Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510) 668-7000 • FAX (510) 668-7017 • www.exar.com
ST16C650A
2.90V TO 5.5V UART WITH 32-BYTE FIFO
JUNE 2010 REV. 5.0.3
GENERAL DESCRIPTION
The ST16C650A
1
(650A) is a 2.90 to 5.5 volt
Universal Asynchronous Receiver and Transmitter
(UART) with 5 volt tolerant inputs. This device
supports Intel and PC ISA mode data bus interfaces
and is software compatible to industry standard
16C450, 16C550, and ST16C580 UARTs.
The 650A has 32 bytes of TX and RX FIFOs and is
capable of operating up to serial data rates of 3.125
Mbps at 5 volt supply voltage. The internal registers
include the 16C550 register set plus Exar’s enhanced
registers for additional features to support today’s
highly demanding data communication needs. The
enhanced features include automatic hardware and
software flow control, selectable TX and RX trigger
levels, and wireless infrared (IrDA) encoder/decoder.
The device provides a new capability to give user the
ability to program the wireless infrared encoder
output pulse width, hence reducing the power
consumption of a handheld unit.
The ST16C650A device comes in the 44-pin PLCC
and 48-pin TQFP packages in both the commercial
and industrial temperature ranges.
NOTE: 1 Covered by US patents #5,649,122.
FEATURES
Added features in devices with a top mark date code
of "HC YYWW" and newer:
■ 2.90 to 5.5 Volt Operation
■ 5 Volt Tolerant Inputs
■ Automatic RS485 Half-Duplex Control Output
■ Programmable Infrared Encoder Pulse Width
■ Sleep Mode with Wake-up Indicator
■ Device ID & Revision
■ Up to 3.125 Mbps Data Rate at 5 Volts
Added feature in devices with a top mark date code of
"I2 YYWW" and newer:
■ 0 ns address hold time
• Intel or PC Mode 8-bit Bus Interface
• 32-byte Transmit and Receive FIFOs
• Automatic Hardware (RTS/CTS) Flow Control
• Hardware Flow Control Hysteresis
• Automatic Software (Xon/Xoff) Flow Control
APPLICATIONS
• Battery Operated Electronics
• Handheld Terminal
• Personal Digital Assistants
• Cellular Phones DataPort
• Wireless Infrared Data Communications Systems
FIGURE 1. BLOCK DIAGRAM
XTAL1/CLK
XTAL2
Crystal Osc/Buffer
DTR#, DSR#,
RTS#, CTS#,
CD#, RI#
Intel or
PC Data
Bus
Interface
32 Byte TX FIFO
Baud Rate Generator
Infrared Encoder and
Pulse Width Control
Transmitter
UART
Configuration
Regs
IOR
IOR#
32 Byte RX FIFO
Infrared
Decoder
Receiver with Auto
Software Flow Control
Modem Control Signals
TX
RX
CTS Flow
Control
RTS Flow
Control
BRG
Prescaler
CS1
CS0
DDIS#
INT
TXRDY#
RDRDY#
A2:A0
D7:D0
IOW
CS2#
SEL
S1
S2
S3
IRQA
IRQB
IRQC
IOW#
RESET
PC Mode:
COM 1 to 4
Decode Logic
FIGURE 2. INTEL AND PC MODE PIN OUT
44-PLCC PACKAGE
48-TQFP PACKAGE
48
47
46
45
44
43
42
41
40
39
38
37
1
2
3
4
5
6
7
8
9
10
11
12
36
35
34
33
32
31
30
29
28
27
26
25
13
14
15
16
17
18
19
20
21
22
23
24
N.C.
D5
D6
D7
S2
A4
RX
TX
A5
A6
A7
LPT1#
N.C.
XTAL1
XTAL2
IOW#
A8
GND
IOR#
A3
S1
LPT2#
IRQC
AEN#
SEL
RESET
OP1#
DTR#
RTS#
S3
IRQA
IRQB
A0
A1
A2
N.C.
N.C.
D4
D3
D2
D1
D0
VCC
RI#
CD#
DSR#
CTS#
A9
ST16C650ACQ48
PC Mode (SEL = GND)
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#
SEL
INT
RXRDY#
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#
TXRDY#
AS#
ST16C650ACJ44
Intel Bus Mode (SEL = VCC)
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
S2
RX
A4
TX
A5
A6
A7
LPT1#
RESET
OP1#
DTR#
RTS#
S3
SEL
IRQA
IRQB
A0
A1
A2
D4
D3
D2
D1
D0
A9
VCC
RI#
CD#
DSR#
CTS#
XTAL1
XTAL2
IOW#
A8
GND
S1
IOR#
A3
LPT2#
IRQC
AEN#
ST16C650ACJ44
PC Mode (SEL = GND)
48
47
46
45
44
43
42
41
40
39
38
37
1
2
3
4
5
6
7
8
9
10
11
12
36
35
34
33
32
31
30
29
28
27
26
25
13
14
15
16
17
18
19
20
21
22
23
24
N.C.
D5
D6
D7
RCLK
N.C.
RX
TX
CS0
CS1
-CS2
-BAUDOUT
N.C.
XTAL1
XTAL2
IOW#
IOW
GND
IOR#
IOR
N.C.
AS#
SEL
RESET
OP1#
DTR#
RTS#
OP2#
INT
RXRDY#
A0
A1
A2
N.C.
N.C.
D4
D3
D2
D1
D0
VCC
RI#
CD#
DSR#
CTS#
N.C.
ST16C650ACQ48
Intel Bus Mode (SEL = VCC)
DDIS#
TXRDY#
ORDERING INFORMATION
PART NUMBER PACKAGE
OPERATING
T
EMPERATURE
R
ANGE
DEVICE STATUS
ST16C650ACJ44 44-Lead PLCC 0°C to +70°C Active
ST16C650ACQ48 48-Lead TQFP 0°C to +70°C Active
ST16C650AIJ44 44-Lead PLCC -40°C to +85°C Active
ST16C650AIQ48 48-Lead TQFP -40°C to +85°C Active
ST16C650A
2
2.90V TO 5.5V UART WITH 32-BYTE FIFO REV. 5.0.3