XR21B1422 Enhanced 2-Ch Full-Speed USB UART FEATURES General Description 15kV ESD on USBD+/USBD- The XR21B1422 is an enhanced Universal Asynchronous Receiver and USB 2.0 Compliant, Full-Speed (12Mbps) Transmitter (UART) bridge to USB interface. The USB interface is fully Unique pre-programmed USB serial number compliant to the USB 2.0 (Full-Speed) specification with 12 Mbps USB Internally generated 48MHz core clock data transfer rate. The USB interface also supports USB suspend, Enhanced UART features resume and remote wakeup operations. The USB Vendor ID, Product ID, power mode, remote wakeup support, maximum power, and numerous Baud rates from 300 bps to 12 Mbps other settings may be programmed in the on-chip OTP memory via the Fractional Baud Rate Generator USB interface. 512-byte TX and 512-byte RX FIFOs Auto Hardware / Software Flow Control The XR21B1422 includes an internal oscillator and does not require an Multidrop and Half-Duplex Modes external crystal/oscillator. Any UART baud rate from 300 bps to 12 Mbps Auto RS-485 Half-Duplex Control may be generated with this internal clock and the fractional baud rate generator. Selectable GPIO or Modem I/O Up to 10 GPIOs per channel The UART pins for each port may also be configured as GPIO direction, 5V tolerant GPIO inputs state, output driver type and input pull-up or pull-down resistors are pro- Suspend state GPIO configuration grammed either through on chip OTP, or on the fly via memory mapped Configurable clock output registers. 40-pin QFN package Large 512-byte TX and RX FIFOs prevent buffer overflow errors and opti- Industrial -40C to +85C Temperature mize data throughput. Automatic half-duplex direction control and optional Range multi drop (9-bit) mode simplify both hardware and software in half-duplex RS-485 applications. Wide mode allows for each individual received APPLICATIONS character to be monitored for errors. Building Automation The XR21B1422 uses the native OS CDC-ACM driver or a MaxLinear Security Systems supplied custom driver. MaxLinear provides WHQL/HCK-certified soft- Factory and Process Control ware drivers for Windows XP, Vista, 7, 8, 8.1 and 10 as well as software ATM Terminals drivers for Windows CE, Linux and Mac OS X. Full source code is USB to Serial Controllers available. The XR21B1422 operates from a single 5V or 3.3V power supply. When Ordering Information - back page powered with 5V input, a regulated 3.3V output is supplied. Block Diagram VIO Internal TX Fractional 512-byte Oscillator Throughput Comparison BRG TX FIFO (48MHz) 1840k RX 512-byte 1610k Competitor RX FIFO MaxLinear 1380k USB USB Slave Interface Internal 1150k Status and 920k Control GPIOs/ Registers 690k Modem IO USB OTP Descriptors 460k 230k 0k UART Ch A 230k 460k 920k 1840k Data Rate (bps) LDO 3V3 UART Ch B (same as Ch A) 1 / 63 exar.com/XR21B1422 Rev 1DXR21B1422 Absolute Maximum Ratings Operating Conditions Stresses beyond those listed under Absolute Maximum Operating Temperature Range.....................-40C to +85C Ratings may cause permanent damage to the device. Exposure to any Maximum Rating may affect device reliability and lifetime. Supply Voltage (VCC REG)......................................+5.75V Supply Voltage (VCC, VIO)............................................+4V Input Voltage (VBUS SENSE).......................-0.3 to +5.75V Input Voltage (All other pins)............................-0.3 to +5.6V Junction Temperature.................................................125C Electrical Characteristics Unless otherwise noted: T = -40C to +85C, VCC REG = +4.4V to +5.25V or +3.0V to +3.6V, VIO = +1.8V to +3.6V. A Symbol Parameter Conditions Min Typ Max Units Power I Power Supply Current VCC REG = +4.4V to +5.25V 15 23 mA CC I Lowpower Mode Current 0.85 1.25 mA SUSP V Regulated Output Voltage (VCC pin) VCC REG = +4.4V to +5.25V. 3 3.3 3.6 V OUT Maximum output current = 200 mA including the supply current of the XR21B1422. UART, USB STAT and GPIO Pins V Input Low Voltage -0.3 0.25* V IL VIO V Input High Voltage 0.70* 5.5 V IH VIO V Output Low Voltage IOL = 1mA, VIO = +1.6V 0.3 V OL IOL = 4mA, VIO = +3.6V 0.5 V V Output High Voltage IOH = -400uA, VIO = +1.6V 1.3 VIO V OH IOH = -1.5mA, VIO = +3.6V 2.8 VIO V I Input Low Leakage Current VIO = +3V to +3.6V, VCC REG = +4.4V to 10 A IL +5.25V, V = 0V INPUT I Input High Leakage Current VIO = +3V to +3.6V, VCC REG = +4.4V to 10 A IH +5.25V, V = +3.3V INPUT VIO = +3V to +3.6V, VCC REG = +4.4V to 120 A +5.25V, V = +5.5V INPUT C Input Pin Capacitance 5 pF IN 2 / 63 exar.com/XR21B1422 Rev 1D