SN74AS1843 Datasheet, PDF (1/5 Pages) Texas Instruments – 9-BIT BUS INTERFACE D-TYPE LATCHES WITH 3-STATE OUTPUTS

SN74AS1843
9BIT BUS INTERFACE DTYPE LATCHES WITH 3STATE OUTPUTS
• Center V_CC and GND Configuration
Provides Minimum Lead Inductance in High
Current Switching Applications
• 3-State Buffer-Type Outputs Drive
Bus-Lines Directly
• Bus-Structured Pinout
• Provide Extra Bus Driving Latches
Necessary for Wider Address/Data Paths or
Buses With Parity
• Buffered Control Inputs to Reduce DC
Loading
• Power-Up High Impedance
• Package Options Include Plastic DIPs. Use
the ′AS843 for Plastic and Ceramic Chip
Carriers and “Small Outline” Package
Options
• Dependable Texas Instruments Quality and
Reliability
description
This 9-bit latch device features three-state outputs
designed specifically for driving highly capacitive
or relatively low-impedance loads. It is particularly
suitable for implementing buffer registers, I/O
ports, bidirectional bus drivers, and working
registers.
The nine latches are transparent D-type and have
noninverting data (D) inputs.
A buffered output control (OC) input can be used
to place the nine outputs in either a normal logic
state (high or low levels) 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 the bus lines in a
bus-organized system without need for interface
or pullup components.
The output control (OC) 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 off.
The SN74AS1843 is characterized for operation
from 0°C to 70°C.
SDAS127 − APRIL 1987
NT Package
(Top View)
5Q 1
4Q 2
3Q 3
2Q 4
1Q 5
VCC ⁶
OC ⁷
1D ⁸
2D ⁹
3D ¹⁰
4D ¹¹
5D ¹²
24 6Q
23 7Q
22 8Q
21 9Q
20 PRE
19 _C
18 _GND
17 _CLR
16 _9D
15 _8D
14 _7D
13 _6D
PRE
L
H
H
H
H
X
FUNCTION TABLE
INPUTS
CLR OC
C
D
X
L
X
X
L
L
X
X
H
L
H
L
H
L
H
H
H
L
L
X
X
H
X
X
OUTPUT
Q
H
L
L
H
QO
Z
logic symbol ^†
7
OC
EN
20
PRE
S2
17
CLR
R
19
C
C1
1D ⁸
1D
9
2D
10
3D
11
4D
12
5D
13
6D
14
7D
15
8D
16
9D
2
5
1Q
4
2Q
3
3Q
2
4Q
1
5Q
24
6Q
23
7Q
22
8Q
21
9Q
† This symbol is in accordance with ANSI/IEEE Std 91-1984
and IEC Publication 617-12,
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  1987, Texas Instruments Incorporated
• POST OFFICE BOX 655303 DALLAS, TEXAS 75265
1