© 2000 Fairchild Semiconductor Corporation

DS009789

www.fairchildsemi.com

June 1988

Revised October 2000

74AC399 • 74ACT399

Quad 2-Port Register

General Description

The AC/ACT399 is the logical equivalent of a quad 2-input

multiplexer feeding into four edge-triggered flip-flops. A

common Select input determines which of the two 4-bit

words is accepted. The selected data enters the flip-flop on

the rising edge of the clock.

Features

s Select inputs from two data sources

s Fully positive edge-triggered operation

s Outputs source/sink 24 mA

s AC/ACT399 has TTL-compatible inputs

Ordering Code:

Device also available in Tape and Reel. Specify by appending suffix letter “X” to the ordering code.

Logic Symbols

IEEE/IEC

Connection Diagram

Pin Descriptions

FACT

 is a trademark of Fairchild Semiconductor Corporation.

Order Number

Package Number

Package Description

74AC399SC

M16A

16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow

74AC399PC

N16E

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

74ACT399SC

M16A

16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow

74ACT399SJ

M16D

16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide

74ACT399MTC

MTC16

16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide

74ACT399PC

N16E

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

Pin Names

Description

S

Common Select Input

CP

Clock Pulse Input

Data Inputs from Source 0

Data Inputs from Source 1

Register True Outputs