The XR16L27521 (2752) is a low voltage dual universal asynchronous receiver and transmitter (UART) with 5 Volt tolerant inputs. The device operates from 2.25 to 5.5 Volt supply range and is pin-to-pin compatible to Exar's ST16C2552 and XR16C2852. The 2752 register set is compatible to the ST16C2552 and the XR16C2852 enhanced features. It supports the Exar's enhanced features of 64 bytes of TX and RX FIFOs, 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. Onboard registers provide the user with operational status and data error flags. An internal loopback capability allows system diagnostics. Independent programmable baud rate generators are provided in each channel to select data rates up to 6.25 Mbps at 5 Volt and 8X sampling. The 2752 is available in the 44-pin PLCC package.