TPS3808: what is minimum current on sense pin

dimitry chen

Expert 1145 points

Part Number: TPS3808

Tool/software:

My current setting is

3v3 x 4.7M/22M+4.7M = 0.55V

and current is 3.3 V / 24.7M ohm = 133 nA

is this design OK?

6 months ago

0 Sila Atalar 6 months ago

TI__Genius 9960 points

Hi Dimitry,

The adjustable variant has (TPS3808G01) has 0.405V threshold, and the reset will be low when 3.3V rail goes below than 2.3V due to the resistor divider configuration you have at SENSE pin.

It seems like you need to have a bigger pull-up resistor value. The absolute maximum current for RESET pin is 5 mA. Currently it's 5.9 mA.

Best Regards,

Sila

0 dimitry chen 6 months ago in reply to Sila Atalar

Expert 1145 points

Hi Sila

In my view piont.

VDD is + 3.3A , but sense is 3.3V ，they are use dffrenet voltage.

My concern is TPS3808 can't detec sense pin due to too low sense current.

Can you help me to check if current design on sense pin is ok or not ?

+1 Sila Atalar 6 months ago in reply to dimitry chen

TI__Genius 9960 points

Hi Dimitry, It should work but your accuracy will be affecting.

Please find the graph for shows the relation between Accuracy and Current Variations through the Divider in below for TPS3808G01. We have an App note on this.

App note link: https://www.ti.com/lit/an/slva450b/slva450b.pdf?ts=1743097547135&ref_url=https%253A%252F%252Fwww.google.com%252F

I think using TPS3808E might be better in this case. This is next gen and it's is a low Iq device.

Best,

Sila

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TPS3808: what is minimum current on sense pin