TPS3899: Drive digital transistor

Michiaki Tanii

Expert 4340 points

Part Number: TPS3899

Hello team,

Our customer is considering driving digital transistor with SVS such as TPS3899.

Is it ok to use SVS in order to drive digital transistor ?

Please let me know if there any concerns and your proposal.

Thank you and best regards

Michiaki

over 3 years ago

0 Ben C over 3 years ago

TI__Mastermind 27515 points

Hi Michiaki,

Can you provide more details on "driving digital transistor with SVS"? Are you suggesting is it ok to have the /RESET drive the gate of a MOSFET device?

Thank you,

Ben

0 Michiaki Tanii over 3 years ago in reply to Ben C

TI__Expert 4340 points

Hello Ben,

Yes, customer is considering use RESET IC to drive the base for a digital transistor not MOSFET.

Thank you and best regards,

Michiaki

0 Ben C over 3 years ago in reply to Michiaki Tanii

TI__Mastermind 27515 points

Hi Michiaki,

In essence, yes, you can drive the base of an NPN or PNP transistor but the speed to turn the digital transistor is affected by the value of the pull-up resistor and the sink capability of /RESET. I would suggest to use a schmitt trigger in between the SVS and the digital transistor.

Ben

0 Michiaki Tanii over 3 years ago in reply to Ben C

TI__Expert 4340 points

Hi Ben,

Customer would like to reduce the components, so how about the RESET that have push-pull output.

Thank you and best regards,

Michiaki

0 Ben C over 3 years ago in reply to Michiaki Tanii

TI__Mastermind 27515 points

Hi Michiaki,

A push-pull output would work but remember that:

1. The minimum voltage for the TPS3899 can operate is 0.7V, which may not be high enough for the bipolar device during certain conditions like at cold temperature.

2. The voltage output from /RESET is basically VDD or GND. Be aware that the Biploar devices turn on when VBE is 0.7V.

Ben

Power management

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TPS3899: Drive digital transistor