PCM1808 - About a power supply (VCC & VDD) sequence

Hi, Kanemaru-san,

I've asked my colleague to comment on your post.

-d2

Hi Don,

Thank you for your prompt reply.

I am looking forward to your reply.

Regards,

Kanemaru

Hi 

How Vref is stable when changing Vcc in the chip PCM1808?

Thanks

Hi Malinovskij-san,

I'm Sonoki and I word with Kanemaru in Macnica we are disty in Japan.

Today I visited customer and confirmed their question and background, so please let me ask you again.

[Their situation]

- Power up the Vcc and Vdd, and after that SCKI is input

- Vdd and SCKI are off at power down mode in their system but Vcc is kept to apply.

- Vdd and SCKI are input again when it's returned to normal operation

[Question]

1, Is the PCM1808 not damaged when Vdd and SCKI are lost? (They do not care the output at this time)

2, Can PCM1808 be operated correctly again when Vdd and SCKI are input again?

Best Regards,

Sonoki

Hi Malinovskij-san, Don-san,

We need to give our customer some comments as soon as possible. I'm waiting for your response.

Best Regards,

Sonoki

HI Ravi-san,

Thank you for your response. Please let me ask again if they have further question.

Best Regards,

Sonoki

Hi, Malinovskij,

Welcome to e2e, and thanks for your interest in our devices!

Several places in the d/s, it refers to VREF = VCC/2, so this means VREF will 100% track any changes in VCC. It is most likely generated via a resistor divider, so that output impedance of that resistor divider (unfortunately, I don't know what that is) combined with the recommended capacitor on the pin will give you some immunity to ac changes on VCC, but dc changes on VCC will cause VREF to track accordingly.

-d2