AD5668 EVAL board

Hi NurEng ,

Ensure LK5 is in Position A (internal reference) and LK4 is insrted (decoupling). Verify supplies, AVDD (2.7–5.5V) and DVDD (5V) are within spec. Send 0x08000001 (DB0=1)over SPI to enable the internal reference. Measure Pin 8 (VREFOUT) / TP1 again. To update outputs, pulse LDAC low or tie it low permanently. If the issue persists, kindly send your schematics as well as EVB link settings to debug further.

Br,

Den

Hello Den,

Lk4 is inserted .

We tried LK5 both , in internal ref and external ref positions ; output remained always zero for all the commands we sent.

We have dvdd=avdd=3.3v .. is 5V mandatory for other ckts on the eval board?

I measure the voltage on the chip and verified all connections

Also levels of digital signals are ok with the oscilloscope.

Regards

Hi,

The 3.3V is within the acceptable range for the AD5668, therefore, it is perfectly fine for powering the AD5668 itself. However, some components on theeval board may require 5V for proper operation as stated on the userguide. Also, to simplify testing and rule out timing-related issues, I recommend tying the LDAC pin permanently low during your initial tests. This will ensure that the DAC outputs are updated immediately after sending the SPI command.

Are you using an external microcontroller or ADI’s SW and SDP, and could you share your complete SPI command sequence and all jumper settings so we can further diagnose your setup?

Br,

Den

Hi,

The 3.3V is within the acceptable range for the AD5668, therefore, it is perfectly fine for powering the AD5668 itself. However, some components on theeval board may require 5V for proper operation as stated on the userguide. Also, to simplify testing and rule out timing-related issues, I recommend tying the LDAC pin permanently low during your initial tests. This will ensure that the DAC outputs are updated immediately after sending the SPI command.

Are you using an external microcontroller or ADI’s SW and SDP, and could you share your complete SPI command sequence and all jumper settings so we can further diagnose your setup?

Br,

Den