AD9117 DAC Reset Issue

Hi Arumugam2608 ,

500us reset pulse should be enough duration to reset the registers to their default values, but can you check if you providing the right reset pulse to the RESET/PINMD (pin 35)? The pulse will depend which mode you are in: SPI mode or PIN mode. Please refer to page 52 of the AD9117 datasheet. 

Also, are you using the AD9117 evaluation board? If not, can we get a copy of your board schematic? Just so we could check if your power supply (AVDD, CVDD, DVDDIO, DVDD) are within operating conditions, as well as the DAC connections. 

Hi Arumugam2608 ,

500us reset pulse should be enough duration to reset the registers to their default values, but can you check if you providing the right reset pulse to the RESET/PINMD (pin 35)? The pulse will depend which mode you are in: SPI mode or PIN mode. Please refer to page 52 of the AD9117 datasheet. 

Also, are you using the AD9117 evaluation board? If not, can we get a copy of your board schematic? Just so we could check if your power supply (AVDD, CVDD, DVDDIO, DVDD) are within operating conditions, as well as the DAC connections. 

Hi JMMina,

Thank you for your reply.

We don't have AD9117 evaluation board.

We are using SPI mode.

Please find the AD9117 DAC connection.

Thanks&Regards,

Arumuga Raj S

Hi JMMina,

Herewith, I have attached the DAC power supply vs reset pulse images,please provide suggestion.

Also, Provide the SPI timing diagram. This will help us for further analysis.

Thanks&Regards,

Arumuga Raj S

Hi Arumugam2608 :

Apologies for the delayed response. SPI timing diagram can be found in page 35 of the datasheet. For the pulse images, can you provide the full length of the RESET pulse (green trace)? Pin 35 must be pulled low to DVSS to choose SPI mode, afterwards you provide the pulse width of 50 ns (minimum) to reset the SPI registers to their default values. In your case, please ensure that you set the pin low again after the 500us reset pulse.

Can you provide the register addresses/values that you are reading? They should follow the default SPI register values indicated at page 36 of the datasheet.

Regards,

Marco

Hi JMMina,

We need SPI Write and Read timing diagram,In datasheet mentioned as write and read sequence.

Initially we are given to 500us reset pulse. At that time
DAC register randomly jump to junk values(odd registers 0x0A & 0xFF, even registers 0).

We followed below mentioned sequence

Still DAC registers jump to Junk values(randomly).

Please provide the valuable solution.

Thanks&Regards,

Arumuga Raj S

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