PCM1773: Offset voltage on "0x0000"

Kuramochi Tadahiko

Guru 28715 points

Part Number: PCM1773

Hi,

Offset voltage is observed on only 0x0000 as below.

Is this offset voltage unavoidable phenomenon?

And does "Bipolar zero error" specified on the datasheet mean this offset voltage?

Best Regards,

Kuramochi

over 7 years ago

0 Paul_Frost over 7 years ago

TI__Guru 55743 points

Hi Kuramochi-san,

The bipolar zero error can be thought of as an offset to the entire output, as the center voltage should be ~0.5×VCC. Note that this voltage would also be impacted by any offset or ripple in the VCC supply as well. Is VCC will regulated and constant?

I am not sure if this offset is unavoidable, as we do not specify linearity for our audio DACs.

Thanks!
Paul

0 Kuramochi Tadahiko over 7 years ago in reply to Paul_Frost

Guru 28715 points

Paul-san,

Thank you for your help.
I understood about bipolar zero error.

Is this offset caused by the structure of PCM1773? or variation of individual samples?
If the structure of PCM1773 is, we avoid to use "0x0000" data.

Best Regards,
Kuramochi

0 Paul_Frost over 7 years ago in reply to Kuramochi Tadahiko

TI__Guru 55743 points

Hi Kuramochi-san,

How are you measuring this? What is the offset for the negative codes?
-1 (0xFFFF)
-2 (0xFFFE)
-3 (0xFFFD)

Thanks!
Paul

0 Paul_Frost over 7 years ago in reply to Paul_Frost

TI__Guru 55743 points

Hi Kuramochi-san,

Any updates?

Thanks!
Paul

0 Kuramochi Tadahiko over 7 years ago in reply to Paul_Frost

Guru 28715 points

Paul-san,

Thank you for your reminding.
My customer is confirming.
Just a moment, please.

Best Regards,
Kuramochi

0 Kuramochi Tadahiko over 7 years ago in reply to Kuramochi Tadahiko

Guru 28715 points

Hi Paul-san,

I discussed with my customer.
I had misunderstood this problem, I'm sorry.
I posted different question to follow link.
e2e.ti.com/.../726207
Could you help it?

Best Regards,
Kuramochi

Audio

Audio forum

PCM1773: Offset voltage on "0x0000"