Marc_2 wrote:
It looks strange that the sum of both output voltages is not 0.96 V but rather close to 0.72 or 0.74 V.
Have you checked voltage on all pins, including supply and ground ? Is pin 17 at 1.2 V ?
I think I reported the wrong voltage on IOUTB when I have the DAC connected to the FPGA. When the FPGA is toggling the data pins (with a ramp signal) IOUTA = 700mV and IOUTB = 400mV (so roughly 1.1V).
REFIO (pin 17) = 1.2V.
Since I would like to use the internal reference voltage, REFLO is tied to ACOM.
My ground pins are measuring approx 34mV when the circuit is active.
I went back and re-measured all the pins when the data is tied all high and all low.
"1111111111" : IOUTA = 860mV, IOUTB = 300mV, REFIO = 1.3V;
"0000000000" : IOUTA = 140mV, IOUTB = 1.02V, REFIO = 1.3V;
For both, DVDD and AVDD = 3.24V. DCOM and ACOM = 34mV. REFIO = 1.2V. COMP1 = 1.6V. COMP2 = 2V. FSADJ = 1.3V.