Volume control w/ digital potmeter

borges · 16th May 2006, 12:22 PM

For a new DAC project I plan to integrate digital X-over and volume control. With four DAC channels I'll be able to make stereo differential OR stereo single-ended bass/treble. For both these use cases I will need volume control.

One question that comes up naturally is how good are digitally controlled potmeters.

I know that Cirrus has a component named CS3318. They cite a dynamic range of 127dB and a THD+N of -110dB. This component looks like a non-inverting op-amp circuit with the (+) node connected to a tapered resistor ladder between Vin and Gnd, and the (-) node connected to another tapered resistor ladder between Vout and Gnd.

I am very keen on getting in touch with anyone with experience in using this or similar devices. How do they sound?

Cheers,
Børge

maxro · 16th May 2006, 09:00 PM

Um, you might want to try asking in the digital forum.

Leolabs · 17th May 2006, 02:32 AM

Try products from Maxim/Dallas Semiconductor.

rfbrw · 17th May 2006, 02:48 AM

Quote:

Originally posted by borges
One question that comes up naturally is how good are digitally controlled potmeters.

Take a look at the Wolfson WM8816. It is similar to the CS331X devices but the opamp is external.

borges · 18th May 2006, 10:49 AM

The WM8816 runs from a single +5V supply. But the input I will give it is a signal centered around 0V. Do you know if this will still work with the structure of the WM8816?

For the voltage swing to be larger than the supply of the WM8816 I suspect that LIN, RIN, LFO, and RFO do not have overvoltage protection that limit them between 0V and 5V.

Have you used this part in a design?

Cheers,
Børge

rfbrw · 18th May 2006, 12:01 PM

The datasheet states it will accept input signals up to +/- 18v but if that is an issue the TI PGA2310/20 devices run on +/- 15v rails. The TI devices are similar to the CS331x devices with the 2310 being pin compatible with the CS3310.

Haven't used the WM8816. About to use the CS3310.

16th May 2006, 12:22 PM	#1
borges diyAudio Member Join Date: Dec 2003 Location: Oslo, Norway	Volume control w/ digital potmeter For a new DAC project I plan to integrate digital X-over and volume control. With four DAC channels I'll be able to make stereo differential OR stereo single-ended bass/treble. For both these use cases I will need volume control. One question that comes up naturally is how good are digitally controlled potmeters. I know that Cirrus has a component named CS3318. They cite a dynamic range of 127dB and a THD+N of -110dB. This component looks like a non-inverting op-amp circuit with the (+) node connected to a tapered resistor ladder between Vin and Gnd, and the (-) node connected to another tapered resistor ladder between Vout and Gnd. I am very keen on getting in touch with anyone with experience in using this or similar devices. How do they sound? Cheers, Børge

16th May 2006, 09:00 PM	#2
maxro diyAudio Member Join Date: Dec 2004 Location: Survey says: Least happiest city in Canada	Um, you might want to try asking in the digital forum. __________________ "Part of the reason a poot into a toilet bowl sounds the way it does is because of phase shift." -Andrew Eckhardt

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17th May 2006, 02:32 AM	#3
Leolabs diyAudio Member Join Date: Dec 2004 Location: Bukit Mertajam	Try products from Maxim/Dallas Semiconductor.

18th May 2006, 10:49 AM	#5
borges diyAudio Member Join Date: Dec 2003 Location: Oslo, Norway	The WM8816 runs from a single +5V supply. But the input I will give it is a signal centered around 0V. Do you know if this will still work with the structure of the WM8816? For the voltage swing to be larger than the supply of the WM8816 I suspect that LIN, RIN, LFO, and RFO do not have overvoltage protection that limit them between 0V and 5V. Have you used this part in a design? Cheers, Børge

18th May 2006, 12:01 PM	#6
rfbrw diyAudio Member Join Date: Oct 2001 Location: .	The datasheet states it will accept input signals up to +/- 18v but if that is an issue the TI PGA2310/20 devices run on +/- 15v rails. The TI devices are similar to the CS331x devices with the 2310 being pin compatible with the CS3310. Haven't used the WM8816. About to use the CS3310.

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