High Performance Low Voltage DUART with 32-Byte FIFO and PowerSave Feature

  • o1.62 to 3.63 Volt Operation
  • Pin-to-pin and software compatible to Exar's XR16L2551, XR16V2551 and XR16M2551
  • Two independent UART channels
    • Register set is 16550 compatible
    • Data rate of up to 16 Mbps at 3.3 V
    • Data rate of up to 12.5 Mbps at 2.5 V
    • Data rate of up to 8 Mbps at 1.8V
    • Fractional Baud Rate Generator
    • Transmit and Receive FIFOs of 32 bytes
    • Selectable TX and RX FIFO Trigger Levels
    • Automatic Hardware (RTS/CTS) Flow Control
    • Automatic Software (Xon/Xoff) Flow Control
    • Wireless Infrared (IrDA 1.0) Encoder/Decoder
    • Automatic sleep mode with wake-up interrupt
    • Full modem interface
  • PowerSave Feature reduces sleep current to 15 µA
  • Device Identification and Revision
  • Crystal oscillator (up to 24MHz) or external clock (up to 64MHz) input
  • 48-TQFP and 32-QFN packages
  • Pb-Free, RoHS Compliant Versions Offered

  • Portable Appliances
  • Telecommunication Network Routers
  • Ethernet Network Routers
  • Cellular Data Devices
  • Factory Automation and Process Controls

The XR16M26511 (M2651) is a high performance dual universal asynchronous receiver and transmitter (UART) with 32 byte TX and RX FIFOs. The device operates from 1.62 to 3.63 volts and is pin-to-pin and software compatible to the XR16V2551 and XR16L2551. The device includes 2 additional capabilities over the XR16M2650: Intel and Motorola data bus selection and a "PowerSave" mode to minimize the sleep current. It supports Exar's enhanced features of selectable FIFO trigger level, automatic hardware (RTS/CTS) and software flow control, and a complete modem interface. An internal loopback capability allows system diagnostics. Independent programmable fractional baud rate generators are provided in each channel to select data rates up to 16 Mbps at 3.3 Volt with 4X sampling clock. The M2651 is available in 48-pin TQFP and 32-pin QFN packages.

NOTE: 1Covered by U.S. Patent #5,649,122

For UART technical support or to obtain an IBIS model for this product, please email Exar's UART Technical Support group.

Part NumberPkg CodeRoHSMin
StatusBuy NowOrder Samples

Part Status Legend
Active - the part is released for sale, standard product.
EOL (End of Life) - the part is no longer being manufactured, there may or may not be inventory still in stock.
CF (Contact Factory) - the part is still active but customers should check with the factory for availability. Longer lead-times may apply.
PRE (Pre-introduction) - the part has not been introduced or the part number is an early version available for sample only.
OBS (Obsolete) - the part is no longer being manufactured and may not be ordered.
NRND (Not Recommended for New Designs) - the part is not recommended for new designs. 
CPU InterfaceIntel or Motorola
Max Data Rate @ 5/3.3/2.5/1.8V (Mbps)na/16/12.5/8
Tx/Rx FIFO (Bytes)32/32
Tx/Rx FIFO CtrsNo
Tx/Rx FIFO INT Trig4 Levels/ 4 Levels
IrDa SupYes
5V Tol InputsNo
Sup V1.62-3.63
PkgsTQFP-48, QFN-32
Data Rate @ 5/3.3/2.5Vna/16/12.5