October 1987

Revised April 2002

CD4099

8-Bit Addressable Latch

General Description

The CD4099BC is an 8-bit addressable latch with three

address inputs (A0–A2), an active low enable input (E),

active high clear input (CL), a data input (D), and eight out-

puts (Q0–Q7).

Data is entered into a particular bit in the latch when that bit

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 active output which follows the data input while all

unaddressed bits are held LOW. When operating in the

addressable latch mode (E

= CL = 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

= HIGH, CL = LOW).

Features

s Wide supply voltage range:

3.0V to 15V

s High noise immunity: 0.45 VDD (typ.)

s Low power TTL: fan out of 2 driving 74L

compatibility:

or 1 driving 74LS

s Serial to parallel capability

s Storage register capability

s Random (addressable) data entry

s Active high demultiplexing capability

s Common active high clear

Ordering Code:

Connection Diagram

Top View

Truth Table

Order Number

Package Number

Package Description

CD4099BCN

N16E

16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide

Mode Selection

E CL

Addressed

Unaddressed

Mode

Latch

Latch

L

L

Follows Data

Holds Previous Data Addressable Latch

H

L

Holds Previous Data Holds Previous Data Memory

L

H

Follows Data

Reset to “0”

Demultiplexer

H

H

Reset to “0”

Reset to “0”

Clear

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