FAST CMOS OCTAL
BIDIRECTIONAL
TRANSCEIVERS
Integrated Device Technology, Inc.
IDT54/74FCT245T/AT/CT/DT - 2245T/AT/CT
IDT54/74FCT640T/AT/CT
IDT54/74FCT645T/AT/CT/DT
FEATURES:
• Common features:
– Low input and output leakage
≤1µA
(max.)
– CMOS power levels
– True TTL input and output compatibility
– V
OH
= 3.3V (typ.)
– V
OL
= 0.3V (typ.)
– Meets or exceeds JEDEC standard 18 specifications
– Product available in Radiation Tolerant and Radiation
Enhanced versions
– Military product compliant to MIL-STD-883, Class B
and DESC listed (dual marked)
– Available in DIP, SOIC, SSOP, QSOP, CERPACK
and LCC packages
• Features for FCT245T/FCT640T/FCT645T:
– Std., A, C and D speed grades
– High drive outputs (-15mA I
OH
, 64mA I
OL
)
• Features for FCT2245T:
– Std., A and C speed grades
– Resistor outputs (-15mA I
OH
, 12mA I
OL
Com.)
(-12mA I
OH
, 12mA I
OL
Mil.)
– Reduced system switching noise
DESCRIPTION:
The IDT octal bidirectional transceivers are built using an
advanced dual metal CMOS technology. The FCT245T/
FCT2245T, FCT640T and FCT645T are designed for asyn-
chronous two-way communication between data buses. The
transmit/receive (T/
R
) input determines 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 FCT245T/FCT2245T and FCT645T transceivers have
non-inverting outputs. The FCT640T has inverting outputs.
The FCT2245T has balanced drive outputs with current
limiting resistors. This offers low ground bounce, minimal
undershoot and controlled output fall times- reducing the need
for external series terminating resistors. The FCT2xxxT parts
are plug-in replacements for FCTxxxT parts.
FUNCTIONAL BLOCK DIAGRAM
T/R
OE
A
0
B
0
A
1
B
1
A
2
B
2
A
3
B
3
A
4
B
4
A
5
B
5
A
6
B
6
A
7
B
7
FCT245T/2245T, FCT645T are non-inverting options.
FCT640T is the inverting options.
2539 drw 01
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
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
P20-1
D20-1
SO20-2
SO20-7*
SO20-8**
&
E20-1
18
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
2539 drw 02
DIP/SOIC/SSOP/QSOP/CERPACK
TOP VIEW
*FCT245T/2245T, FCT645T only.
**FCT245T/2245T, FCT640T
INDEX
A
2
A
3
A
4
A
5
A
6
A
1
A
0
T/R
Vcc
OE
3
4
5
6
7
8
2
20 19
18
1
17
16
15
14
9 10 11 12 13
L20-2
B
0
B
1
B
2
B
3
B
4
A
7
GND
B
7
B
6
B
5
2539 drw 03
LCC
TOP VIEW
MILITARY AND COMMERCIAL TEMPERATURE RANGES
©1995
Integrated Device Technology, Inc.
AUGUST 1995
DSC-4611/4
6.9
1
IDT [ INTEGRATED DEVICE TECHNOLOGY ]
