TPS763: TPS763 En Input Current

Michael Huang3

Part Number: TPS763

Hi TEAM,

We read the datasheet of TPS763-Q1, but the input current of EN pin is -0.5uA maximum in Page 5. What I don't understand is

1) Why is the current negative

2) Why is the current is negative no matter the EN is connected with VIN and 0.

Could you share how to measure this specs in your side, and how you define this spec?

Thanks,

Michael

over 7 years ago

0 Ryan Eslinger over 7 years ago

TI__Guru 55940 points

Hi Michael,

The negative current is depicting that the current is flowing into the device; however, it is really the magnitude that is important. In your application you need to make sure that your enable rail can drive at least Ien max.

The EN pin is a digital input to the LDO; therefore, very little current will flow through the EN pin. This is why the limits are the same regardless of if the LDO is enabled or disabled.

Very Respectfully,
Ryan

0 Michael Huang3 over 7 years ago in reply to Ryan Eslinger

TI__Intellectual 2460 points

Hi Ryan,

Thanks for your reply.
But when EN=0, how can there be input current into the pin? The negative value doesn't make sense.
When EN=IN, EN has voltage higher than GND. When EN=0, the input current should be 0 or positive...

Regards
Michael

0 Ryan Eslinger over 7 years ago in reply to Michael Huang3

TI__Guru 55940 points

Hi Michael,

It is difficult to measure small currents and voltages. Furthermore, in order to keep test costs down the amount of time that a voltage is allowed to settle before a measurement is taken is limited. Due to this, Ven may not be at exactly 0 V when the measurement is taken.

Very Respectfully,
Ryan

0 Michael Huang3 over 7 years ago in reply to Ryan Eslinger

TI__Intellectual 2460 points

Hi Ryan,

Understand that if you drive EN with some IO, the IO may not get 0 perfectly... But connect to GND will provide a perfect 0. It is not possible that the current go into the pin. Maybe the current will flow out through the EN pin.
Customer and I only concern about the positive and negative.

Regards
Michael

0 Ryan Eslinger over 7 years ago in reply to Michael Huang3

TI__Guru 55940 points

Hi Michael,

Our ICs are tested on an automated tester with EN being driven by an IO.

Very Respectfully,
Ryan

0 Michael Huang3 over 7 years ago in reply to Ryan Eslinger

TI__Intellectual 2460 points

Ryan,

I know what you mean. But it is impossible that the current will go into the pin when EN pin is connected to GND. It is nature theory.

Regards
Michael

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TPS763: TPS763 En Input Current