TMUX7462F: Floating DR and FF pin

Art Mecina

Part Number: TMUX7462F

Hello Guys,

Good day.

Our customer is looking at the TMUX7462F as an alternative to a part they are using in a current design.
They are trying to understand how the device would perform if both the DR and FF pins were left completely unconnected.

From what they were seeing, DR being unconnected should just cause the transistor to fail open on a fault condition but they wanted to confirm that and the FF pin was unclear about how that would impact operation.

Thanks and regards,

Art

over 4 years ago

0 Rami Mooti1 over 4 years ago

TI__Mastermind 35648 points

Hey Art,

The DR pin behavior is described in the datasheet. "Drain Response (DR) input. Tying the DR pin to GND enables the drain to be pulled to VFP or VFN through a 40 kΩ resistor during an overvoltage fault event. The drain pin becomes open circuit when the DR pin is a logic high or left floating." The drain will be open circuit in the overvoltage fault events instead of being pulled to VFN or VFP.

The FF pin is just an open drain output. By leaving it floating it could make it confusing to identify when a fault event occurs so in terms of operation, they would lose that functionality. Either way, it will be pulled low internally when a fault event occurs.

Thanks,
Rami

0 Art Mecina over 4 years ago in reply to Rami Mooti1

TI__Genius 16795 points

Thanks Rami. To clarify, leaving the FF pin floating won't impact other functionality? Customer have no intention of using the FF pin so they don't care about it's functionality.

Thanks,

Art

0 Rami Mooti1 over 4 years ago in reply to Art Mecina

TI__Mastermind 35648 points

Hey Art, yes, they can leave it floating if they don't intend to use the functionality.

Thanks,
Rami

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TMUX7462F: Floating DR and FF pin