I have use AD5541A ( 16 bit DAC ) for a while and have very good use experience with AD5541A.
now I hope to try their family which is enhance to 18 or 20 bit DAC, that is AD5791.
unfortunately AD5791's positive reference voltage is recommend to operate with 5.0V ~ ( VDD - 2.5V )
but not 2V ~ VDD such as AD5541A ( 16 bit DAC )..
is there have another choice can meet my hope ? thank you!
My hope are list below:
1. VREFp : 2V ~ ( VDD - 2.5V )
2. 18 or 20 bit ( 18 bit may better )
3. un-buffer voltage output
thank you for help!
May I know what your target output voltage range is? and what is your application wherein you would need the 18/20-bit resolution?
The target output voltage range is 1.6 ~ 15V and my application are trying to
1. build a high accuracy Voltage reference with wide range
2. build a 16 bit ADC test environment
thanks for help!
Just to clarify, will you be using the DAC as the high voltage reference to your ADC?
If this is the case, you will need to vary the reference input on the AD5791 to cater to the ADC. Using a single reference to the AD5791 will not be applicable to all ADC conditions.
For example, when you need a 1.6V as reference, you could use a 5V reference to the AD5791 and the INL error will only be 5/2^20 = 4.77uV. This is less than the LSB of the ADC which is 1.6/2^16 = 24.41uV.
If you need 15 as the reference, you can use a 15V reference to the AD5791. INL will be 15/2^20 = 14.31uV. This is This is also less than the LSB of the ADC which is 15/2^16 = 228.89uV.
Thanks for sharing your comment,
I'll try to use a LDO with variable resistance to vary my reference input on the AD5791,
since LTZ1000, LTC6655 & ADR445 are hard to vary their output voltage.
But if AD5791's reference input can operate less than 5V ( such as AD5541A down to 2V )
This will vary helpful to me to count gain error of my ADC.
The AD5791 is specified to have a minimum of 5V at the reference input. Specifications and operation are not guaranteed outside this range.
You could check out LT3045. It is an ultralow noise LDO which you can set the output range from 0.6V to 15V.