TPS1663: SHDN pin

Keyao Sun

Part Number: TPS1663

HI,

For the SHDN pin, in the datasheet, it is written "Pulling SHDN low makes the device to enter into low power shutdown mode. Cycling SHDN pin voltage resets the device that has latched off due to a fault condition".

I am not very clear about it. If I want to enable this chip, do I need to give a voltage like 4V to this pin? Or can I float this pin? I use this eFuse on the high voltage secondary side of my converter, so to find a 4V may become a problem, or can I just use a voltage divider to provide a 4V with no current capability?

For reset the latch off, what should I do? Is it correct to connect to the GND by a OFF-MOM switch?

Thank you for you patience and help.

Keyao

over 6 years ago

0 Lokesh Ghulyani over 6 years ago

TI__Expert 8630 points

Hello Keyao,

We are looking into this and get back in couple of days.

0 Lokesh Ghulyani over 6 years ago in reply to Lokesh Ghulyani

TI__Expert 8630 points

Hello Keyao,

To enable the device, the SHDN pin has to be pulled above 2V. SHDN pin has internal pull-up and it can be left floating to enable the device.

To bring the device into low current shutdown mode, the SHDN pin needs to be pulled below 0.8V, this can be done using an NPN transistor OR Signal NMOS FET or an opto-isolator .

It is recommended to limit the voltage at SHDN pin between 0 to 4V. This can be done by using an external resistor divider.

0 Keyao Sun over 6 years ago in reply to Lokesh Ghulyani

Prodigy 90 points

Hi Lokesh,

Thank you very much for your reply.

Regards,

Keyao

Power management

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TPS1663: SHDN pin