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Integrated Device Technology, Inc.
FAST CMOS OCTAL
BIDIRECTIONAL
TRANSCEIVERS
IDT54/74FCT245/A/C
IDT54/74FCT640/A/C
IDT54/74FCT645/A/C
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
DESCRIPTION:
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.
DESC listed
• Meets or exceeds JEDEC Standard 18 specifications
FUNCTIONAL BLOCK DIAGRAM PIN CONFIGURATIONS
T/R
A
A
A
OE
0
B
0
1
B
1
2
GND B7
T/R
A0
A1
A2
A3
A4
A5
A6
A7
1
2
3
4
5
6
7
8
9
10
P20-1
D20-1
SO20-2
E20-1
20
Vcc
19
OE
18
B0
17
16
15
&
14
13
12
11
B
B2
B3
B4
B5
B6
1
B
A
3
A
4
A
5
A
6
A
7
NOTES:
1. FCT245, 645 are noninverting options.
2. FCT640 is the inverting option.
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
FAST is a registered trademark of National Semiconductor Co.
2534 drw 02
2
B
3
B
4
B
5
B
6
B
7
DIP/SOIC/CERPACK
INDEX
4
A2
5
A3
6
A4
7
A5
8
A6
TOP VIEW
1
A0A
32
1
L20-2
10 11 12
9
7
A
GND
LCC
TOP VIEW
T/R
20
B7
Vcc
OE
19
18
17
16
15
14
13
5
B6B
2534 drw 01
B0
B1
B2
B3
B4
MILITARY AND COMMERCIAL TEMPERATURE RANGES MAY 1992
1992 Integrated Device Technology, Inc. 7.9 DSC-4201/3
1
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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
OE
T/
R
0–A7 Side A Inputs or 3-State Outputs
A
0–B7 Side B Inputs or 3-State Outputs
B
ABSOLUTE MAXIMUM RATINGS
Symbol Rating Commercial Military Unit
(2)
V
TERM
(3)
V
TERM
T
A Operating 0 to +70 –55 to +125 °C
T
BIAS Temperature –55 to +125 –65 to +135 °C
T
STG Storage –55 to +125 –65 to +150 °C
P
T Power Dissipation 0.5 0.5 W
OUT DC Output Current 120 120 mA
I
NOTES: 2534 tbl 01
1. Stresses greater than those listed under ABSOLUTE MAXIMUM
RATINGS may cause permanent damage to the device. This is a stress
rating only and functional operation of the device at these or any other
conditions above those indicated in the operational sections of this
specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect reliability. No terminal voltage
may exceed V
2. Inputs and V
3. Outputs and I/O terminals.
Output Enable Input (Active LOW)
Transmit/Receive Input
2534 tbl 05
(1)
Terminal Voltage –0.5 to +7.0 –0.5 to +7.0 V
with Respect
to GND
Terminal Voltage –0.5 to VCC –0.5 to VCC V
with Respect
to GND
Temperature
Under Bias
Temperature
CC by +0.5V unless otherwise noted.
CC terminals.
FUNCTION TABLE
(2)
Inputs
OE
OE
L L Bus B Data to Bus A
L H Bus A Data to Bus B
T/
R
R
Outputs
(1)
(1)
H X High Z State
NOTES: 2534 tbl 06
1. 640 is inverting from input to output.
2. H = HIGH Voltage Level
L = LOW Voltage Level
X = Don’t Care
CAPACITANCE (TA = +25°C, f = 1.0MHz)
Symbol Parameter
IN Input Capacitance VIN = 0V 6 10 pF
C
I/O I/O Capacitance VOUT = 0V 8 12 pF
C
NOTE: 2534 tbl 02
1. This parameter is measured at characterization but not tested.
(1)
Conditions Typ. Max. Unit
7.9 2
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IDT54/74FCT245/A/C, IDT54/74FCT640/A/C, IDT54/74FCT645/A/C
FAST CMOS OCTAL BIDIRECTIONAL TRANSCEIVERS MILITARY AND COMMERCIAL TEMPERATURE RANGES
DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE
Following Conditions Apply Unless Otherwise Specified: VLC = 0.2V; VHC = VCC – 0.2V
Commercial: TA = 0°C to +70°C, VCC = 5.0V ± 5%; Military: TA = –55°C to +125°C, VCC = 5.0V ± 10%
Symbol Parameter Test Conditions
IH Input HIGH Level Guaranteed Logic HIGH Level 2.0 — — V
V
IL Input LOW Level Guaranteed Logic LOW Level — — 0.8 V
V
I
IH Input HIGH Current VCC = Max VI = VCC ——5µA
(Except I/O pins) V
(1)
I = 2.7V — — 5
Min. Typ.
IIL Input LOW Current VI = 0.5V — — –5
(Except I/O pins) VI = GND — — –5
IH Input HIGH Current VCC = Max VI = VCC ——15µA
I
(I/O pins only) V
I = 2.7V — — 15
IIL Input LOW Current VI = 0.5V — — –15
(I/O pins only) VI = GND — — –15
V
IK Clamp Diode Voltage VCC = Min., IN = –18mA — –0.7 –1.2 V
OS Short Circuit Current VCC = Max.
I
OH Output HIGH Voltage VCC = 3V, VIN = VLC or VHC, IOH = –32µAVHC VCC —V
V
V
CC = Min. IOH = –300µAVHC VCC —
IN = VIH or VIL IOH = –12mA MIL. 2.4 4.3 —
V
V
OL Output LOW Voltage VCC = 3V, VIN = VLC or VHC, IOL = 300µA — GND VLC V
(Port A and Port B) V
CC = Min. IOL = 300µA — GND VLC
(3)
, VO = GND –60 –120 — mA
OH = –15mA COM’L. 2.4 4.3 —
I
VIN = VIH or VIL IOL = 48mA MIL. — 0.3 0.55
OL = 64mA COM’L. — 0.3 0.55
I
NOTES: 2534 tbl 03
1. For conditions shown as Max. or Min., use appropriate value specified under Electrical Characteristics for the applicable device type.
2. Typical values are at V
3. Not more than one output should be shorted at one time. Duration of the short circuit test should not exceed one second.
4. This parameter is guaranteed but not tested.
CC = 5.0V, +25°C ambient and maximum loading.
(2)
Max. Unit
(4)
(4)
(4)
(4)
(4)
7.9 3