The LTC2654/LTC2655/LTC2656/LTC2657 are a family of quad/octal 16-/12-bit rail-to-rail DACs with a precision integrated reference. The DACs have built-in high performance, rail-to-rail, output buffers and are guaranteed monotonic. The "-L" versions have a full-scale output of 2.5V with the integrated 10ppm/°C reference and operates from a single 2.7V to 5.5V supply. The "-H" versions have a full-scale output of 4.096V with the integrated reference and operates from a 4.5V to 5.5V supply. Each DAC can also operate with an external reference, which sets the DAC full-scale output to two times the external reference voltage. The LTC2654/LTC2656 (quad/octal) communicate via an SPI/MICROWIRE™ compatible 4-wire serial interface, which operates at clock rates up to 50MHz. The LTC2655/LTC2657 (quad/octal) communicate via an I2C interface serial interface, which operates at clock rates up to 400kHz.The DACs incorporate a power-on reset circuit that is controlled by the PORSEL pin. If PORSEL is tied to GND the DACs reset to zero-scale. If PORSEL is tied to VCC, the DACs reset to mid-scale.