Part Number: DAC5670
Hi,
I'm having trouble with DAC5670 device.
The amplitude of output signal does not match the input code.
And I can't get large enough output signal whatever code I input to the DAC.
To separate this issue from any other possible sources, I did the following:
- I designed 2 registers in the FPGA and connected each register's output to DA bus and DB bus.
- If I write value_A to register A and value_B to register B, then the input code to the DAC should be alternating value_A and value_B. (value_A,value_B,value_A,value_B,...)
- By doing this, I can ignore the setup/hold timing issue of DA, DB input bus.
Then I tried to write the registers as following steps:
1. value_A = 0x0, value_B = 0x0001
2. value_A = 0x0, value_B = 0x0002
3. value_A = 0x0, value_B = 0x0004
4. value_A = 0x0, value_B = 0x0008
5. value_A = 0x0, value_B = 0x0010
6. value_A = 0x0, value_B = 0x0020
7. value_A = 0x0, value_B = 0x0040
8. value_A = 0x0, value_B = 0x0080
9. value_A = 0x0, value_B = 0x0100
10. value_A = 0x0, value_B = 0x0200
11. value_A = 0x0, value_B = 0x0400
12. value_A = 0x0, value_B = 0x0800
13. value_A = 0x0, value_B = 0x1000
14. value_A = 0x0, value_B = 0x2000
15. value_A = 0x0, value_B = 0x3FFF
In my opinion the output signal should be doubled as the above test proceeds, but it isn't.
The output signal gets larger until value_B=0x0100. But things are getting strange from the following steps.
When value_B=0x0200, the output signal becomes as small as the signal when value_B=0x0020.
When value_B=0x0400, the amplitude is the same when value_B=0x0040.
When value_B=0x0800, the amplitude is the same when value_B=0x0080.
When value_B=0x1000, the amplitude is the same when value_B=0x0100.
I have double-checked the pin assignment of the schematic and FPGA constraint many times.
There are 2 DACs on each board, and we have 4 boards so there are 8 DACs on our hand, and all 8 DACs have the same issue.
Do you have any idea to solve this problem?
FYI, the datasheet I have is (
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