Unless I missed an earlier post on this...
If 20 pins, maybe AD5791:
http://www.analog.com/en/digital-to-analog-converters/da-converters/ad5791/products/product.html
If 20 pins, maybe AD5791:
http://www.analog.com/en/digital-to-analog-converters/da-converters/ad5791/products/product.html