EXAR Corporation, 48720 Kato Road, Fremont, CA 94538 • (510) 668-7000 • FAX (510) 668-7017
ST16C450
Rev. 4.20
PLCC Package
UNIVERSAL ASYNCHRONOUS
RECEIVER/TRANSMITTER (UART)
GENERAL DESCRIPTION
The ST16C450 is a universal asynchronous receiver
and transmitter. The ST16C450 is an improved ver-
sion of the NS16450 UART with higher operating
speed and lower access time. A programmable baud
rate generator is provided to select transmit and
receive clock rates from 50 Bps to 1.5 Mbps.
The ST16C450 on board status registers provides the
error conditions, type and status of the transfer
operation being performed. Included is complete
MODEM control capability, and a processor interrupt
system that may be software tailored to the user’s
requirements. The ST16C450 provides internal loop-
back capability for on board diagnostic testing.
The ST16C450 is available in 40 pin PDIP, 44 pin
PLCC, and 48 pin TQFP packages. It is fabricated in
an advanced CMOS process to achieve low drain
power and high speed requirements.
FEATURES
• Pin to pin and functionally compatible to the Indus-
try Standard 16450
• 2.97 to 5.5 volt operation
• 1.5 Mbps transmit/receive operation (24MHz)
• Programmable word lengths (5, 6, 7, 8)
• Even, odd, force, or no parity generation and
detection
• Independent transmit and receive control
• Standard modem interface
• Low operating current ( 1.2mA typ.)
ORDERING INFORMATION
6
5
4
3
2
1
44
43
42
41
40
7
8
9
10
11
12
13
14
15
16
17
39
38
37
36
35
34
33
32
31
30
29
18
19
20
21
22
23
24
25
26
27
28
D5
D6
D7
RCLK
RX
N.C.
TX
CS0
CS1
-CS2
-BAUDOUT
RESET
-OP1
-DTR
-RTS
-OP2
N.C.
INT
N.C.
A0
A1
A2
D4
D3
D2
D1
D0
N.C.
VCC
-RI
-CD
-DSR
-CTS
XTAL1
XTAL2
-IOW
IOW
GND
N.C.
-IOR
IOR
-DDIS
CSOUT
-AS
ST16C450CJ44
Part number Package Operating temperature Device Status
ST16C450CP40 40-Lead PDIP 0° C to + 70° C Active. See the ST16C450CQ48 for new designs.
ST16C450CJ44 44-Lead PLCC 0° C to + 70° C Active
ST16C450CQ48 48-Lead TQFP 0° C to + 70° C Active
ST16C450IP40 40-Lead PDIP -40° C to + 85° C Active. See the ST16C450IQ48 for new designs.
ST16C450IJ44 44-Lead PLCC -40° C to + 85° C Active
ST16C450IQ48 48-Lead TQFP -40° C to + 85° C Active
September 2003
