TPS62160-Q1: TPS62160-Q1 inquiry

Jon

Part Number: TPS62160-Q1

Tool/software:

Hello!
I'm using TPS62160-Q1 in one of my boards to generate a 5V output from 12V input. I've built the circuit to look like this one in the datasheet, changing the values of inductor and FB resistors to match the application requirements. while testing I've noticed a weird thing the voltage at the pin after the pull up resistor ( marked in red ) was 3.5V and not 5V ! I'm using 100k as a pull up resistor.
could you help explaining why such a thing could happen ?
Thanks in advance

over 1 year ago

0 Colin Chen over 1 year ago

TI__Mastermind 21361 points

Hi Jon,

Is the output 5V as you set in this condition？

I see the schematic is fine, PG should be 5V if output is normal.

Thanks,

Colin

0 Jon over 1 year ago in reply to Colin Chen

Prodigy 40 points

Hi Colin,
Thank you for your reply. The output is 4.89V and the voltage at PG pin (the red marked in the previous picture) is 3.56V
Would appreciate your help!

0 Colin Chen over 1 year ago in reply to Jon

TI__Mastermind 21361 points

Hi Jon,

Could you test the impedance of PG to GND?

I am afraid there maybe some leakage current from PG to GND.

Thanks,

Colin

0 Jon over 1 year ago in reply to Colin Chen

Prodigy 40 points

Hi Colin,
I've measured the impedance between PG and GND and it's 190kohms
Thanks,
Jon

0 Colin Chen over 1 year ago in reply to Jon

TI__Mastermind 21361 points

Hi Jon,

That can meet our suspicion.

Usually it should be high impedance with PG to GND, because the internal PG is a open drain mos to GND.

I think there may be some unexpected things in your layout.

Can you remove the IC and test the PG test point to GND again. If so, we can confirm that the must be layout or pcb problem.

Thanks,

Colin

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TPS62160-Q1: TPS62160-Q1 inquiry