XR21B1420IL28TR-F

XR21B1420 Enhanced 1-Ch Full-Speed USB UART General Description FEATURES The XR21B1420 is an enhanced Universal Asynchronous Receiver and Transmitter (UART) bridge to USB interface. The USB interface is fully compliant to the USB 2.0 (Full-Speed) specification with 12 Mbps USB data transfer rate. The USB interface also supports USB suspend, resume and remote wakeup operations. The USB Vendor ID, Product ID, power mode, remote wakeup support, maximum power, and numerous other settings may be programmed in the on-chip OTP memory via the USB interface.  ±15kV ESD on USBD+/USBDUSB 2.0 Compliant, Full-Speed (12Mbps)  Unique pre-programmed USB serial number  Internally generated 48MHz core clock  Enhanced UART features  Baud rates from 300bps to 12 Mbps  Fractional Baud Rate Generator  512-byte TX and 512-byte RX FIFOs  Auto Hardware / Software Flow Control  Multidrop and Half-Duplex Modes  Auto RS-485 Half-Duplex Control  Selectable GPIO or Modem I/O  Up to 10 GPIOs  5V tolerant GPIO inputs  Suspend state GPIO configuration  Configurable clock output  28-pin QFN package  Industrial -40°C to +85°C Temperature Range  The XR21B1420 includes an internal oscillator and does not require an external crystal/oscillator. Any UART baud rate from 300 bps to 12 Mbps may be generated with this internal clock and the fractional baud rate generator. The UART pins may also be configured as GPIO; direction, state, output driver type and input pull-up or pull-down resistors are programmed either through on chip OTP, or on the fly via memory mapped registers. Large 512-byte TX and RX FIFOs prevent buffer overflow errors and optimize data throughput. Automatic half-duplex direction control and optional multi drop (9-bit) mode simplify both hardware and software in half-duplex RS-485 applications. Wide mode allows for each individual received character to be monitored for errors. APPLICATIONS Building Automation Security Systems  Factory and Process Control  ATM Terminals  The XR21B1420 uses the native OS CDC-ACM driver or a MaxLinear supplied custom driver. MaxLinear provides WHQL-certified software drivers for Windows 2000, XP, Vista, 7, 8, 8.1, 10, and 11 as well as custom software drivers for Linux. Full source code is available.   The XR21B1420 operates from a single 5V or 3.3V power supply. When powered with 5V input, a regulated 3.3V output is supplied. USB to Serial Controllers Ordering Information - page 62 Block Diagram Throughput Comparison Internal Oscillator (48MHz) USB Fractional BRG USB Slave Interface USB Descriptors Internal Status and Control Registers 512-byte TX FIFO TX 1840k 512-byte RX FIFO RX 1610k 1380k Competitor MaxLinear 1150k 920k GPIOs/ Modem IO OTP 690k 460k 230k UART LDO 3V3 • www.maxlinear.com • 271DSR00 0k 230k 460k 920k Data Rate (bps) 1840k XR21B1420 Absolute Maximum Ratings Operating Conditions Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Maximum Rating may affect device reliability and lifetime. Operating Temperature Range................................-40°C to +85°C 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............................................................125°C Electrical Characteristics Unless otherwise noted: TA = -40°C to +85°C, VCC_REG = +4.4V to +5.25V or +3.0V to +3.6V. Symbol Parameter Conditions Min Typ Max Units 15 23 mA 0.85 1.35 mA 3.3 3.6 V Power ICC Power Supply Current ISUSP Suspend Mode Current VOUT Regulated Output Voltage (VCC pin) VCC_REG = +4.4V to +5.25V (Does not include current that VOUT sources to external devices or to VIO) VCC_REG = +4.4V to +5.25V. Maximum output current = 200 mA including the supply current of the XR21B1420. 3 UART, USB_STAT and GPIO Pins VIL Input Low Voltage -0.3 0.25* VCC V VIH Input High Voltage 0.70* VCC 5.5 V VOL Output Low Voltage IOL = 1mA, VCC = +3.6V 0.5 V VOH Output High Voltage IOH = -1.5mA, VCC = +3.6V VCC V IIL Input Low Leakage Current VCC = +3V to +3.6V, VCC_REG = +4.4V to +5.25V, VINPUT = 0V ±10 µA IIH Input High Leakage Current VCC = +3V to +3.6V, VCC_REG = +4.4V to +5.25V, VINPUT = +3.3V ±10 µA VCC = +3V to +3.6V, VCC_REG = +4.4V to +5.25V, VINPUT = +5.5V ±120 µA 5 pF CIN 271DSR00 Input Pin Capacitance 2 2.8 Rev. 2D XR21B1420 Symbol Parameter Conditions Min Typ Max Units USB I/O Pins VIL Input Low Voltage -0.3 0.8 V VIH Input High Voltage 2.0 5.5 V VOL Output Low Voltage External 15kΩ to GND on USBD+ and USBD- pins 0 0.3 V VOH Output High Voltage External 15kΩ to GND on USBD+ and USBD- pins 2.8 3.6 V VDrvZ Driver Output Impedance 28 44 Ω GPIO2/DSR# TX RX GPIO5/RTS#/RS485 GPIO4/CTS# NC 26 25 24 23 22 2 27 1 28 GPIO1/CD# GPIO0/RI#/RWK# GPIO3/DTR# Pin Configuration MaxLinear XR21B1420 21 NC 20 NC GND 3 19 GPIO6/CLK USBD+ 4 18 NC USBD- 5 17 GPIO7/RS485 VCC 6 16 GPIO8/TXT 15 NC 14 USB_STAT2 USB_STAT1 NC NC GPIO9/RXT 13 10 12 9 11 8 RESET# 7 VBUS_SENSE VCC_REG E_PAD Top View 271DSR00 3 Rev. 2D XR21B1420 Pin Assignments Pin No. Pin Name Type Description 1 GPIO1/CD# I/O General purpose I/O, or UART Carrier-Detect input (active low). Defaults to GPIO input with internal pull-up resistor. 2 GPIO0/RI#/RWK# I/O General purpose I/O, or UART Ring-Indicator input (active low), or Remote Wakeup input. Defaults to GPIO input with internal pull-up resistor. Wakeup signaling to the USB host is sent when a falling edge is detected. See “Remote Wakeup” on page 7. 3 GND 4 USBD+ I/O USB port differential data positive. This pin has internal pull-up resistor compliant to the USB 2.0 specification. The ESD protection on this pin is ±15kV HBM. 5 USBD- I/O USB port differential data negative. The ESD protection on this pin is ±15kV HBM. 6 VCC PWR 3.3V power to the device, or 3.3V power output from the device when 5V power is supplied to VCC_REG pin. 3.3V output power can source up to 200 mA maximum (including the device) and should be decoupled by minimum of 4.7µF ceramic capacitor. See “USB Power Modes” on page 9. 7 VCC_REG PWR 5V or 3.3V power to the device. In bus-powered mode, connect VBUS (5V) power from the USB host to this pin and to the VBUS_SENSE pin. See Figure 1. To conform to USB specifications, an inrush current limiting circuit is recommended. In self-powered mode, connect onboard 5V or 3.3V source to this pin and VBUS from the USB host to the VBUS_SENSE pin. See Figure 2 and Figure 3. USB specification requires a minimum of 1uF and a maximum of 10uF of decoupling on VBUS power. 8 VBUS_SENSE I Must be connected to VBUS power from the USB host PC. This pin is used to disable the internal pull-up resistor on the USBD+ signal when VBUS is not present. In bus-powered mode, connect VBUS (5V) power from the USB host to this pin and to the VCC_REG pin - see Figure 1. In self-powered mode, connect VBUS from the USB host to this pin. This pin must be decoupled by a 4.7uF tantalum capacitor. 9 RESET# I/O OD Active low open drain output. Asserted at power on or any time device is reset by either register or USB bus reset. As an input, must be asserted for at least 15µs to force a device reset. Reset pulse width input of shorter than 15µs will have unknown effects. A weak internal pull-up resistor provides noise immunity if left unconnected. 10 GPIO9/RXT I/O General purpose I/O, or UART receive data indicator. Defaults to GPIO input with internal pullup resistor. See “TXT and RXT Pins” on page 16. When configured as receive indicator, this pin will toggle at ~10Hz intervals while the UART is receiving data. 11 USB_STAT2 O / OD This pin has the same functionality as the USB_STAT1 pin. However, the default output for this pin is active low polarity, asserted whenever the XR21B1420 is placed into a suspended state. This default may be changed via the PIN_CFG_USB_STAT2 register. 12 USB_STAT1 O The USB_STAT1 output pin may be used to indicate any of three USB status conditions: 1. USB_STAT1 is asserted when the USB host asserts USB reset. 2. USB_STAT1 is asserted when the USB host PC places the XR21B1420 device into the suspend state. 3. USB_STAT1 is asserted when it is not safe to draw the amount of current requested in the Device Maximum Power field of the Configuration Descriptor. a. For a low power device (