TPS543C20: PGD pin sink current

Yuto Sakai

Part Number: TPS543C20

Hi,

I would like to know about the sink current when the PGD pin of the TPS543C20 is Low.
Although it is described as 15 μA when looking at the following, is it necessary to design with sink current within 15 μA?

Best Regards,
Yuto Sakai

over 7 years ago

0 JohnTucker over 7 years ago

TI__Guru**** 191445 points

Sakai-san,

That is the leakage current spec. The PGOOD pin is open drain. When the FET is off (PGOOD is "good") and the PGOOD pin is pulled up to 5 V, there can be leakage current up to 15 uA. That is the maximum. Typically the leakage is much less. Even the TI EVM uses 100 k for a pull up. I would be inclined to use a lower value though.

0 Yuto Sakai over 7 years ago in reply to JohnTucker

Mastermind 6100 points

Hi John-san,

Thank you for your reply.
When PGD = High, I understood that the leakage current is 15 μA at max.

In PGD = Low, I think that the sink current to the PGD pin depends on the pull-up voltage and the pull-up resistance.
Is there sink current limitation?
If yes, what ampere or less should the sink current be?

Best Regards,
Yuto Sakai

0 JohnTucker over 7 years ago in reply to Yuto Sakai

TI__Guru**** 191445 points

Sakai-san,

You are correct, it depends mostly on the pull up resistor as it will be large compared to the internal FET resistance (60 ohm max). For 5 V pull up voltage and 10 k pull up resistor, the current would be approximately 0.5 mA. That results in a pull down voltage of 0.3 V.

0 Yuto Sakai over 7 years ago in reply to JohnTucker

Mastermind 6100 points

Hi John-san,

Thank you for your reply.
When the PGD pin is low, could you tell me how much sink current to the PGD pin are allowed at max?
Since EVM pulls up 5V at 100 kΩ, I am worried about the problem with the current value flowing to the PGD pin.

Best Regards,
Yuto Sakai

0 JohnTucker over 7 years ago in reply to Yuto Sakai

TI__Guru**** 191445 points

Sakai-san,

I doubt that there is any specification for that, but I will check for it.

0 JohnTucker over 7 years ago in reply to JohnTucker

TI__Guru**** 191445 points

Sakai-san,

As I expected, there is no test data for sink current, only leakage current. If you can tell me your exact concern, I can offer you some guidance.

0 Yuto Sakai over 7 years ago in reply to JohnTucker

Mastermind 6100 points

John-san,

The customer connects a 10 kΩ resistor for 3.3 V pull-up. Since 100 kΩ is connected for 5 V pull-up in EVM, if there is a limit on sink current, I am worried that current will flow beyond that limit.
Is it OK to use a 10 kΩ pull-up resistor?

Best Regards,
Yuto Sakai

0 Yuto Sakai over 7 years ago in reply to Yuto Sakai

Mastermind 6100 points

Hi John-san,

Just checking to see if you received the E2E post and your thought on the matter.
I am still expecting your response regarding this post.

Best Regards,
Yuto Sakai

0 Yuto Sakai over 7 years ago in reply to Yuto Sakai

Mastermind 6100 points

Hi,

Is there an answer to this E2E post?
I do not have to guarantee, so please give me a view.

Best Regards,
Yuto Sakai

0 JohnTucker over 7 years ago in reply to Yuto Sakai

TI__Guru**** 191445 points

Sorry,

I did not see that you posted a reply. 10 k pulled up to 3.3 V results in 329 uA. That is not too much. It will result in approximately 9.9 mV pull down voltage.

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TPS543C20: PGD pin sink current