廬
FAST CMOS OCTAL
BIDIRECTIONAL
TRANSCEIVERS
DESCRIPTION:
IDT54/74FCT245/A/C
IDT54/74FCT640/A/C
IDT54/74FCT645/A/C
Integrated Device Technology, Inc.
FEATURES:
鈥?IDT54/74FCT245/640/645 equivalent to FAST鈩?speed
and drive
鈥?IDT54/74FCT245A/640A/645A 25% faster than FAST
鈥?IDT54/74FCT245C/640C/645C 40% faster than FAST
鈥?TTL input and output level compatible
鈥?CMOS output level compatible
鈥?I
OL
= 64mA (commercial) and 48mA (military)
鈥?Input current levels only 5碌A(chǔ) max.
鈥?CMOS power levels (2.5mW typical static)
鈥?Direction control and over-riding 3-state control
鈥?Product available in Radiation Tolerant and Radiation
Enhanced versions
鈥?Military product compliant to MIL-STD-883, Class B and
DESC listed
鈥?Meets or exceeds JEDEC Standard 18 specifications
The IDT octal bidirectional transceivers are built using an
advanced dual metal CMOS technology. The IDT54/
74FCT245/A/C, IDT54/74FCT640/A/C and IDT54/74FCT645/
A/C are designed for asynchronous two-way communication
between data buses. The transmit/receive (T/
R
) input deter-
mines the direction of data flow through the bidirectional
transceiver. Transmit (active HIGH) enables data from A
ports to B ports, and receive (active LOW) from B ports to A
ports. The output enable (
OE
) input, when HIGH, disables
both A and B ports by placing them in High-Z condition.
The IDT54/74FCT245/A/C and IDT54/74FCT645/A/C
transceivers have non-inverting outputs. The IDT54/
74FCT640/A/C has inverting outputs.
FUNCTIONAL BLOCK DIAGRAM
T/R
OE
A
0
B
0
A
1
B
1
A
2
B
2
A
3
B
3
PIN CONFIGURATIONS
T/R
A
0
A
1
A
2
A
3
A
4
A
5
A
6
A
7
GND
1
2
3
4
5
6
7
8
9
10
20
19
18
P20-1
D20-1
SO20-2
&
E20-1
17
16
15
14
13
12
11
Vcc
OE
B
0
B
1
B
2
B
3
B
4
B
5
B
6
B
7
DIP/SOIC/CERPACK
TOP VIEW
INDEX
B
4
A
5
B
5
A
6
B
6
A
7
B
7
NOTES:
1. FCT245, 645 are noninverting options.
2. FCT640 is the inverting option.
2534 drw 02
A
2
A
3
A
4
A
5
A
6
A
1
A
0
T/R
Vcc
OE
3 2
4
5
6
7
8
A
4
L20-2
20 19
18
1
17
16
15
14
9 10 11 12 13
B
0
B
1
B
2
B
3
B
4
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
FAST is a registered trademark of National Semiconductor Co.
MILITARY AND COMMERCIAL TEMPERATURE RANGES
漏1992
Integrated Device Technology, Inc.
A
7
GND
B
7
B
6
B
5
LCC
TOP VIEW
2534 drw 01
MAY 1992
DSC-4201/3
7.9
1
1
2
3
4
5
6
7
