AnsweredAssumed Answered

AD9640 output test mode.

Question asked by williamchen on Jul 18, 2011
Latest reply on Jul 21, 2011 by williamchen

Dear all,


Please help me.


First, I use DRVDD = 1.8V, differential clock input, and the output test mode is OK.

Then I swith to use DRVDD = 3.3V, single end clock input.

The SPI read is OK, and I can read out Chip ID (address 0x01)

But when I try output test mode, outputs are all high.


I'm wondering if the clock is not accept by AD9640, so please check the clock waveform for me.


Datasheet reference design:




Our design:



The waveform of point A is:




And the waveform of point B is:





At point B,

(1) Low level is 480mV, high level is 1.88V.

(2) Vpp is 2.02V

(3) Duty cycle is 49.59%

(4) Vrms is 1.407V





Is the clock not good or there may be other mistakes?

Please give me a direction to debug.

Thank you!


Best Wishes,