SN74ALS29845 Datasheet, PDF (1/7 Pages) Texas Instruments – 8-BIT BUS INTERFACE D-TYPE LATCHES WITH 3-STATE OUTPUTS

SN74ALS29845, SN74ALS29846
8ĆBIT BUS INTERFACE DĆTYPE LATCHES WITH 3ĆSTATE OUTPUTS
• 3-State Buffer-Type Outputs Drive Bus
Lines Directly
• Bus-Structured Pinout
• Provides 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 State
• Package Options Include Plastic “Small
Outline” Packages, Plastic Chip Carriers,
and Standard Plastic 300-mil DIPs
• Dependable Texas Instruments Quality and
Reliability
description
These 8-bit latches feature three-state outputs
designed specifically for driving highly capacitive
or relatively low-impedance loads. They are
particularly suitable for implementing buffer
registers, I/O ports, bidirectional bus drivers, and
working registers.
The eight latches are transparent D-type. The
′ALS29845 has noninverting data (D) inputs. The
′ALS29846 has inverting D inputs. Since CLR and
PRE are independent of the clock, taking the CLR
input low will cause the eight Q outputs to go low.
Taking the PRE input low will cause the eight Q
outputs to go high. When both PRE and CLR are
taken low, the outputs will follow the preset
condition.
The buffered output control inputs (OC1, OC2,
and OC3) can be used to place the eight outputs
in either a normal logic state (high or low levels) or
a high-impedance state. The outputs are also 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 the
bus lines in a bus-organized system without need
SDAS150 − D3118 — JUNE 1988
SN74ALS29845 . . . DW or NT Package
(Top View)
OC1 1
OC2 2
1D 3
2D 4
3D 5
4D 6
5D 7
6D 8
7D 9
8D 10
CLR 11
GND 12
24 VCC
23 OC3
22 1Q
21 2Q
20 3Q
19 4Q
18 5Q
17 6Q
16 7Q
15 8Q
14 PRE
13 C
SN74ALS29845 . . . FN 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
SN74ALS29846 . . . DW or NT Package
(Top View)
OC1 1
OC2 2
1D 3
2D 4
3D 5
4D 6
5D 7
6D 8
7D 9
8D 10
CLR 11
GND 12
24 VCC
23 OC3
22 1Q
21 2Q
20 3Q
19 4Q
18 5Q
17 6Q
16 7Q
15 8Q
14 PRE
13 C
SN74ALS29846 . . . FN 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
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.
NC — No internal connection
Copyright  1988, Texas Instruments Incorporated
• POST OFFICE BOX 655303 DALLAS, TEXAS 75265
1