74AC191 Up/Down Counter with Preset and Ripple Clock
November 1988
Revised November 1999
74AC191
Up/Down Counter with Preset and Ripple Clock
General Description
The AC191 is a reversible modulo 16 binary counter. It fea-
tures synchronous counting and asynchronous presetting.
The preset feature allows the AC191 to be used in pro-
grammable dividers. The Count Enable input, the Terminal
Count output and the Ripple Clock output make possible a
variety of methods of implementing multistage counters. In
the counting modes, state changes are initiated by the ris-
ing edge of the clock.
Features
s
I
CC
reduced by 50%
s
High speed鈥?33 MHz typical count frequency
s
Synchronous counting
s
Asynchronous parallel load
s
Cascadable
s
Outputs source/sink 24 mA
Ordering Code:
Order Number
74AC191SC
74AC191SJ
74AC191MTC
74AC191PC
Package Number
M16A
M16D
MTC16
N16E
Package Description
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150鈥?Narrow Body
16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300鈥?Wide
Device also available in Tape and Reel. Specify by appending suffix letter 鈥淴鈥?to the ordering code.
Logic Symbols
Connection Diagram
IEEE/IEC
Pin Descriptions
Pin Names
CE
CP
P
0
鈥揚
3
PL
U /D
Q
0
鈥換
3
RC
TC
Description
Count Enable Input
Clock Pulse Input
Parallel Data Inputs
Asynchronous Parallel Load Input
Up/Down Count Control Input
Flip-Flop Outputs
Ripple Clock Output
Terminal Count Output
FACT錚?is a trademark of Fairchild Semiconductor Corporation.
漏 1999 Fairchild Semiconductor Corporation
DS009940
www.fairchildsemi.com