Document
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FAST CMOS OCTAL BIDIRECTIONAL TRANSCEIVERS
DESCRIPTION:
IDT54/74FCT245/A/C IDT54/74FCT640/A/C IDT54/74FCT645/A/C
Integrated Device Technology, Inc.
FEATURES:
• IDT54/74FCT245/640/645 equivalent to FAST™ speed and drive • IDT54/74FCT245A/640A/645A 25% faster than FAST • IDT54/74FCT245C/640C/645C 40% faster than FAST • TTL input and output level compatible • CMOS output level compatible • IOL = 64mA (commercial) and 48mA (military) • Input current levels only 5µA max. • CMOS power levels (2.5mW typical static) • Direction control and over-riding 3-state control • Product available in Radiation Tolerant and Radiation Enhanced versions • Military product compliant to MIL-STD-883, Class B and DESC listed • 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 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 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 A0 B0 A1 B1 A2 B2 A3 B3
PIN CONFIGURATIONS
T/R A0 A1 A2 A3 A4 A5 A6 A7 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 B0 B1 B2 B3 B4 B5 B6 B7
DIP/SOIC/CERPACK TOP VIEW
INDEX
B4 A5 B5 A6 B6 A7 B7
NOTES: 1. FCT245, 645 are noninverting options. 2. FCT640 is the inverting option.
2534 drw 02
A2 A3 A4 A5 A6
A1 A0 T/R Vcc OE
3 2 4 5 6 7 8 1 20 19 18 17 16 15 14 9 10 11 12 13
A4
L20-2
B0 B1 B2 B3 B4
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
©1992 Integrated Device Technology, Inc.
A7 GND B7 B6 B5
LCC TOP VIEW
2534 drw 01
MAY 1992
DSC-4201/3
7.9
1
IDT54/74FCT245/A/C, IDT54/74FCT640/A/C, IDT54/74FCT645/A/C FAST CMOS OCTAL BIDIRECTIONAL TRANSCEIVERS
MILITARY AND COMMERCIAL TEMPERATURE RANGES
PIN DESCRIPTION
Pin Names Description Output Enable Input (Active LOW) Transmit/Receive Input Side A Inputs or 3-State Outputs Side B Inputs or 3-State Outputs
2534 tbl 05
FUNCTION TABLE(2)
Inputs
OE T/R
A0–A7 B0–B7
OE
L L H
T/R L H X
Outputs Bus B Data to Bus A(1) Bus A Data to Bus B(1) High Z State
2534 tbl 06
NOTES: 1. 640 is inverting from input to output. 2. H = HIGH Voltage Level L = LOW Voltage Level X = Don’t Care
ABSOLUTE MAXIMUM RATINGS(1)
Symbol Rating VTERM(2) Terminal Voltage with Respect to GND VTERM(3) Terminal Voltage with Respect to GND TA Operating Temperature TBIAS Temperat.