Something about Digital to Analog Converter

[cyw1984]

I am used a AD5678 -2 (16 bit 2.5V internal Ref) DAC

http://www.analog.com/UploadedFiles/Data_Sheets/102142943AD5678_a.pdf

**broken link removed**
When I put all 0 in the DAC...It still occurs 0.002V
How can I reduce the output noise and solve the zero code error???
Please give a suggest....Thanks

 

[IanP]

I can see two possible reasons for not having 0V at the outputs:

- zero-scale error --> ( fig.18 in the data sheet ) gives you the output voltage error of ≥0.5mV, depending on temperature ..

- "Ground Reference Point for All Circuitry on the Part", which is pin labelled GND;
this pin has to be used as 0V reference for all outputs, and any measurement should be refered to this pin ..

So in conclusion, if you have an error of ≈1mV, or less, you will have to leave with it as it looks it will be always there ..

Regards,
IanP

 

[cyw1984]

I can see two possible reasons for not having 0V at the outputs:

- zero-scale error --> ( fig.18 in the data sheet ) gives you the output voltage error of ≥0.5mV, depending on temperature ..

- "Ground Reference Point for All Circuitry on the Part", which is pin labelled GND;
this pin has to be used as 0V reference for all outputs, and any measurement should be refered to this pin ..

So in conclusion, if you have an error of ≈1mV, or less, you will have to leave with it as it looks it will be always there ..

Regards,
IanP

Yes,
I knew that the IC has a zero code error,the data sheet is said about 0.5mVpp
but, I had an error over then 2mV

Besides,the reference gound is common with the all circuity ground
How to solve it~~~Please~~~

 

[Davood Amerion]

datasheet:

 

[IanP]

Try to use CLR (pin 9) with Clear Code Register bits CR1 and CR0 ( Table 13. and 14. ) to find out whether this error is present for 0000h (CR1=0, CR0=0), 8000h (CR1=0, CR0=1) and FFFFh (CR1=1, CR0=0), and if it is, you may try to add -2mV offset ..

Regards,
IanP

 

[cyw1984]

I can see two possible reasons for not having 0V at the outputs:

- zero-scale error --> ( fig.18 in the data sheet ) gives you the output voltage error of ≥0.5mV, depending on temperature ..

- "Ground Reference Point for All Circuitry on the Part", which is pin labelled GND;
this pin has to be used as 0V reference for all outputs, and any measurement should be refered to this pin ..

So in conclusion, if you have an error of ≈1mV, or less, you will have to leave with it as it looks it will be always there ..

Regards,
IanP

Yes,
I knew that the IC has a zero code error,the data sheet is said about 0.5mVpp
but, I had an error over then 2mV

Besides,the reference gound is common with the all circuity ground
How to solve it~~~Please~~~

I had an error over then 20mV <----CORRECTION

Added after 1 minutes:

Try to use CLR (pin 9) with Clear Code Register bits CR1 and CR0 ( Table 13. and 14. ) to find out whether this error is present for 0000h (CR1=0, CR0=0), 8000h (CR1=0, CR0=1) and FFFFh (CR1=1, CR0=0), and if it is, you will need to add -2mV offset ..

Regards,
IanP

how to add -20mV offset...??? Thanks~~

Added after 29 minutes:

How to reduce the output nosic?

 

[moreaniruddha]

I also using AD5678.. If u know the how to set its register to operate properly.. Please reply me....
I also try to set register.. here I set First reference register for internal as well as for external voltage.
then I am sending data + channel no. + Command to write & update... but it sometime work & sometime not.. If any one know the solution reply me..