The XR16M27511 (M2751) is a high performance dual universal asynchronous receiver and transmitter (UART) with 64 byte TX and RX FIFOs. The device operates from 1.62 to 3.63 volts and is pin-to-pin and software compatible to Exar's XR16V2751. The device includes 2 additional capabilities over the XR16M2750: Intel and Motorola data bus selection and a "PowerSave" mode to further reduce sleep current to a minimum during sleep mode. It supports the Exar's enhanced features of programmable FIFO trigger level and FIFO level counters, automatic hardware (RTS/CTS) and software flow control, automatic RS-485 half duplex direction control output and a complete modem interface. An internal loopback capability allows system diagnostics. Independent programmable fractional baud rate generators are provided in each channel to select data rates up to 8 Mbps at 3.3 Volt and 8X sampling clock. The M2751 is available in a 48-pin TQFP package.