TPS60403: TPS60403DBVR

Minglai Kao

Intellectual 635 points

Part Number: TPS60403
Other Parts Discussed in Thread: TPS60400EVM-178

I cannot get a negative voltage at the output with 2.0V input. I got ~+0.3V instead.

I use 3 1uF cap at input, output and for Cfly.

The board is TI TPS60400EVM-178.

over 6 years ago

0 Clemens Ladisch over 6 years ago

Guru 317250 points

Please show a picture of the board.
What capacitor model are you using?

0 Minglai Kao over 6 years ago in reply to Clemens Ladisch

Intellectual 635 points

Hi Clemens,

Thanks for looking into this.

The caps : C0603X5R0J105M030BC

0 Chris Glaser over 6 years ago in reply to Minglai Kao

TI__Guru**** 150900 points

Hi Minglai,

Can you repost your image? Can you also add a waveform of Vin and Vout?

0 Minglai Kao over 6 years ago in reply to Chris Glaser

Intellectual 635 points

I use this for DC. There is no waveform.

0 Minglai Kao over 6 years ago in reply to Chris Glaser

Intellectual 635 points

input bottom trace, output top trace, 10x probes.

0 Minglai Kao over 6 years ago in reply to Chris Glaser

Intellectual 635 points

The waveforms taken with no load.

0 Chris Glaser over 6 years ago in reply to Minglai Kao

TI__Guru**** 150900 points

Hi Minglai,

Your images aren't appearing. Here's an FAQ for how to insert an image: e2e.ti.com/.../761613

0 Minglai Kao over 6 years ago in reply to Clemens Ladisch

Intellectual 635 points

0 Clemens Ladisch over 6 years ago in reply to Minglai Kao

Guru 317250 points

You have populated the step-down part of the EVM (see section 2.4 of the EVM manual). The output voltage will be positive, and half the input voltage (lower if the output is loaded). What are C34 and R30?

To get a negative voltage, use the standard inverter layout (see figure 2-2 in section 2.1 of the manual); the filter/regulator parts are optional.

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TPS60403: TPS60403DBVR