SN54AS825A_15 Datasheet, PDF (1/10 Pages) Texas Instruments – 8-BIT BUS-INTERFACE FLIP-FLOPS WITH 3-STATE OUTPUTS

• Functionally Equivalent to AMD’s AM29825
• Improved I_OH Specifications
• Multiple Output Enables Allow Multiuser
Control of the Interface
• Outputs Have Undershoot-Protection
Circuitry
• Power-Up High-Impedance State
• Buffered Control Inputs Reduce dc
Loading Effects
• Package Options Include Plastic
Small-Outline (DW) Packages, Ceramic
Chip Carriers (FK), and Standard Plastic
(NT) and Ceramic (JT) 300-mil DIPs
description
SN54AS825A, SN74AS825A
8ĆBIT BUSĆINTERFACE FLIPĆFLOPS
WITH 3ĆSTATE OUTPUTS
SDAS020B − JUNE 1984 − REVISED AUGUST 1995
SN54AS825A . . . JT PACKAGE
SN74AS825A . . . DW OR NT PACKAGE
(TOP VIEW)
OE1 1
OE2 2
1D 3
2D 4
3D 5
4D 6
5D 7
6D 8
7D 9
8D 10
CLR 11
GND 12
24 V_CC
23 OE3
22 1Q
21 2Q
20 3Q
19 4Q
18 5Q
17 6Q
16 7Q
15 8Q
14 CLKEN
13 CLK
These 8-bit flip-flops feature 3-state outputs
designed specifically for driving highly capacitive
or relatively low-impedance loads. These devices
are particularly suitable for implementing
multiuser registers, I/O ports, bidirectional bus
drivers, and working registers.
With the clock-enable (CLKEN) input low, the
eight D-type edge-triggered flip-flops enter data
on the low-to-high transitions of the clock (CLK)
input. Taking CLKEN high disables the clock
buffer, latching the outputs. These devices have
noninverting data (D) inputs. Taking the clear
(CLR) input low causes the eight Q outputs to go
low independently of the clock.
SN54AS825A . . . FK PACKAGE
(TOP VIEW)
4 3 2 1 28 27 26
2D 5
25 2Q
3D 6
24 3Q
4D 7
23 4Q
NC 8
22 NC
5D ₉
21 5Q
6D ₁₀
20 6Q
7D ₁₁
19 7Q
12 13 14 15 16 17 18
Multiuser buffered output-enable (OE1, OE2, and
OE3) inputs can be used to place the eight outputs
in either a normal logic state (high or low logic
level) or a high-impedance state. In the
high-impedance state, the outputs neither load
nor drive the bus lines significantly. The high-
impedance state and increased drive provide the
capability to drive bus lines without interface or
pullup components.
NC − No internal connection
The output enables do not affect the internal operation of the flip-flops. Old data can be retained or new data
can be entered while the outputs are in the high-impedance state.
The SN54AS825A is characterized for operation over the full military temperature range of −55°C to 125°C. The
SN74AS825A is characterized for operation from 0°C to 70°C.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
Copyright  1995, Texas Instruments Incorporated
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