TPS2663: The resistor value for UVLO and OVP

Michiaki Tanii

Expert 4610 points

Part Number: TPS2663

Hi Team,

Could you kindly advise why the resistor value for UVLO and OVP is selected large number ?

Are there any concern if customer select smaller number of resistor like several k ohm ?

Thank you and best regards,

Michiaki

over 5 years ago

0 Rakesh over 5 years ago

TI__Guru** 105361 points

Hi Michiaki,

There are two reasons for selecting high value of resistors.

1. To minimize the shunt current from the input as explained in Section 10.2.2.2 Undervoltage Lockout and Overvoltage Set Point of the datasheet

2. In case of input reverse polarity condition, these high value of resistors limit the current in the internal clamping diodes. Please refer https://e2e.ti.com/support/power-management/f/196/t/881806 for more information.

Best Regards, Rakesh

0 Michiaki Tanii over 5 years ago in reply to Rakesh

TI__Expert 4610 points

Hello

Customer would like to put small resistor as possible as they can , considering the affect by noise due to small input current.

With the above reason, customer ask us to provide the exact number of our recommendation input current and customer will follow our recommendation number of input current.

If 300k ohm between UVLO and IN_SYS is mandatory, please share the reason why the resistor is specified 300k ohm.

Thank you and best regards,

Michiaki

0 Rakesh over 5 years ago in reply to Michiaki Tanii

TI__Guru** 105361 points

Hi Michiaki,

The min 300k requirement come to support input reverse polarity condition. Say -60V, the our ESD structures will see 60V/300k = 200uA which is safe level to not cause damage. 300k can be reduced to 60k, to limit ESD current to 1mA level which is still in the safe region.

If customer wishes to use much lower resistor values, the input R-ladder can be connected to IN pin instead of IN_SYS pin.

Best Regards, Rakesh

0 Michiaki Tanii over 5 years ago in reply to Rakesh

TI__Expert 4610 points

Hi Rakesh,

Does customer have the variation for 1mA you answered ?

Thank you and best regards,

Michiaki

0 Rakesh over 5 years ago in reply to Michiaki Tanii

TI__Guru** 105361 points

Hi Michiaki,

Please suggest to keep <1mA considering supply variations and resistor tolerances.

Thanks, Rakesh

0 Michiaki Tanii over 5 years ago in reply to Rakesh

TI__Expert 4610 points

Hi Rakesh,

Could you kindly advise where we can see about less than 1mA in the datasheet ?

And 1mA is defined by the internal diode specification ?

Thank you and best regards,

Michiaki

0 Rakesh over 5 years ago in reply to Michiaki Tanii

TI__Guru** 105361 points

Hi Michiaki,

Please use https://www.ti.com/lit/an/slaa689a/slaa689a.pdf as reference. In general, it is applicable to all semiconductor devices.

Best Regards, Rakesh

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TPS2663: The resistor value for UVLO and OVP