AWR1642: radar

user1454792

Part Number: AWR1642

One of the metrics of the RF specification of AWR1642 is -90dBFS of Idle Channel Spurs. What does Idle Channel Spurs mean? How does the design guarantee? such as digital and analog ground isolation.

over 5 years ago

0 Vivek Dham over 5 years ago

TI__Guru 58035 points

Hello,
Idle channel spur is defined as the spur level in the RX spectrum with TX turned OFF (no external signal level seen on the RX pin). This spec helps define if there are any spurs in the RX chain itself (like ADC etc.)

Regards,
vivek

0 user1454792 over 5 years ago in reply to Vivek Dham

Prodigy 240 points

Hello，Integration of AWR1642 is very high.How to ensure digital circuit and analog circuit isolation? Reference AWR1642 evaluation board,only power isolation is done, but ground is not done. Now ,reference AWR1642 evaluation board,switch frequency leaks to ADC.

0 Vivek Dham over 5 years ago in reply to user1454792

TI__Guru 58035 points

Hello ,
Which switch frequency are you seeing leaking to the ADC? Could you provide more details?

Regards,
Vivek

0 user1454792 over 5 years ago in reply to Vivek Dham

Prodigy 240 points

LP87524 switch frequency leaks to the ADC.There is a 4MHz spurious after FFT of ADC data.

0 Vivek Dham over 5 years ago in reply to user1454792

TI__Guru 58035 points

Is it seen on the TI EVM or your own board?

Regards,
Vivek

0 user1454792 over 5 years ago in reply to Vivek Dham

Prodigy 240 points

Our board

0 Vivek Dham over 5 years ago in reply to user1454792

TI__Guru 58035 points

Hello,
This seems to be external coupling from the PMIC to the AWR device . The PMIC needs to be properly isolated from the AWr device to avoid coupling of the switching frequency. All critical nodes on the AWr device need to be shielded from the switcher, like the XTAL pins, 1V4 APLL, 1V4 SYNTH , BGAP etc. Its recommended to place the switcher as far as possible from the AWr device and preferably on the opposite side to minimize coupling.

Regards,
Vivek

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AWR1642: radar