TPS65311-Q1: VRESL and pull up resistor

Kuramochi Tadahiko

Guru 28715 points

Part Number: TPS65311-Q1

Hi,

Though VRESL is specified as below, I would like to know this condition and how to design pull up resistor.

If a pull-up voltage is 3.3V, VRESL becomes below 0.4V by below 1.32kΩ(=3.3V/2.5mA) pull up resistor.

Is my understanding correct?

Best Regards,

Kuramochi

over 6 years ago

0 Nastasha over 6 years ago

TI__Genius 10000 points

Hi,

The responsible applications engineer has been assigned to this thread and will get back to you shortly.

Thanks,
Nastasha

0 Krishnamurthy Hegde over 6 years ago in reply to Nastasha

TI__Expert 8730 points

Hi Kuramochi -san,

Your understanding is correct. Typically they can use 4.7k ohm to 10 k ohm pull up to 3.3V.

Regards,

Murthy

0 Kuramochi Tadahiko over 6 years ago in reply to Krishnamurthy Hegde

Guru 28715 points

Murthy-san,

Thank you for your reply.

Does it mean that VRES below 0.4V is guaranteed by pull-up voltage 3.3V and resistor 4.7kΩ~10kΩ?

Best Regards,
Kuramochi

0 Krishnamurthy Hegde over 6 years ago in reply to Kuramochi Tadahiko

TI__Expert 8730 points

Hi Kuramochi -san,

Maximum RDSon drop across these low side transistors depends on the current flowing through it. In the datasheet, 2.5mA is the current we use to test this drop and we guarantee maximum of 0.4V. With higher resistor values I mentioned above, current flow is much less compared to 2.5mA and hence voltage drop across these low side transistors are also low. So, answer to your question is "Yes"

Regards,

Murthy

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TPS65311-Q1: VRESL and pull up resistor