TPS25751: About internal LDO(LDO_3V3) output current

teritama

Part Number: TPS25751
Other Parts Discussed in Thread: MSPM0C1104

Tool/software:

Hi team,

Our customer want to boot this device setting from MCU, and they want to know LDO_3V3 output current capabirity to know if LDO_3V3 supply can be used as supply for low powerMCU or not without PP5V supply.

Please tell me the maximun output current of LDO_3V3.

Or when supply to MCU without PP5V supply, is it only way of supply for MCU is using other LDO device like TLV75533P like EVM configuration?

Please your opinion about above.

Best regards,

teritama

3 months ago

0 Chris Sterzik 3 months ago

TI__Guru 64881 points

Hello,

Please refer to the datasheet. https://www.ti.com/lit/ds/symlink/tps25751.pdf#page=11

If the TPS25751 is powered from VBUS and not VIN_3V3: The TPS25751 will maintain a minimum voltage of 3.0V on LDO_3V3 as long as the current is less than 18mA and VBUS is greater than 3.9V.

If the TPS25751 is powered from VIN_3V3, then you should take into consideration the Rdson from VIN_3V3 to LDO_3V3. However, if VIN_3V3 is available then I would consider powering the MCU directly from VIN_3V3.

I have done this experiment with the https://www.ti.com/tool/LP-MSPM0C1104 being powered from LDO_3V3 of the https://www.ti.com/tool/TPS25751EVM . I would recommend confirming with your specific MCU.

Regards,
Chris

0 teritama 3 months ago in reply to Chris Sterzik

Expert 2185 points

Hello Chris-san,

Thank you for your answer and experiment information with MSPM0C1104.

In your experiment with MSPM0C1104, did you use this MCU for boot TPS25751 setting?

and did you use no other power for PP5V and VIN_3V3?

Best regards,

teritama

+1 Chris Sterzik 3 months ago in reply to teritama

TI__Guru 64881 points

Hello,

teritama said:
In your experiment with MSPM0C1104, did you use this MCU for boot TPS25751 setting?

Yes.

teritama said:
and did you use no other power for PP5V and VIN_3V3?

I did two experiments. The first was with MCU 3V3 connected to the VIN_3V3 and both devices received power from an external source (non-deadBattery mode). The second was with the LDO_3V3 connected to the MCU 3V3 and the PD powered from the USBC connection (deadBattery mode). For this second experiment I did not use any power for PP5V or VIN_3V3.

Regards,

Chris

0 teritama 2 months ago in reply to Chris Sterzik

Expert 2185 points

Hello Chris-san,

Thank you for kindly explanation. It make sence and very helpful information.

Best regards,

teritama

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TPS25751: About internal LDO(LDO_3V3) output current