TL/F/6003
C
C
February 1988
CD4723BM/CD4723BC Dual 4-Bit Addressable Latch
CD4724BM/CD4724BC 8-Bit Addressable Latch
General Description
The CD4723B is a dual 4-bit addressable latch with com-
mon control inputs, including two address inputs (A0, A1),
an active low enable input (E), and an active high clear input
(CL). Each latch has a data input (D) and four outputs (Q0–
Q3). The CD4724B is an 8-bit addressable latch with three
address inputs (A0–A2), an active low enable input (E), ac-
tive high clear input (CL), a data input (D) and eight outputs
(Q0–Q7).
Data is entered into a particular bit in the latch when that is
addressed by the address inputs and the enable (E) is low.
Data entry is inhibited when enable (E) is high.
When clear (CL) and enable (E) are high, all outputs are low.
When clear (CL) is high and enable (E) is low, the channel
demultiplexing occurs. The bit that is addressed has an ac-
tive output which follows the data input while all unad-
dressed bits are held low. When operating in the address-
able latch mode (E
e
CL
e
low), changing more than one
bit of the address could impose a transient wrong address.
Therefore, this should only be done while in the memory
mode (E
e
high, CL
e
low).
Features
Y
Wide supply voltage range
3.0V to 15V
0.45 V
DD
(typ.)
Y
High noise immunity
Y
Low power TTL
compatibility
fan out of 2 driving 74L
or 1 driving 74LS
Y
Serial to parallel capability
Y
Storage register capability
Y
Random (addressable) data entry
Y
Active high demultiplexing capability
Y
Common active high clear
Connection Diagrams
CD4723B
Dual-In-Line Package
TL/F/6003–1
Top View
CD4724B
Dual-In-Line Package
TL/F/6003–2
Top View
Order Number CD4723B or
CD4724B
Truth Table
Mode Selection
E
CL
Addressed
Latch
Unaddressed
Latch
Mode
L
H
L
H
L
L
H
H
Follows Data
Hold Previous Data
Follows Data
Reset to ‘0’’
Holds Previous Data
Holds Previous Data
Reset to ‘‘0’’
Reset to ‘‘0’’
Addressable Latch
Memory
Demultiplexer
Clear
C
1995 National Semiconductor Corporation
RRD-B30M105/Printed in U. S. A.