AFE5818: inverted analog signal

Vassili Ivanov40

Part Number: AFE5818
Other Parts Discussed in Thread: AFE5851

I am getting correct polarity of test signals out of AFE5818, but inverted polarity of analog signals sent to the analog inputs. I could not find in the datasheet if LNA or PGA are inverting the signal. Please let me know if LNA or PGA of AFE5818 are inverting the signal?

A similar question was raised about AFE5851, and the answer was the signal was inverted by VCA for AFE5851 (but I still cannot find reference in the datasheet about it). e2e.ti.com/.../1735291

over 6 years ago

0 Praveen Aroul over 6 years ago

TI__Mastermind 49986 points

Vassili,

I will check with the team and will be able to get back to you by mid next week.

0 Xiaochen (Sean)Xu over 6 years ago in reply to Praveen Aroul

TI__Expert 6040 points

vassili,

based on my knowledge, we didn't expect inverted signal. of course, Praveen will confirm it in the lab.

the test is the burst signal. this way, we can monitor the starting phase of the burst signal on the function generator vs. AFE output.

Thanks!

Xiaochen

0 Vassili Ivanov40 over 6 years ago in reply to Xiaochen (Sean)Xu

Prodigy 220 points

Xiaochen, my test signal was a short positive pulse from a signal generator, which I got inverted.

0 Xiaochen (Sean)Xu over 6 years ago in reply to Vassili Ivanov40

TI__Expert 6040 points

it is indeed inverted from out lab. your finding is correct. there is a bit in the register to invert the LVDS output, it can help , like Reg.24 36[0:3] etc.

Thanks!

0 Vassili Ivanov40 over 6 years ago in reply to Xiaochen (Sean)Xu

Prodigy 220 points

Thank you for confirmation. To me it is not important if the signal inverted or not. I just need it to assure that I do non have bugs on my side.

Please add signal inversion as a feature to AFE5818 datasheet.

0 Xiaochen (Sean)Xu over 6 years ago in reply to Vassili Ivanov40

TI__Expert 6040 points

Noted. Thanks! we will do in next datasheet update.

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AFE5818: inverted analog signal