how do I know the gain of AD8338 if I set Vgain=0V?

Hello,

I will look into this. For now, may I know your required VGain?

Thanks,

Mae

The DAC output controlling Vgain in my design ranges from 0~2.5V. But after power up, the DAC has default output 0V, what happen to AD8338 at this time?

It's attenuator at this time?

HI wujianfeng ,

Here are the response for each question.

1. the Vgain values ouside of 0.1V~1.1V are not recommended for design?

- Vgain outside the preferred range is not recommended as we can see on the calculation to get 0 to 80dB range. For 0V gain, the gain would be -8db and for example of 1.2V, the gain(db) is 88dB which is out of range of the specification.

2. what's the potential issue if I set Vgain to values those are outside of  0.1V~1.1V?.

- Since the 0 to 80dB is the only tested value, we cannot expect that we can get the -8 or 88dB when we applied 0 and 1.2V Vgain values.

3. if not, how do I know the gains when Vgain is not in 0.1V~1.1V range?

- The gain can be calculated based on this formula, but still the tested range is only 0dB to 80dB range for 0.1 - 1.1V.

The DAC output controlling Vgain in my design ranges from 0~2.5V. But after power up, the DAC has default output 0V, what happen to AD8338 at this time?

With 0V gain, we can expect an attenuation in the gain if we based on the calculation and on the Vgain higher than 1.1V, it is calculated to have higher gains than 80dB but this was not tested. It is recommended to use the input voltages within the range.

Thanks and regards,

JE