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Question asked by 林一凡 on May 23, 2018
Latest reply on Jun 4, 2018 by 林一凡


About AD9910 Abnormal Power Technology Advisory at Low Temperature

(Help needed regarding the fault of AD9910 at power-on in low temperature condition)


(Fault description: AD9910 is used for frequency-dividing, with reference input of 480MHz, and output of 26~30MHz single tone signal. There is one fault ( with no output signal) out of 30 times at time of  power-on in low temperature-40~0℃) )


Data was sent by general SPI interface, and the timing sequence of SCLK,SDIO Vs. I/O_UPDAT is as follows:

Red is SCLK, yellow is SDIO, and green is I/O_UPDAT.   red-SCLK,

yellow-SDIO, green- I/O_UPDAT

Expanded above


watching the intersection of SCLK and I/O_UPDAT


question 1: Is the parameter setting-up of  SCLKSDIO Vs. I/O_UPDAT is correct as being shown above


when the timing sequence was changed as being shown followed, there was no fault at time of power-on in low temperature.

Yellow is SCLK and green is I/O_UPDAT.  
yellow--SCLK, green--I/O_UPDAT
Set I/O_UPDAT high after clock completes 2 cycles

Once the I/O_UPDAT was set to high after 2 periods of SCLK, there was no fault at time of power-on in low temperature.  our second question was: is there a delay required for I/O_UPDAT regarding SCLK signal? if yes, how to set up the time delay?