TPS568215: Question for upper/lower resistors for Vout setting

HSU HANWEN

Part Number: TPS568215
Other Parts Discussed in Thread: UCD90320

I want to check if following hardware setting will have risk or not?

1. Nomial Vout = 5V.

Rupper = 11.3k ohm

Rlower = 1.54k ohm

2. Nomial Vout = 3V3.

Rupper = 2.21k ohm

Rlower = 10k ohm

3. Nomial Vout = 1V8.

Rupper = 10k ohm

Rlower = 4.99k ohm

+1 Athos Zhao over 2 years ago

Hi Hanwen,

HSU HANWEN said:
1. Nomial Vout = 5V.

Rupper = 11.3k ohm

Rlower = 1.54k ohm

It's ok.

HSU HANWEN said:
2. Nomial Vout = 3V3.

Rupper = 2.21k ohm

Rlower = 10k ohm

I guess you get the resistors reversed.

It's ok that Rupper = 10k ohm and Rlower = 2.21k ohm.

HSU HANWEN said:
3. Nomial Vout = 1V8.

Rupper = 10k ohm

Rlower = 4.99k ohm

It's ok.

You can also refer to datasheet Table 5. Recommended Component Values to select the resistors.

0 HSU HANWEN over 2 years ago in reply to Athos Zhao

Hi Athos:

Since I use UCD90320 to do Margin function and Rupper will affect vout overshoot, so I need to decrease value of Rupper.

Thanks for your help.

+1 Athos Zhao over 2 years ago in reply to HSU HANWEN

Hi HANWEN,

It's ok. No thanks.

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