XR16L2750_05 Datasheet, PDF (1/48 Pages) Exar Corporation – 2.25V TO 5.5V DUART WITH 64-BYTE FIFO

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APRIL 2005
GENERAL DESCRIPTION
The XR16L2750¹ (2750) is a low voltage dual
universal asynchronous receiver and transmitter
(UART) with 5 Volt tolerant inputs. The device
operates from 2.25 to 5.5 Volt supply range and is
pin-to-pin compatible to Exar’s ST16C2550 and
XR16C2850 except the 48-TQFP package. The 2750
register set is compatible to the ST16C2550 and the
XR16C2850 enhanced features. It supports the
Exar’s enhanced features of 64 bytes of TX and RX
FIFOs, programmable FIFO trigger level and FIFO
level counters, automatic hardware (RTS/CTS) and
software flow control, automatic RS-485 half duplex
direction control output and a complete modem
interface. Onboard registers provide the user with
operational status and data error flags. An internal
loopback capability allows system diagnostics.
Independent programmable baud rate generators are
provided in each channel to select data rates up to
6.25 Mbps at 5 Volt and 8X sampling clock. The 2750
is available in 48-pin TQFP and 44-pin PLCC
packages.
NOTE: 1 Covered by U.S. Patent #5,649,122 and #5,949,787
APPLICATIONS
• Portable Appliances
• Telecommunication Network Routers
• Ethernet Network Routers
• Cellular Data Devices
• Factory Automation and Process Controls
XR16L2750
2.25V TO 5.5V DUART WITH 64-BYTE FIFO
FEATURES
REV. 1.2.1
• 2.25 to 5.5 Volt Operation
• 5 Volt Tolerant Inputs
• Pin-to-pin compatible to Exar’s ST16C2550 and
TI’s TL16C752B on the 48-TQFP package
• Pin alike XR16C2850 48-TQFP package but
without CLK8/16, CLKSEL and HDCNTL inputs
• Two independent UART channels
■ Reg set compatible to 16C2550 and 16C2850
■ Up to 6.25 Mbps at 5 Volt, 4 Mbps at 3.3 Volt,
and 3 Mbps at 2.5 Volt with 8X sampling rate
■ Transmit and Receive FIFOs of 64 bytes
■ Programmable TX and RX FIFO Trigger Levels
■ Transmit and Receive FIFO Level Counters
■ Automatic Hardware (RTS/CTS) Flow Control
■ Selectable Auto RTS Flow Control Hysteresis
■ Automatic Software (Xon/Xoff) Flow Control
■ Automatic RS-485 Half-duplex Direction
Control Output via RTS#
■ Wireless Infrared (IrDA 1.0) Encoder/Decoder
■ Automatic sleep mode
■ Full modem interface
• Device Identification and Revision
• Crystal oscillator or external clock input
• Industrial and commercial temperature ranges
• 48-TQFP and 44-PLCC packages
FIGURE 1. XR16L2750 BLOCK DIAGRAM
A2:A0
D7:D0
IOR#
IOW#
CSA#
CSB#
INTA
INTB
TXRDYA#
TXRDYB#
RXRDYA#
RXRDYB#
Reset
8-bit Data
Bus
Interface
* 5 Volt Tolerant Inputs
(Except XTAL1)
UART Channel A
UART
Regs
BRG
64 Byte TX FIFO
TX & RX
IR
ENDEC
64 Byte RX FIFO
UART Channel B
(same as Channel A)
Crystal Osc/Buffer
2.25 to 5.5 Volt VCC
GND
TXA, RXA, DTRA#,
DSRA#, RTSA#,
DTSA#, CDA#, RIA#,
OP2A#
TXB, RXB, DTRB#,
DSRB#, RTSB#,
CTSB#, CDB#, RIB#,
OP2B#
XTAL1
XTAL2
2750BLK
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • [phone] • FAX [phone] • www.exar.com