Hi,
When I program AD5764R to give an output it gives an -1,4V offset.
- This situation occurs at our 3 boards.
- At one of these boards I also changed the DAC with a new one. But situation continues.
Below picture represents my schematic. DAC is driven directly by a Spartan6 fpga with 3,3V LVDS.
((Info: R51 was also tried as floating point. Offset situation continues.))
Can any one offer me what to check or what is the reason of this -1,4V offset please?
Please check my below steps:
((Dac-A & Dac-B readings we directly done over the DAC pins. (Pin 23 & 22 respectively.))
- --- power up the IC.
Dac-A = 0V
Dac-B = 0V
On the SDIN pin no signal came.
- --- Send 0x010001 to program function register.
Dac-A = 0V
Dac-B = 0V
On the SDIN pin 0x010001 signal was seen. - --- Send 0x1C0000
Dac-A = -1,4V
Dac-B = -1,4V
On the SDIN pin 0x1C0000 signal was seen. - --- Send 0x240000
Dac-A = -1,4V
Dac-B = -1,4V
On the SDIN pin 0x240000 signal was seen. - --- Send 0x2C0000
Dac-A = -1,4V
Dac-B = -1,4V
On the SDIN pin 0x2C0000 signal was seen.
- --- Send 0x110FFF
Dac-A = -1,4V
Dac-B = 0 V - --- Send 0x110000
Dac-A = -1,4V
Dac-B = -1,4V - --- Send 0x11FFFF
Dac-A = -1,4V
Dac-B = -1,4V - --- Send 0x11EEEE
Dac-A = -1,4V
Dac-B = -2,9V - --- Send 0x11DDDD
Dac-A = -1,4V
Dac-B = -4,3V - --- power down.
Best regards,
Sercan
