These DACs use a double buffered, 3-wire serial interface that is compatible with SPI, QSPITM, MICROWIRETM, and most DSP interface standards. In addition, a serial data out pin (SDO) allows for daisy-chaining when multiple packages are used. Data readback allows the user to read the contents of the DAC register via the SDO pin. On power-up, the internal shift register and latches are filled with 0s and the DAC outputs are at zero scale.