The acromag cards are configured to have ±10 V over 2^15 bits. The least significant bit (LSB) is therefore 20V/2^15 bit = 0.61 mV/bit.  For an AD590 hooked up to a tranimpedance amplifier one would select a 30.96 kΩ transresistance gain to achieve 10 V @ 50 C.  This make the total gain from temperature to volgate G_{temp to V} = 1µA/K * 30.96 kV/A = 30.96 mV/K.  The minimum possible resolution is therefore LSB/G_{temp to V} = 19.7 mK/bit.  Not great if we are going for 1mK temperature stabilization.