FAST CMOS OCTAL
TRANSCEIVER/
REGISTERS (3-STATE)
Integrated Device Technology, Inc.
IDT54/74FCT646T/AT/CT/DT - 2646T/AT/CT
IDT54/74FCT648T/AT/CT
IDT54/74FCT652T/AT/CT/DT - 2652T/AT/CT
FEATURES:
鈥?Common features:
鈥?Low input and output leakage
鈮?碌A
(max.)
鈥?Extended commercial range of 鈥?0擄C to +85擄C
鈥?CMOS power levels
鈥?True TTL input and output compatibility
鈥?V
OH
= 3.3V (typ.)
鈥?V
OL
= 0.3V (typ.)
鈥?Meets or exceeds JEDEC standard 18 specifications
鈥?Product available in Radiation Tolerant and Radiation
Enhanced versions
鈥?Military product compliant to MIL-STD-883, Class B
and DESC listed (dual marked)
鈥?Available in DIP, SOIC, SSOP, QSOP, TSSOP,
CERPACK and LCC packages
鈥?Features for FCT646T/648T/652T:
鈥?Std., A, C and D speed grades
鈥?High drive outputs (-15mA I
OH
, 64mA I
OL
)
鈥?Power off disable outputs permit 鈥渓ive insertion鈥?/div>
鈥?Features for FCT2646T/2652T:
鈥?Std., A, and C speed grades
鈥?Resistor outputs (-15mA I
OH
, 12mA I
OL
Com.)
(-12mA I
OH
, 12mA I
OL
Mil.)
鈥?Reduced system switching noise
DESCRIPTION:
The FCT646T/FCT2646T/FCT648T/FCT652T/2652T con-
sist 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 regis-
ters.
The FCT652T/FCT2652T utilize GAB and
GBA
signals to
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 real-
time 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 real-
time 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 appro-
priate 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.
IDT54/74FCT652/2652
ONLY
GBA
GAB
FUNCTIONAL BLOCK DIAGRAM
IDT54/74FCT646/2646/648
ONLY
G
DIR
CPBA
SBA
CPAB
SAB
B REG
1 OF 8 CHANNELS
1D
C1
646/2646/652/2652
ONLY
A1
A REG
1D
C1
B1
646/2646/652/2652
ONLY
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
2634 drw 01
TO 7 OTHER CHANNELS
MILITARY AND COMMERCIAL TEMPERATURE RANGES
漏1996
Integrated Device Technology, Inc.
SEPTEMBER 1996
DSC-2634/9
6.20
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