XR21B1420 Enhanced 1-Ch Full-Speed USB UART FEATURES General Description 15kV ESD on USBD+/USBD- The XR21B1420 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, Baud rates from 300bps to 12 Mbps power mode, remote wakeup support, maximum power, and numerous 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 XR21B1420 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 gen- Selectable GPIO or Modem I/O erator. Up to 10 GPIOs The UART pins may also be configured as GPIO direction, state, output 5V tolerant GPIO inputs driver type and input pull-up or pull-down resistors are programmed either Suspend state GPIO configuration through on chip OTP, or on the fly via memory mapped registers. Configurable clock output Large 512-byte TX and RX FIFOs prevent buffer overflow errors and opti- 28-pin QFN package mize data throughput. Automatic half-duplex direction control and optional Industrial -40C to +85C Temperature Range multi drop (9-bit) mode simplify both hardware and software in half-duplex RS-485 applications. Wide mode allows for each individual received char- APPLICATIONS acter to be monitored for errors. Building Automation The XR21B1420 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 2000, XP, Vista, 7, 8, 8.1 and 10 as well as soft- ATM Terminals ware drivers for Windows CE, Linux and Mac OS X. Full source code is USB to Serial Controllers available. The XR21B1420 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 Throughput Comparison InInteterrnnaall TXTX FFrracacttiioonalnal 515122--bbyytte e 1840k OOsciscillllaattoorr BRBRGG TTXX F FIFIFOO (4(488MMHHzz)) Competitor 1610k RXRX 515122--bbyytte e MaxLinear RRXX F FIFIFOO 1380k USUSBB 1150k UUSSB B SlSlavavee IInntteerrffacacee InInteterrnnaall SSttaattusus aandnd 920k CContontrrolol GPGPIIOOss// RRegiegissttererss 690k MMooddeemm IO IO USUSBB OTOTPP DDeescrscriipptotorrss 460k 230k UAUARTRT 0k 230k 460k 920k 1840k LDLDOO 3V33V3 Data Rate (bps) 1 / 63 exar.com/XR21B1420 Rev 2CXR21B1420 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)...............................................................+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: TA = -40C to +85C, VCC REG = +4.4V to +5.25V or +3.0V to +3.6V. 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 1.35 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 XR21B1420. UART, USB STAT and GPIO Pins V Input Low Voltage -0.3 0.25* V IL VCC V Input High Voltage 0.70* 5.5 V IH VCC V Output Low Voltage IOL = 1mA, VCC = +3.6V 0.5 V OL V Output High Voltage IOH = -1.5mA, VCC = +3.6V 2.8 VCC V OH I Input Low Leakage Current VCC = +3V to +3.6V, VCC REG = +4.4V to 10 A IL +5.25V, V = 0V INPUT I Input High Leakage Current VCC = +3V to +3.6V, VCC REG = +4.4V to 10 A IH +5.25V, V = +3.3V INPUT VCC = +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/XR21B1420 Rev 2C