UCD9090A: Device behavior if TRST is OPEN

Oba

Genius 17295 points

Part Number: UCD9090A

Hello,

What could happen if TRST pin is open in UCD9090A?
I need this information for functional safety standpoint.

Regards,
Oba

over 6 years ago

0 yihe over 6 years ago

TI__Guru 65610 points

Hello Oba
This pin must be pull down with 10Kohm resistor. the device may not function normal if the pin is floating.
Regards
Yihe

0 Oba over 6 years ago in reply to yihe

TI__Genius 17295 points

Hello Yihe,

Usually TRST is reset signal for something special function like debug mode or test mode in MCU.
Is that same in UCD9090A?
So the behavior when TRST is unpredictable. Correct?
Is there even a possibility that firmware or user configuration in internal flash memory is removed?

Regards,
Oba

0 yihe over 6 years ago in reply to Oba

TI__Guru 65610 points

Hi Oba
yes, it is a test reset signal. It must be pull down to get expected functions otherwise the results is unexpected.
Is there a problem to have this pin pull-down?
Regards
Yihe

0 Oba over 6 years ago in reply to yihe

TI__Genius 17295 points

Hello,

No, there is no problem to have a pull-down.
This is just a part of failure mode analysis.

Thank you.
Regards,

Power management

Power management forum

UCD9090A: Device behavior if TRST is OPEN