– Low input and output leakage ≤1µA (max.)
– Extended commercial range of –40°C to +85°C
– CMOS power levels
– True TTL input and output compatibility
– V
OH = 3.3V (typ.)
– VOL = 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, TSSOP,
CERPACK and LCC packages
• Features for FCT646T/648T/652T:
– Std., A, C and D speed grades
– High drive outputs (-15mA IOH, 64mA IOL)
– Power off disable outputs permit “live insertion”
• Features for FCT2646T/2652T:
– Std., A, and C speed grades
– Resistor outputs(-15mA IOH, 12mA IOL Com.)
(-12mA IOH, 12mA IOL Mil.)
– Reduced system switching noise
IDT54/74FCT646T/AT/CT/DT - 2646T/AT/CT
IDT54/74FCT648T/AT/CT
IDT54/74FCT652T/AT/CT/DT - 2652T/AT/CT
DESCRIPTION:
The FCT646T/FCT2646T/FCT648T/FCT652T/2652T consist of a bus transceiver with 3-state D-type flip-flops and
control circuitry arranged for multiplexed transmission of data
directly from the data bus or from the internal storage registers.
The FCT652T/FCT2652T utilize GAB and
control the transceiver functions. The FCT646T/FCT2646T/
FCT648T utilize the enable control (G) and direction (DIR)
pins to control the transceiver functions.
SAB and SBA control pins are provided to select either realtime or stored data transfer. The circuitry used for select
control will eliminate the typical decoding glitch that occurs in
a multiplexer during the transition between stored and realtime data. A LOW input level selects real-time data and a
HIGH selects stored data.
Data on the A or B data bus, or both, can be stored in the
internal D flip-flops by LOW-to-HIGH transitions at the appropriate clock pins (CPAB or CPBA), regardless of the select or
enable control pins.
The FCT26xxT have 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. FCT2xxxT parts are
plug-in replacements for FCTxxxT parts.
GBA
signals to
FUNCTIONAL BLOCK DIAGRAM
IDT54/74FCT646/2646/648
646/2646/652/2652
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
DIR
CPBA
SBA
CPAB
SAB
ONLY
ONLY
G
A1
1 OF 8 CHANNELS
A REG
1D
C1
GBA
TO 7 OTHER CHANNELS
IDT54/74FCT652/2652
ONLY
GAB
B REG
C1
1D
646/2646/652/2652
ONLY
B1
2634 drw 01
MILITARY AND COMMERCIAL TEMPERATURE RANGESSEPTEMBER 1996
Real-Time B Data to A Bus
Stored B Data to A Bus
Real-Time A Data to B Bus
Stored A Data to B Bus
2634 tbl 02
FUNCTION TABLE (652)
InputsData I/OOperation or Function
GAB
NOTES: 2634 tbl 03
1. The data output functions may be enabled or disabled by various signals at the GAB or GBA inputs. Data
2. Select control = L: clocks can occur simultaneously.
3.A in B Register.
4.B in A Register.
GBA
CPABCPBASABSBAA1 - A8B1 - B8FCT652T/FCT2652T
GBA
L
HHH or L↑H or L↑X
L
X
H
L
L
L
L
H
H
H
H
XLH or L
L
L
H
HXH or L
↑
↑
↑
X
X
H or L↑X
X
↑
↑
X
H or LXX
X
X
X
(2)
X
XXX
L
H
X
X
X
X
(2)
L
H
X
X
InputInputIsolation
Store A and B Data
Input
Input
(1)
Store A, Hold B
Store A in Both Registers
Hold A, Store B
Store B in Both Registers
Input
Input
Unspecified
Output
Unspecified
Output
(1)
OutputInputReal-Time B Data to A Bus
Stored B Data to A Bus
InputOutputReal-Time A Data to B Bus
Stored A Data to B Bus
HLH or LH or LHHOutputOutputStored A Data to B Bus and Stored B Data to A Bus
input functions are always enabled, i.e. data at the bus pins will be stored on every LOW-to-HIGH transition
on the clock inputs.
Select control = H: clocks must be staggered in order to load both registers.
H = HIGH, L = LOW, X = Don't Care, ≠ = LOW-to-HIGH transition.
6.203
IDT54/74FCT646/2646/652/2652T/AT/CT/DT, 648T/AT/CT
FAST CMOS OCTAL TRANSCEIVER/REGISTERMILITARY AND COMMERCIAL TEMPERATURE RANGES
652/2652
646/2646/
648
BUS
A
BUS
B
GABGBACPABCPBASABSBA
LL XX XL
DIRGCPABCPBASABSBA
LL XX XL
REAL-TIME TRANSFER
BUS
A
BUS B TO A
BUS
B
2634 drw 06
652/2652
646/2646/
648
BUS
A
BUS
B
GABGBACPABCPBASABSBA
HH
X
XLX
DIRGCPABCPBASABSBA
HL XX L X
REAL-TIME TRANSFER
BUS
A
BUS A TO B
BUS
B
2634 drw 07
652/2652GABGBACPABCPBASABSBA
646/2646/
648
XH
↑
LX X
LH
↑↑
DIRGCPABCPBASABSBA
HL
↑
LL X
XH
STORAGE FROM
↑↑
A AND/OR B
XXX
↑
XX
XX
XXX
↑
XX
XX
2634 drw 08
652/2652GABGBACPABCPBASABSBA
HLH or H or HH
646/2646/
648
(1)
DIRGCPABCPBASABSBA
LLXH or XH
HLH or XHX
TRANSFER STORES
DATA TO A AND/OR B
2634 drw 09
NOTE:
1. 646/2646/648 cannot transfer data to A bus and B bus simultaneously.
6.204
IDT54/74FCT646/2646/652/2652T/AT/CT/DT, 648T/AT/CT
FAST CMOS OCTAL TRANSCEIVER/REGISTERMILITARY AND COMMERCIAL TEMPERATURE RANGES
(1)
SymbolDescriptionMax.Unit
(2)
V
TERM
Terminal Voltage with Respect to
–0.5 to +7.0V
GND
(3)
V
TERM
T
STG
I
OUT
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 with Respect to
GND
–0.5 to
V
Storage Temperature–65 to +150°C
DC Output Current–60 to +120 mA
CC by +0.5V unless otherwise noted.
CC terminals only.
CC
+0.5
2634 lnk 04
CAPACITANCE (TA = +25°C, f = 1.0MHz)ABSOLUTE MAXIMUM RATINGS
SymbolParameter
CINInput
Capacitance
V
COUTOutput
Capacitance
NOTE:
1. This parameter is measured at characterization but not tested.
(1)
ConditionsTyp.Max. Unit
VIN = 0V610pF
VOUT = 0V812pF
DC ELECTRICAL CHARACTERISTICS OVER OPERATING RANGE
Following Conditions Apply Unless Otherwise Specified:
Commercial: TA = –40°C to +85°C, VCC = 5.0V ± 5%; Military: TA = –55°C to +125°C, VCC = 5.0V ± 10%
SymbolParameterTest Conditions
(1)
Min.Typ.
VIHInput HIGH LevelGuaranteed Logic HIGH Level2.0——V
VILInput LOW LevelGuaranteed Logic LOW Level——0.8V
II HInput HIGH Current
II LInput LOW Current