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Fast CMOS Octal
Bidirectional Transceivers
Product Features
聲 PI74FCT245/640/645T and PI74FCT2245/2640T/2645T are pin
compatible with bipolar FAST聶 Series at a higher speed and
lower power consumption
聲 25 Ohm series resistor on all outputs (FCT2XXX only)
聲 TTL input and output levels
聲 Low ground bounce outputs
聲 Extremely low static power
聲 Hysteresis on all inputs
聲 Industrial operating temperature range: 聳40擄C to +85擄C
聲 Packages available:
聳 20-pin 173 mil wide plastic TSSOP (L)
聳 20-pin 300 mil wide plastic DIP (P)
聳 20-pin 150 mil wide plastic QSOP (Q)
聳 20-pin 150 mil wide plastic TQSOP (R)
聳 20-pin 300 mil wide plastic SOIC (S)
聳 20-pin 209 mil wide plastic SSOP (H)
聲 Device models available on request
Product Description
Pericom Semiconductor聮s PI74FCT series of logic circuits are
produced using the Company聮s advanced 0.6/0.8 micron CMOS
technology, achieving industry leading speed grades. All
PI74FCT2XXX devices have a built-in 25 Ohm series resistor on all
outputs to reduce noise because of reflections, thus eliminating the
need for an external terminating resistor.
The PI74FCT245T/640T/645T and PI74FCT2245T/2640T/2645T are
8-bit wide octal buffer bidirectional transceivers designed for
asynchronous 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.
Product Pin Configuration
T/R
A
0
A
1
A
2
A
3
A
4
A
5
A
6
A
7
GND
1
20
2
19
3
18
4
20-Pin
17
5
L,P,Q
16
6
R,S,H
15
7
14
8
13
9
12
10
11
Logic Block Diagram
T/R
OE
A0
B0
A1
B1
A2
B2
A3
B3
A4
B4
A5
B5
A6
B6
A7
B7
Vcc
OE
B
0
B
1
B
2
B
3
B
4
B
5
B
6
B
7
Product Pin Description
Pin Name
OE
T/R
A
0
-A
7
B
0
-B
7
GND
V
CC
Description
3-State Output Enable Inputs (Active LOW)
Transmit/Receive Input
Side A Inputs or 3-State Outputs
Side B Inputs or 3-State Outputs
Ground
Power
Truth Table
(1)
Inputs
OE
T/R
L
L
L
H
H
X
1.
2.
1
Outputs
Bus B Data to Bus A
(2)
Bus A Data to Bus B
(2)
High Z State
FCT245, 2245, 645, 2645 are non-inverting options.
FCT640 & FCT2640 are inverting options.
H = High Voltage Level, X = Don't Care, L = Low
Voltage Level, Z = High Impedance
640 is inverting from input to output.
PS2012B
09/22/99
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