TPSM82821: 6uA current flows feedback divider

Kazuto Tatsumi

Part Number: TPSM82821

Hi team,

According to the datasheet, at least 6uA current is required in the voltage divider. Does it mean the current flow from VOUT to GND, correct? because the leakage current at FB is 0.01uA.

Additionally, is it no problem to place the resistor in parallel (1M and 820k) to get 450kOhm at R1?

Regards,
Kazuto

over 2 years ago

+1 Varun John over 2 years ago

TI__Genius 13240 points

Hi Kazuto,

6uA would be the current flowing from VOUT to GND via R1 & R2. Yeah using the 2 parallel resistors for R1 should also work.

Best regards,

Varun

0 Kazuto Tatsumi over 2 years ago in reply to Varun John

TI__Intellectual 2820 points

Hi Varun,

Thanks for your quick reply!

Regards,
Kazuto

0 Kazuto Tatsumi over 2 years ago in reply to Kazuto Tatsumi

TI__Intellectual 2820 points

Hi Varun,

The customer wants to get 3.3V so that R1=450kohm and R2=100kohm. Then the current is barely 6uA, is it enough to get the voltage accuracy on the datasheet?

Regards,
Kazuto

+1 Varun John over 2 years ago in reply to Kazuto Tatsumi

TI__Genius 13240 points

Hi Kazuto,

3.3V with R1=450KOhm and R2=100KOhm should result in 6uA through the FB divider. The datasheet schematic for 1.8V has R1=200KOhm and R2=100KOhm, which also results in 6uA. So this should be ok.

If you want to have some margin you can reduce the values of both the resistors.

Best regards,

Varun

0 Kazuto Tatsumi over 2 years ago in reply to Varun John

TI__Intellectual 2820 points

Okay thanks!

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TPSM82821: 6uA current flows feedback divider