• Power off disable outputs permit “live insertion”
• 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, CERPACK and LCC packages
FUNCTIONAL BLOCK DIAGRAM
GBA
GAB
1
A
(1)
B
1
DESCRIPTION:
The IDT54/74FCT621T/AT is an octal transceiver with
non-inverting Open-Drain bus compatible outputs in both
send and receive directions. The B bus outputs are capable
of sinking 64mA providing very good capacitive drive
characteristics. These octal bus transceivers are designed for
asynchronous two-way communication between data buses.
The control function implementation allows for maximum
flexibility in timing.
PIN CONFIGURATIONS
GAB
A
A
A
A
A
A
A
A
GND
1
2
1
3
2
3
4
5
6
7
8
4
5
6
7
8
9
10
P20-1,
D20-1,
SO20-2
&
E20-1
DIP/SOIC/CERPACK
TOP VIEW
20
19
18
17
16
15
14
13
12
11
Vcc
GBA
B
1
B
2
B
3
B
4
B
5
B
6
B
7
B
8
2538 drw 02
2
32
4
5
6
7
8
10 11 12 13
9
8
A
A1A
GAB
1
L20-2
20 19
8
Vcc
GBA
18
17
16
15
14
B6B7B
B
1
B
2
B
3
B
4
B
5
2538 drw 03
A2–A
8
7 Other Transceivers
B
2–B8
2538 drw 01
INDEX
A
3
A
4
A
5
A
6
A
7
GND
LCC
TOP VIEW
The IDT logo is a registered trademark of Integreted Device Technology, Inc.
MILITARY AND COMMERCIAL TEMPERATURE RANGESAPRIL 1994
IDT54/74FCT621T/AT
FAST CMOS OCTAL BUS TRANSCEIVER (OPEN DRAIN)MILITARY AND COMMERCIAL TEMPERATURE RANGES
PIN DESCRIPTION
Pin NamesDescription
G
BA, GABEnable Inputs
1 – A8A Inputs or Open-drain Outputs
A
1 – B8B Inputs or Open-drain Outputs
B
2538 tbl 01
ABSOLUTE MAXIMUM RATINGS
SymbolRatingCommercialMilitaryUnit
(2)
VTERM
VTERM
TAOperating
TBIASTemperature
TSTGStorage
PTPower Dissipation0.50.5W
IOUTDC Output
NOTES:
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. Input and V
3. Outputs and I/O terminals only.
Terminal Voltage
–0.5 to +7.0–0.5 to +7.0V
with Respect to
GND
(3)
Terminal Voltage
with Respect to
GND
–0.5 to
V
0 to +70–55 to +125°C
Temperature
–55 to +125–65 to +135°C
Under Bias
–55 to +125–65 to +150°C
Temperature
–60 to +120 –60 to +120 mA
Current
CC by +0.5V unless otherwise noted.
CC terminals only.
CC +0.5
(1)
–0.5 to
VCC +0.5
V
2538 lnk 03
FUNCTION TABLE
(1)
Enable Inputs
GGBAGABFunction
LLB data to A bus
HHA data to B bus
HLOFF
LHB data to A bus
A data to B bus
NOTE:2538 tbl 02
1. H = HIGH Voltage Level.
L = LOW Voltage Level.
OFF = HIGH if pull-up resistor is connected to Open-Drain output.
CAPACITANCE (TA = +25°C, f = 1.0MHz)
SymbolParameter
CINInput
Capacitance
COUTOutput
Capacitance
NOTE:
1. This parameter is measured at characterization but not tested.
(1)
ConditionsTyp.Max. Unit
VIN = 0V610pF
VOUT = 0V812pF
2538 lnk 04
6.182
Page 3
IDT54/74FCT621T/AT
FAST CMOS OCTAL BUS TRANSCEIVER (OPEN DRAIN)MILITARY AND COMMERCIAL TEMPERATURE RANGES
DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE
Following conditions Apply Unless Otherwise Specified:
Commercial: TA = 0°C to +70°C, VCC = 5.0V ± 5%; Military: TA = –55°C to +125°C, VCC = 5.0V ± 10%
SymbolParameterTest Conditions
V
IHInput HIGH LevelGuaranteed Logic HIGH Level2.0——V
ILInput LOW LevelGuaranteed Logic LOW Level——0.8V
V
(5)
(5)
(5)
VCC = Max., VI = 2.7V——±1µA
VCC = Max., VI = 0.5V——±1µA
VCC = Max., VI = VCC (Max.)——±1µA