Exar’s XR21B142x family of USB to serial bridge devices provide a straightforward interface with RS-232 or RS-485 serial networks through USB using a minimum of components and PCB space. The XR21B1420, XRB21B1422, and XRB21B1424 provide 1, 2, and 4 UART channels respectively. The XRB21B1421 provides a single channel UART and uses the native operating system HID driver. Fully compliant to USB 2.0 specifications with 12 Mbps USB data transfer rate, the new devices deliver increased data throughput, especially when multiple channels operate simultaneously. Large 512-byte transmit and receive FIFOs enable a maximum data throughput of 9 Mbps across up to four UART channels. With ±15 kV ESD protection on USB pins, the devices are ideally suited for rugged applications such as smart grid data collection, data aggregators and concentrators, security and access control systems, and ATM terminals. Powered directly from the USB host’s 5 V supply, the devices also feature an internal oscillator and an integrated LDO providing regulated 3.3 V power supply output. The XR21B1424 is available now in a 64 LQFP package. The XR21B1420/1 devices, packaged in a 24- or 28-pin QFN, are sampling in September. The XR21B1422, in a 40-pin QFN, begins sampling in October. Pricing starts at $3.73 each/1,000.