TPD4S009: Ioff feature enquiry for TPS4S009

Leo Chow

Part Number: TPD4S009

Hi.

i have a few questions with regards to the Ioff feature which was mentioned in the datasheet under the "Description" section.

How VCC can enable the Ioff feature for the TPS4S009, can you elaborate more especially Ioff feature?

“The VCC pin allows all the internal circuit nodes to be at known potential during start-up time”. What is the benefit to users because we cannot access/ measure internal nodes at all?

If there is voltage transient for VCC, will the IC helps to clamp it if VCC pin is connected?

Thanks.

Regards,

Leo

over 7 years ago

0 Cameron Phillips over 7 years ago

TI__Genius 12410 points

Hello,
The "Ioff" feature is just saying to leakage of the I/O pins when there is no VCC present.
The benefit is that thew diode will breakdown after the VCC because it is biased to that level. Also it lowers the capacitance of the I/O pins
Yes the Device will clamp if there is a VCC provided it will just not clamp until after that VCC (if VCC is in a safe operating range).
Regards,
Cameron

0 Leo Chow over 7 years ago in reply to Cameron Phillips

TI__Expert 3120 points

Hi Cameron,

When VCC pin supplied with +5V the diode clamp starts if voltage transient > 5V. What if the VCC pin is connected to ground, when/will the diode clamp starts to work?

0 Cameron Phillips over 7 years ago in reply to Leo Chow

TI__Genius 12410 points

Hello,
The device will start clamping at the breakdown voltage, 9V.

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TPD4S009: Ioff feature enquiry for TPS4S009