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The typical gain error of the PGA2320 at Gain setting of 31.5dB is approximately ±0.1dB on the frequency range of 20Hz -20kHz; please note this is not a maximum guaranteed specification. In the application, you are measuring -0.131dB; which is close to the expected typical gain error specification.
When calculating the gain error, are you measuring both the input signal and output signal right at the input pins and output pins of the PGA2320 amplifier for each frequency and gain setting? This will ensure you remove any effects ofother components in your circuit.
Hi, Luis Chioye
Thank you for answer.
I know what's on the datasheet. If my gain accuracy calculation is wrong, there should be an error at 0dB.
Therefore, the gain error calculation is not wrong and it will not be affected by other circuits.
If the measurement data or the part of the data sheet does not specify the part where the error may occur as the gain increases, the user will ask about what to see and select.
Unfortunately, I do not have data immediately available of the gain error at 30dB vs frequency; this device was developed in 2004.
I will continue search for data, and also look into performing bench measurements using the Audio Precision. It will take a couple of days and have the bench system setup in place. I expect to have data by early/mid next week.
Measured the Gain Error of a fresh sample of the PGA2320 with Gain = 0dB and Gain =30dB at a few points between 100Hz and 5-kHz.The input signal was Vin=6-Vrms for Gain=0dB, and Vin=0.1892-Vrms for Gain=+30dB. The gain error measurements were made using the Audio Precision AP555.
The frequency response at Gain=0dB looks almost flat, and at Gain=30dB there is a subtle attenuation as frequency increases; although the attenuation is small, a -0.030dB change in gain error from 100Hz to 5-kHz at G=30dB for both channels. Verified the input signal amplitude and output signal amplitude at each frequency right at the inputs/outputs of the PGA2320.
Please see below.