TPS7A20: TPS7A2033

Hi Zhou,

Could you please share scope shots and a schematic? I can begin troubleshooting with some more information about your application.

Thank you,

Erin

this is my schematic.

Hi Zhou,

Thank you! It looks like you have this device configured as recommended in the datasheet.

I want to understand what you mean when you say the device doesn't work, could you share scope shots of input voltage, output voltage and current? Are you supplying 100mA to the LDO or is your power supply current limit set to 100mA?

BR,

Erin 

my Load is less 100mA, And LDO Input is 3.9VDC，Output is 3.3VDC。 but，when my LDO Power On ， My LDO input becomed 0.8v，And Output becomed 0.5V .so,  the device doesn't work.

but When I used a linear power supply/ wjth 3.3V/100mA  , Load is working OK。

I changed the LT1117-3.3. OK , Load is 13mA。

Hi Zhou,

Have you reached out to the buck team to ask about LMR54406? I suspect that if the LDO works when you use a linear  power supply but not with the buck then the issue may be with the buck and not the LDO. 

BR,

Erin