vishal
Fibcom India Ltd

0 Chris Glaser over 6 years ago in reply to Vishal Batham7

TI__Guru*** 147230 points

Running at full load instead of a light load will obtain a higher frequency, since you are out of power save mode. The frequency may still be below 2.5 Mhz, as explained here: www.ti.com/.../slyt646.pdf

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TPS62140: Switching frequency is not as per datasheet