XR21B1421 Enhanced 1-Ch Full-Speed USB HID to UART Bridge FEATURES General Description 15kV ESD on USBD+/USBD- The XR21B1421 is an enhanced Universal Asynchronous Receiver and USB 2.0 Compliant, Full-Speed (12Mbps) Transmitter (UART) bridge to HID class USB interface. The USB interface Unique pre-programmed USB serial number is fully compliant to the USB 2.0 (Full-Speed) specification with 12 Mbps Internally generated 48MHz core clock USB 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 up to 12 Mbps other settings may be programmed in the on-chip OTP memory via the Fractional Baud Rate Generator USB interface using either HID reports or MaxLinear-supplied OTP pro- 512-byte TX and 512-byte RX FIFOs gramming tools. Auto Hardware / Software Flow Control Multidrop and Half-Duplex Modes The XR21B1421 includes an internal oscillator and does not require an Auto RS-485 Half-Duplex Control external crystal/oscillator. Any UART baud rate up to 12 Mbps may be generated with this internal clock and the fractional baud rate generator. Selectable GPIO or Modem I/O Up to 10 GPIOs 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. 24-pin or 28-pin QFN package Large 512-byte TX and RX FIFOs prevent buffer overflow errors and opti- Industrial -40C to +85C Temperature Range mize data throughput. Automatic half-duplex direction control and optional multi drop (9-bit) mode simplify both hardware and software in half-duplex APPLICATIONS RS-485 applications. Portable Medical Diagnostics The XR21B1421 uses the native OS HID driver using HID reports. The Blood Glucose Meters HID reports perform a variety of functions, including device configuration, Health and Fitness Wellness Monitors transmitting and receiving UART data, and programming of the on-chip Uninterruptible Power Supplies OTP. MaxLinear provides a .dll as an easy to use programming interface Energy Management Consoles to the HID reports. The XR21B1421 operates from a single 5V or 3.3V power supply and is Ordering Information page 53 available in a 24 or 28 pin QFN package. When powered with 5V input, the XR21B1421 supplies a regulated 3.3V output. The 24 pin package has a separate V supply voltage input for the Modem / GPIO pins. The IO 28 pin package has V internally tied to 3.3V. IO Block Diagram InInteterrnnalal TXTX FFrraacctitiononalal 5512-12-bybytete OOsscciillllatatoror BRBRGG TTXX F FIFIFOO (4(488MMHHzz)) RXRX 5512-12-bybytete RRXX F FIFIFOO USUSBB USUSBB SSllavavee In Inteterrffacacee InInteterrnnaall SSttatatusus andand CoConnttrrooll GPGPIIOOs/s/ ReReggiisstteerrss ModModeem m IIOO USUSBB OTOTPP DDeessccrriiptptororss UAUARRTT LDLDOO 3V3V33 1 / 54 exar.com/XR21B1421 Rev 1DXR21B1421 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 13 19 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 XR21B1421. 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 / 54 exar.com/XR21B1421 Rev 1D