PCM4220: Dynamic range calculation

Marvn Arcangel

Genius 15420 points

Part Number: PCM4220

Hi Team,

A customer would like to know how the dynamic range is calculated.

At 192kHz the Dynamic range is specified as 112dB. What is the voltage on VCOML and VCOMR and what is the RMS noise?

In the past, the customer used this formula: Dynamic Range = 20*Log(Vref-RMS/Noise-RMS) dB

Assuming the reference voltage is 4V then is the Noise-RMS = (4/sqrt2)/10^(112/20) = 7.1uVRMS

Is this correct? Can you help clarify?

Thank you.

Regards,

Marvin

0 Sanjay Dixit over 3 years ago

shall reply in a few hours.. Thank you

0 Marvn Arcangel over 3 years ago in reply to Sanjay Dixit

Hi Sanjay,

Thank you. I shall wait for your response.

Regards,

Marvin

0 Sanjay Dixit over 3 years ago in reply to Marvn Arcangel

VCOML and VCOMR Have a DC Voltage 0.4875*Vcc1 and 0.4875*Vcc2

My first thoughts on Dynamic Range. Please let me know if you agree with this.

Dynamic Range=20*Log(Vlargest signal/Vsmallest signal)

Vlargest is 5.6Vpp differential.

Vsmallest is the level at which SNR=1.

112db=20*Log(5.6Vpp/Vsmallest)

112/20=Log(5.6Vpp/Vsmallest)

398107=5.6Vpp/Vsmallest

Vsmallest=5.6Vpp/398107

Vsmallest=14uvpp

Vsmallest(rms) differential = 14uv/2*1.414 4.9uv rms which would be the noise level

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