TPS3899: spec check

GARETH OU

Part Number: TPS3899
Other Parts Discussed in Thread: TPS3422, TPS3808E,

Customers reported that the TPS3899DL30DSER board cannot be turned on after calling it back, and RST# has no effect. Can you help identify the problem? Thanks

3 months ago

0 Walter Zollinger 3 months ago

TI__Expert 7090 points

Hello,

I believe the issue is TPS3899DL30DSER has a fixed sense threshold of 3V but there is a resistor divider on the sense input. With a 3.3V input to the resistor divider, the sense pin is only seeing 0.57V and the device is detecting low. Please use the adjustable TPS3899DL01DSER. The TPS3899DL01DSER has a sense threshold of 0.505V and the resistor divider can be adjusted so that the device detects at the correct voltage.

Thanks,

Walter

0 GARETH OU 3 months ago in reply to Walter Zollinger

Mastermind 9675 points

Hi Walter

Does the sense have to be pulled low under 3V to reset Vout?

Is there no other way to make the ic reset in 2 seconds as soon as it is powered on?

Similar to MIC2788

Push-Button Reset IC (microchip.com)

0 Walter Zollinger 3 months ago in reply to GARETH OU

TI__Expert 7090 points

Hello,

For the TPS3899DL30DSER sense has to be pulled under 3V to trigger reset. For the TPS3899DL01DSER sense has to be pulled under 0.505V to trigger reset. You can use the reset delay delay and the TPS3899PH01 to get a similar waveform.

The TPS3422 has similar functionality to MIC2788 but with a longer 7.5s delay time.

Thanks,

Walter

0 GARETH OU 3 months ago in reply to Walter Zollinger

Mastermind 9675 points

Hi Walter

Do you mean to change it to TPS3899PH01? Is it possible to reset it by myself without having to pull the sense pin to Low?

0 Walter Zollinger 3 months ago in reply to GARETH OU

TI__Expert 7090 points

No this part does not have a manual reset function. TPS3899 is reset when sense is below the threshold. Our TPS3808E device has both a sense pin and manual reset.

Thanks,

Walter

Power management

Power management forum

TPS3899: spec check