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PCM1803A: Power-on/off Sequence

Sadanori Kato
Guru 36530 points
Part Number: PCM1803A
Other Parts Discussed in Thread: PCM1795, PCM1808, PCM1807

Hi,

The power-on-reset sequence is mentioned on page 10 of PCM1803A data sheet as follows. However, it isn't mentioned the relationship between VCC and VDD at power-on and power-off.
So, could you please tell me the recommended power on/off sequence for VCC and VDD?
Additionally, it isn't mentioned about /PDWN which is power-down control pin in figure 17. Could you please tell me the recommneded power on/off sequence as well if using /PDWN pin ?

Please see the related threads as follows.

PCM1803A: Power Supply Requirement
https://e2e.ti.com/support/audio/f/6/t/736015

PCM1795, PCM1808 / Power up sequence
https://e2e.ti.com/support/audio/f/6/t/251395

Best regards,
Kato

  • 0
    TI__Mastermind 23050 points

    Hi Kato-san,

    Unfortunately we don't have a lot of information on this functionality outside of what exists in the datasheet but the power sequencing requirements for this family are not very strict. This device was developed around the same time as the PCM1807/8 devices so I believe it would fall under specification 2 in the document found in your linked thread. If you wanted to design conservatively though then you could assume it is specification 1 and that the rails should be kept within 3V of each other during startup.

    Best,

    Zak

  • 0 in reply to Zak Kaye
    Guru 36530 points

    Hi Zak-san,

    Thank you for the information.

    I just found the following thread. So, I will suggest our customer that the voltage difference between VCC and VDD including power supply on/off transient must be less than 3.0V.

    PCM1803A: Vcc ⁄ Vdd Internal equivalent circuit
    https://e2e.ti.com/support/audio/f/6/p/737378/2726673#2726673

    Best regards,
    Kato