Integrated Device Technology, Inc.
FAST CMOS OCTAL IDT54/74FCT646T/AT/CT/DT - 2646T/AT/CT
IDT54/74FCT652T/AT/CT/DT - 2652T/AT/CT
• Common features:
– 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
– VOH = 3.3V (typ.)
– VOL = 0.3V (typ.)
– Meets or exceeds JEDEC standard 18 specifications
– Product available in Radiation Tolerant and Radiation
– 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
FUNCTIONAL BLOCK DIAGRAM
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-
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.
1 OF 8 CHANNELS
A1 A REG
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
TO 7 OTHER CHANNELS
MILITARY AND COMMERCIAL TEMPERATURE RANGES
©1996 Integrated Device Technology, Inc.
2634 drw 01