®
Integrated Device Technology, Inc.
HIGH-PERFORMANCE
CMOS BUS INTERFACE
REGISTERS
IDT54/74FCT821A/B/C
IDT54/74FCT823A/B/C
IDT54/74FCT824A/B/C
IDT54/74FCT825A/B/C
FEATURES:
• Equivalent to AMD’s Am29821-25 bipolar registers in
pinout/function, speed and output drive over full tem-
perature and voltage supply extremes
• IDT54/74FCT821A/823A/824A/825A equivalent to
FAST™ speed
• IDT54/74FCT821B/823B/824B/825B 25% faster than
FAST
• IDT54/74FCT821C/823C/824C/825C 40% faster than
FAST
• Buffered common Clock Enable (EN) and asynchronous
Clear input (CLR)
• IOL = 48mA (commercial) and 32mA (military)
• Clamp diodes on all inputs for ringing suppression
• CMOS power levels (1mW typ. static)
• TTL input and output compatibility
• CMOS output level compatible
• Substantially lower input current levels than AMD’s
bipolar Am29800 series (5µA max.)
• Product available in Radiation Tolerant and Radiation
Enhanced versions
• Military product compliant to MIL-STD-883, Class B
DESCRIPTION:
The IDT54/74FCT800 series is built using an advanced
dual metal CMOS technology.
The IDT54/74FCT820 series bus interface registers are
designed to eliminate the extra packages required to buffer
existing registers and provide extra data width for wider
address/data paths or buses carrying parity. The IDT54/
74FCT821 are buffered, 10-bit wide versions of the popular
‘374 function. The IDT54/74FCT823 and IDT54/74FCT824
are 9-bit wide buffered registers with Clock Enable (EN) and
Clear (CLR) – ideal for parity bus interfacing in high-perform-
ance microprogrammed systems. The IDT54/74FCT825 are
8-bit buffered registers with all the ‘823 controls plus multiple
enables (OE1, OE2, OE3) to allow multiuser control of the
interface, e.g., CS, DMA and RD/WR. They are ideal for use
as an output port requiring HIGH IOL/IOH.
All of the IDT54/74FCT800 high-performance interface
family are designed for high-capacitance load drive capability,
while providing low-capacitance bus loading at both inputs
and outputs. All inputs have clamp diodes and all outputs are
designed for low-capacitance bus loading in high-impedance
state.
FUNCTIONAL BLOCK DIAGRAMS
IDT54/74FCT821/823/825
D0 DN
EN
IDT54/74FCT824
D0
EN
DN
CLR
CP
D CL Q
CP Q
D CL Q
CP Q
CLR
CP
OE
Y0
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
FAST is a trademark of National Semiconductor Co.
YN
2608 cnv* 01
MILITARY AND COMMERCIAL TEMPERATURE RANGES
©1992 Integrated Device Technology, Inc.
7.19
OE
D CL Q
CP Q
D CL Q
CP Q
Y0 YN
2608 cnv* 02
MAY 1992
DSC-4618/2
1
