The 3-wire serial interface is compatible with SPITM, QSPITM, and MICROWIRETM standards. An input register followed by a DAC register provides a double-buffered input, allowing the input and DAC registers to be updated independently or simultaneously with a 16-bit serial word. Additional features include software and hardware shutdown, shutdown lockout, a hardware clear pin, and a reference input capable of accepting DC and offset AC signals. These devices provide a programmable digital output pin for added functionality and a serial-data output pin for daisy-chaining. All logic inputs are TTL/CMOScompatible and are internally buffered with Schmitt triggers to allow direct interfacing to optocouplers. The MAX5171/MAX5173 incorporate a proprietary on-chip circuit that keeps the output voltage virtually "glitch free," limiting the glitches to a few millivolts during power-up. Both devices are available in 16-pin QSOP packages and are specified for the extended (-40C to +85C) temperature range. The MAX5171/MAX5173 are pin-compatible upgrades to the 12-bit MAX5175/MAX5177. For 100% pincompatible DACs with an internal reference, see the 13-bit MAX5132/MAX5133 and the 12-bit MAX5122/MAX5123 data sheets.