The AD57901 is a single 20-bit， unbuffered voltage-output DAC that operates from a bipolar supply of up to 33 V. The AD5790 accepts a positive reference input in the range of 5 V to VDD ? 2.5 V and a negative reference input in the range of VSS + 2.5 V to 0 V. The AD5790 offers a relative accuracy specification of ±2 LSB maximum range， and operation is guaranteed monotonic with a ?1 LSB to +3 LSB DNL specification. The part uses a versatile 3-wire serial interface that operates at clock rates of up to 35 MHz and is compatible with standard SPI， QSPI?， MICROWIRE?， and DSP interface standards. Reference buffers are also provided on chip. The part incorporates a power-on reset circuit that ensures the DAC output powers up to 0 V in a known output impedance state and remains in this state until a valid write to the device takes place. The part provides a disable feature that places the output in a defined load state. The part provides an output clamp feature that places the output in a defined load state.