Exar – XR21B1421 and XR21B1424: Rugged, High Throughput USB to Serial Bridge Devices

XR21B1421/424: Rugged, High Throughput USB to Serial Bridge Devices

The XR21B142x devices are fully compliant to the USB 2.0 (Full-Speed) specification with 12Mbps USB data transfer rate, and deliver significantly higher data throughput compared to competing devices, especially when multiple channels are operating simultaneously. Large 512-byte transmit (TX) and receive (RX) FIFOs enable a maximum data throughput of 9Mbps across up to four UART channels. The XR21B1424 provides 4 UART channels and the XR21B1421 provides a single channel UART and uses the native operating system HID (Human Interface Device) driver.


  • ±15kV ESD on USBD+/USBD-
  • Internally generated 48MHz core clock
  • Up to 10 GPIOs per channel
  • Suspend state GPIO configuration
  • Configurable clock output
  • Unique pre-programmed USB serial number
  • Up to 12Mbps baud rates
  • 5V tolerant GPIO inputs
  • 24- or 28-pin QFN and 64-pin LQFP packages
  • 1k MSRP: starts at $3.73 US