AD5316R external reference not working.

Hello All,

we are using DAC AD5316R. The Vref is 3.3v

First I perform a software reset with the command 0x60 and then disable the internal reference with the command 0x70 with setting the DB0 as 1.

with this, i expect that the DAC starts using the external Vref 3.3v

so when a digital value of 1023 is sent to a particular channel, then i expect a output voltage of 3.3v.

But, when i write a 1023 digital value, I get only 2.5v

NOTE: The 3.3v to Vref is provided via 1k ohm resistor.