XR16L2450 Datasheet, PDF (1/30 Pages) Exar Corporation – 2.25V TO 5.5V DUART

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OCTOBER 2004
GENERAL DESCRIPTION
The XR16L2450 (L2450) is a dual universal asyn-
chronous receiver and transmitter (UART). The
XR16L2450 is an improved version of the
ST16C2450 with lower operating voltage and 5 volt
tolerant inputs. The L2450 provides enhanced UART
functions, a modem control interface and data rates
up to 1.5 Mbps. Onboard status registers provide the
user with error indications and operational status. In-
dependent programmable baud rate generators are
provided to select transmit and receive clock rates up
to 1.5 Mbps. An internal loopback capability allows
onboard diagnostics. The L2450 is available in a 44-
pin PLCC and 48-pin TQFP packages. The L2450 is
fabricated in an advanced CMOS process capable of
operating from 2.25 volt to 5.5 volt power supply with
5 volt tolerant inputs.
APPLICATIONS
• Portable Appliances
• Telecommunication Network Routers
• Ethernet Network Routers
• Cellular Data Devices
• Factory Automation and Process Controls
XR16L2450
2.25V TO 5.5V DUART
FEATURES
REV. 1.1.0
• 2.25 to 5.5 Volt Operation
• 5 Volt Tolerant Inputs
• Pin-to-pin compatible to Exar’s ST16C2450,
ST16C2550, XR16L2550, XR16L2750 and
XR16C2850
• Pin-to-pin compatible to TI’s TL16C752B on the 48-
TQFP package
• 2 independent UART channels
■ Up to 1.5 Mbps data rate with a 24 MHz crystal
oscillator or external clock frequency
■ 1 byte Transmit FIFO
■ 1 byte Receive FIFO with error tags
■ Status report registers
■ Modem control signals (CTS#, RTS#, DSR#,
DTR#, RI#, CD#)
■ Programmable character lengths (5, 6, 7, 8)
with even, odd, or no parity
• Crystal oscillator or external clock input
• TTL compatible inputs, outputs
• Industrial temperature ranges
• 48-TQFP and 44-PLCC packages
FIGURE 1. XR16L2450 BLOCK DIAGRAM
A2:A0
D7:D0
IOR#
IOW#
CSA#
CSB#
INTA
INTB
Reset
8-bit Data
Bus
Interface
*5V Tolerant inputs
UART Channel A
UART
Regs
THR
RHR
BRG
Modem I/Os
UART Channel B
(same as Channel A)
Crystal Osc/Buffer
2.25 to 5.5 Volt VCC
TXA
RXA
RTSA#, CTSA#,
DTRA#, DSRA#,
CDA#, RIA#, OP2A#
TXB
RXB
RTSB#, CTSB#,
DTRB#, DSRB#,
CDB#, RIB#, OP2B#
XTAL1
XTAL2
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • [phone] • FAX [phone] • www.exar.com