A third application where DAC linearity plays an important role is “Set and Forget” systems. In such a system, an adjustment or calibration is made once, perhaps at the time of manufacture or during installation. So this system starts life as a closed loop system, and then goes open loop. Thus, any parameter related to initial accuracy (offset, gain error, INL) is not critical, as it is compensated for during the adjustment. But once the feedback is removed, stability becomes key. Datasheet specifications that indicate stability are gain error drift, offset drift, and reference drift. In this example, the LTC2751 16-bit current output DAC sets the bias for an open loop. The LTC2751 includes an offset adjust pin that lets a customer make very fine adjustments to the offset of the LTC2751’s DAC output. The 12-bit LTC2630 DAC, along with the LT1991 programmable gain amplifier, adjusts the voltage on the LTC2751’s ROFS pin for fine tuning of the LTC2751 offset voltage. After setting the LTC2751 and LTC2630 DAC outputs just once, the system codes can be programmed into memory to power up to the same adjusted voltage every time, allowing the customer to “forget” about having to adjust the DACs any further.