74AC191 Datasheet, PDF (1/10 Pages) Fairchild Semiconductor – 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—133 MHz typical count frequency
s Synchronous counting
s Asynchronous parallel load
s Cascadable
s Outputs source/sink 24 mA
Ordering Code:
Order Number Package Number
Package Description
74AC191SC
M16A
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150” Narrow Body
74AC191SJ
M16D
16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
74AC191MTC
MTC16
16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
74AC191PC
N16E
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300” Wide
Device also available in Tape and Reel. Specify by appending suffix letter “X” to the ordering code.
Logic Symbols
Connection Diagram
IEEE/IEC
Pin Descriptions
Pin Names
CE
CP
P₀–P₃
PL
U /D
Q₀–Q₃
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
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