SN54ALS29821 Datasheet, PDF (1/6 Pages) Texas Instruments – 10-BIT BUS-INTERFACE FLIP-FLOPS WITH 3-STATE OUTPUTS

SN54ALS29821, SN74ALS29821
10-BIT BUS-INTERFACE FLIP-FLOPS
WITH 3-STATE OUTPUTS
SDAS145B – JANUARY 1986 – REVISED JANUARY 1995
• Functionally Equivalent to AMD’s AM29821
• Provide Extra Data Width Necessary for
Wider Address/Data Paths or Buses With
SN54ALS29821 . . . JT PACKAGE
SN74ALS29821 . . . DW OR NT PACKAGE
(TOP VIEW)
Parity
• Outputs Have Undershoot-Protection
Circuitry
• Power-Up High-Impedance State
OE 1
1D 2
2D 3
3D 4
24 V_CC
23 1Q
22 2Q
21 3Q
• Buffered Control Inputs Reduce
dc Loading Effects
• Package Options Include Plastic
Small-Outline (DW) Packages and Standard
Plastic (NT) and Ceramic (JT) 300-mil DIPs
4D 5
5D 6
6D 7
7D 8
8D 9
9D 10
20 4Q
19 5Q
18 6Q
17 7Q
16 8Q
15 9Q
description
These 10-bit edge-triggered D-type flip-flops
10D 11
GND 12
14 10Q
13 CLK
feature 3-state outputs designed specifically for
driving highly capacitive or relatively low-impedance loads. These devices are particularly suitable for
implementing wider buffer registers, I/O ports, bidirectional bus drivers with parity, and working registers.
On the positive transition of the clock (CLK) input, the Q outputs are true to the data (D) input.
A buffered output-enable (OE) input can place the ten outputs in either a normal logic state (high or low logic
levels) or a high-impedance state. The outputs also are in the high-impedance state during power-up and
power-down conditions. The outputs remain in the high-impedance state while the device is powered down. 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.
OE does 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 SN54ALS29821 is characterized for operation over the full military temperature range of – 55°C to 125°C.
The SN74ALS29821 is characterized for operation from 0°C to 70°C.
FUNCTION TABLE
(each flip-flop)
INPUTS
OE CLK D
OUTPUT
Q
L
↑
H
H
L
↑
L
L
L
L
X
Q0
H
X
X
Z
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.
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Copyright © 1995, Texas Instruments Incorporated
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