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ad9835 shows 0 volt

Question asked by vanashree on Oct 2, 2013
Latest reply on Oct 7, 2013 by musach

hello everybody,

i have bought AD9835 and made the connections as per the datasheet and my circuit diagram is attached herewith.

i get 0 volts at the output when i connect 300 ohms resistance to Iout and AGND and see the voltage its 0 volts.

my MCLK = 25Mhz , SCLK = 100 Hz (TTL compatible), FSYNC = 16msec low signal because SCLK is 100 Hz and 16 bits are to be transmitted so when transmission of 16 bits begin FSYNC goes low and after 16 bits transmission is  finished FSYNC goes low (these are timed signals so care is taken that FSYNC stays low upto complete transmission is finished) , SDATA = 16 bit binary word

I have connected AGND and DGND at one point.

AVDD = 5v regulated from 7805

DVDD =5v from power supply,

PSEL0, PSEL1, FSELECT are grounded (as per datasheet to use these from bit these pins are to be grounded)

I have attached my circuit diagram herewith kindly go through it

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