digital volume pot ic

[Bengali]

Hi,

I'm working with a Maxim 5456 10K digital pot.

Everything is functional however I'm getting major
distortion in the audio.

I'm wiring it in place of a standard pot, H end (input),
Wiper(output), L end to GND. it's between the cd player's
output and a preamp.

any suggestions as to what I may be doing wrong?

thanks

 

[paulb]

You probably need an op-amp buffer as it shows in the data sheet.

 

[Bengali]

thx. guess I will try an op amp next.

do you know why they have the low end tied to Vdd/2, half of Vdd? instead of to Gnd? this wiring is for their headphone amp.

 

[paulb]

It's because it is a single-supply device and the signal has to be referenced to a point in the middle of the supply voltage so the device can swing above and below it. This is similar to using an op-amp with a single supply voltage: you need a reference voltage somewhere in the middle. You're probably hearing what it sounds like with only the positive swings. clipping everything below 0.

 

[Bengali]

ah! makes sense. thanks. will proceed with an op amp.