12-bit R-2R DAC with a 1 µs settling window
The MAX543BCSA+T is a 12-bit multiplying DAC built on a classic R-2R ladder architecture, delivering a current-unbuffered output that settles in 1 µs. The SPI data interface keeps the pin count low — three wires (data, clock, chip-select) carry the conversion word, which fits a standard MCU SPI port without level-shifting gymnastics. The current-unbuffered output is the raw R-2R ladder current — no internal op-amp. This means the output impedance is code-dependent, and the load must be an external op-amp configured as a transimpedance amplifier (or a resistor to ground for a voltage output with known scaling). The advantage: the user controls the gain and the output swing, and the DAC's linearity is not compromised by an internal buffer's offset or drift.
Supply rails and temperature envelope
The DAC operates from dual supplies: a 5 V rail and a higher-voltage rail from 11.4 V to 15.75 V, with both analog and digital supplies sharing the same voltage range. The 5 V rail typically powers the digital interface and the R-2L ladder reference; the higher rail sets the output compliance range for the current output. INL and DNL are both specified at ±1 LSB maximum — this is a 12-bit accuracy spec that guarantees monotonicity over temperature. A ±1 LSB DNL means no missing codes, which is the minimum requirement for a DAC in a closed-loop control or precision voltage-source application.