The AD7846 is a 16-bit DAC constructed with Analog Devices' LC2MOS process. It has VREF+ and VREF- reference inputs and an on-chip output amplifier. These can be configured to give a unipooutput range (0 V to +5 V, 0 V to +10 V) or bipolar output ranges (±5V, ±10 V). The DAC uses a segmented architecture. The 4 MSBs in the DAC latch select one of the segments in a 16-resistor string. Both taps of the segment are buffered by amplifiers and fed to a 12-bit DAC, which provides a further 12 bits of resolution. This architecture ensures 16-bit monotonicity. Excellent integral linearity results from tight matching between the input offset voltages of the two buffer amplifiers.

In addition to the excellent accuracy specifications, the AD7846 also offers a comprehensive microprocessor interface. There are 16 data I/O pins, plus control lines (CS, R/W, LDAC and CLR). R/W and CS allow writing to and reading from the I/O latch. This is the readback function which is useful in ATE applications. LDAC allows simultaneous updating of DACs in a multi-DAC system and the CLR line will reset the contents the DAC latch to 00 . . . 000 or 10 . . . 000 depending on the state of R/W. This means that the DAC output can be reset to 0 V in both the unipolar and bipolar configurations. The AD7846 is available in 28-pin plastic, ceramic, LCCC and PLCC packages.