The LTC2657 is a family of octal I2C 16-/12-Bit Rail-to- Rail DACs with Integrated 10ppm/°C Max Reference. The DACs have built-in high performance, rail-to-rail, output buffers and are guaranteed monotonic. The LTC2657-L has a full-scale output of 2.5V with the integrated reference and operates from a single 2.7V to 5.5V supply. The LTC2657-H has 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 full-scale output to 2 times the external reference voltage. The parts use a 2-wire I2C compatible serial interface. The LTC2657 operates in both the standard mode (maximum clock rate of 100kHz) and the fast mode (maximum clock rate of 400kHz). The LTC2657 incorporates a power-on reset circuit that is controlled by the PORSEL pin. If PORSEL is tied to GND the DACs reset to zero-scale at power-up. If PORSEL is tied to VCC, the DACs reset to mid-scale at power-up.
