Dear NXP Support Team,
We are currently working with the PF5020 Power Management IC and have configured the device in TBB mode (Try Before Buy) to verify and fine-tune our custom power-up configuration.
We are facing an issue where the LDO1 RUN voltage register is successfully written and read back through I²C, but the LDO1OUT pin voltage does not update to the programmed value. The change is visible in the register but not reflected on the output pin.
thank you,
Shivani e.
Dear Shivani,
I have discussed the PWRON connection to GND in the UM11377 for entering TBB mode, with application engineer. Application engineer confirmed, that this is a mistake. Please leave the PWRON floating, be removing the J34 jumper, for full MCU control. Please see below.
DESCRIPTION
If the PWRON connects to GND, all the regulators will no output. From the TBB script, the last sentence of the TBB script is :
SET_DPIN:PF5020:TBBEN:low
SET_DPIN:PF5020:PWRON:high
Another, do you check other regulators? whether they can be changed? do you have customer's TBB script?
This sentence should be no meaning, because the J34 should be open for full MCU control with no pull up.
With Best Regards,
Jozef
Dear Jozef,
According to the UM11377 document, in TBB mode, the PWRON pin is shown connected to GND.
However, in your earlier response, it was mentioned that the PMIC will not enable any regulators if PWRON = GND, and that it should be pulled high or controlled via the MCU.
Could you please clarify how the PWRON pin can be controlled via MCU in TBB mode,
Also, please confirm the correct connection and control sequence if the MCU is to handle PWRON.
Thank you for your support and clarification.
Best regards,
Shivani e.
Dear Shivani,
thank you for more information. I see an issue in the PWRON pin connection. The PMIC will not enable any regulator outputs if the global POWERON pin is low. In your wiring: PWRON = GND → This forces the PMIC into standby mode, regardless of I²C writes.
Fix:
Pull PWRON high (to VIN or VDDIO) or control it via MCU. Recommended is to control PWRON pin with your MCU.
Each regulator also needs its EN pin high. If EN pins are tied to GND, the regulator stays off even if RUN bit is set. Please make sure that EN4 is pulled high.
For the hardware, yes we have KITPF502xSKTEVM programming board. Recommended MCU board for communication with the KITPF502XSKTEVM is FRDM-KL25Z, included in the kit. Please refer to the UM11377 attached.
With Best Regards,
Jozef
Hi Jozef,
Thanks for your support. Below are the details from our side and our observations.
1) Registers we modified (values written)
0xC6 = 0x00
→ Configured LDO as programmable regulator (not load switch).0x71 = 0x06
→ Voltage setting for 2.8 V.0x6F = 0x02
→ Run bit set to enable output.
2) Scope of issue
All regulators are not reflecting the configured output voltages on their output pins.
We are able to write and read back the registers correctly via I²C, but the voltage changes are not taking effect on any of the regulator outputs.
3) Board / mode wiring
3) Board / mode wiring
TBBEN pin is pulled up to V1P5D.
VDDOTP = GND (TBB mode).
POWERON pin is connected to GND.
4) Furthermore, we would like to know whether there is any programming kit or GUI-based tool available for configuring and programming the PF5020 PMIC(MPF5020CMMACES). If such a tool exists, kindly provide details on its availability, recommended hardware interface, and implementation procedure.
Dear Shivani,
please share your schematic with voltage levels and part values. Please answer application engineer questions.
DESCRIPTION
1. Which register has customer modified?
2. Does other features can be behaviored?
3. Do you have customer's detailed connection and check whether PF5020 is in TBB mode.
Please let customer change the 0x71 address.
With Best Regards,
Jozef
Dear Jozef,
Thank you for your previous response and the guidance provided.
I have configured the LDO regulator as per your instructions for an output voltage of 2.8 V and set up the corresponding power-up sequence. However, the output voltage is still not reflecting on the LDO output pin.
Could you please advise what additional checks or configurations might be required to ensure the LDO output becomes active?
I would also appreciate if you could confirm whether any specific dependencies such as VSNVS, OTP_PWRON_MODE, or TBB mode settings could affect the LDO operation. full complete configuration of the LDO with 2.8 output.
Thank you for your continued support.
Best regards,
Shivani e.
Dear Shivani,
please see below an answer from the application engineer. Please try the suggested and see if it helps.
DESCRIPTION
Please let customer to check and follow the section 7.2 in the UM11360, to check again. And please make sure customer will modify the functional registers after powerup.
With Best Regards,
Jozef
Dear Jozef,
Thank you for your response and for forwarding my issue to the application team.
I appreciate your support and will wait for their feedback.
Dear Shivani,
please see below an answer from the application engineer. Please try the suggested and see if it helps.
DESCRIPTION
Please let customer to check and follow the section 7.2 in the UM11360, to check again. And please make sure customer will modify the functional registers after powerup.
With Best Regards,
Jozef
Dear Shivani,
I have contacted an application team for advise on your issue. As soon as I receive an answer, I will definitely reply to you.
Thank you for your patience.
With Best Regards,
Jozef
Dear jozefkozon,
Thank you for your response.
We are providing 5V at the LDO1IN pin in Regulator mode (1.5 V–5.0 V programmable).
and we would like to configure the LDO1 output to 2.8V. Could you please share the sequence or register configuration steps required to set the LDO regulator output to 1.8V in TBB mode?
Your guidance on the proper configuration procedure would be very helpful.
Best regards,
Shivani e.
Dear Shivani,
- The PF5020 LDO1 can operate in two modes:
- Regulator mode (1.5 V–5.0 V programmable).
- Load switch mode (output follows input).
- If the OTP/TBB configuration currently sets LDO1 as a load switch, writing the RUN voltage register will not affect the output—it will always pass through the input voltage (≈5 V). If the output voltage stays slightly lower than the input voltage (5V in your case), then the LDO1 is in load switch mode.
Please share your schematic with voltage levels and part values.
Please make sure, that the EN4 pin is pulled high.
Recommended Register Sequence (I²C)
- Set LDO1 mode to regulator (disable load switch).
- Write desired voltage (1.8 V) to the LDO1 RUN voltage register.
- Enable LDO1:
- Set the RUN bit in the LDO1 control register.
- Confirm via PGOOD4 that LDO1 is active.
With Best Regards,
Jozef
Dear jozefKozon,
Thank you for your response.
Just to clarify, the input voltage we are providing to LDO1IN is 5 V, and we want the LDO1 output to be 1.8 V.
Please let us know if there are any additional configurations or register settings required to achieve this output in our TBB mode setup.
Best regards,
Shivani e.
Dear Shivani,
please share your schematic with voltage levels and part values.
Please make sure, that the EN4 pin is pulled high.
What is the required LDO1 output voltage? What is the voltage supplied to the LDO1IN?
With Best Regards,
Jozef