http://www.www.datasheet4u.com

900,000+ Datasheet PDF Search and Download

Datasheet4U offers most rated semiconductors datasheets pdf




Fairchild Semiconductor Electronic Components Datasheet

74191 Datasheet

Synchronous 4-Bit Up/Down Counter with Mode Control

No Preview Available !

74191 pdf
August 1986
Revised February 1999
DM74LS191
Synchronous 4-Bit Up/Down Counter with Mode Control
General Description
The DM74LS191 circuit is a synchronous, reversible, up/
down counter. Synchronous operation is provided by hav-
ing all flip-flops clocked simultaneously, so that the outputs
change simultaneously when so instructed by the steering
logic. This mode of operation eliminates the output count-
ing spikes normally associated with asynchronous (ripple
clock) counters.
The outputs of the four master-slave flip-flops are triggered
on a LOW-to-HIGH level transition of the clock input, if the
enable input is LOW. A HIGH at the enable input inhibits
counting. Level changes at either the enable input or the
down/up input should be made only when the clock input is
HIGH. The direction of the count is determined by the level
of the down/up input. When LOW, the counter counts up
and when HIGH, it counts down.
The counter is fully programmable; that is, the outputs may
be preset to either level by placing a LOW on the load input
and entering the desired data at the data inputs. The output
will change independent of the level of the clock input. This
feature allows the counters to be used as modulo-N divid-
ers by simply modifying the count length with the preset
inputs.
The clock, down/up, and load inputs are buffered to lower
the drive requirement; which significantly reduces the num-
ber of clock drivers, etc., required for long parallel words.
Two outputs have been made available to perform the cas-
cading function: ripple clock and maximum/minimum count.
The latter output produces a high-level output pulse with a
duration approximately equal to one complete cycle of the
clock when the counter overflows or underflows. The ripple
clock output produces a low-level output pulse equal in
width to the low-level portion of the clock input when an
overflow or underflow condition exists. The counters can be
easily cascaded by feeding the ripple clock output to the
enable input of the succeeding counter if parallel clocking
is used, or to the clock input if parallel enabling is used.
The maximum/minimum count output can be used to
accomplish look-ahead for high-speed operation.
Features
s Counts binary
s Single down/up count control line
s Count enable control input
s Ripple clock output for cascading
s Asynchronously presettable with load control
s Parallel outputs
s Cascadable for n-bit applications
s Average propagation delay 20 ns
s Typical clock frequency 25 MHz
s Typical power dissipation 100 mW
Ordering Code:
Order Number Package Number
Package Description
DM74LS191M
M16A
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150” Narrow Body
DM74LS191N
N16E
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300” Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
© 1999 Fairchild Semiconductor Corporation DS006405.prf
www.fairchildsemi.com


Fairchild Semiconductor Electronic Components Datasheet

74191 Datasheet

Synchronous 4-Bit Up/Down Counter with Mode Control

No Preview Available !

74191 pdf
Connection Diagram
Timing Diagram
www.fairchildsemi.com
2


Part Number 74191
Description Synchronous 4-Bit Up/Down Counter with Mode Control
Maker Fairchild Semiconductor
Total Page 6 Pages
PDF Download
74191 pdf
Download PDF File
74191 pdf
View for Mobile



Buy Electronic Components




Related Datasheet

1 74190 Synchronous Decade Up/Down Counters National Semiconductor
National Semiconductor
74190 pdf
2 74190 4 BIT SYNCHRONOUS UP/DOWN COUNTERS SGS-THOMSON
SGS-THOMSON
74190 pdf
3 74190 Synchronous Up/Down Counters With Down/Up Mode Control Texas Instruments
Texas Instruments
74190 pdf
4 74191 Synchronous 4-Bit Up/Down Counter with Mode Control Fairchild Semiconductor
Fairchild Semiconductor
74191 pdf
5 74191 Synchronous Up/Down 4-Bit Binary Counter with Mode Control National Semiconductor
National Semiconductor
74191 pdf
6 74191 4 BIT SYNCHRONOUS UP/DOWN COUNTERS SGS-THOMSON
SGS-THOMSON
74191 pdf
7 74191 Synchronous Up/Down Counters With Down/Up Mode Control Texas Instruments
Texas Instruments
74191 pdf
8 74192 SYNCHRONOUS UP/DOWN DECADE(/BINARY) COUNTER STMicroelectronics
STMicroelectronics
74192 pdf
9 74192 Up / Down Decade Counter National Semiconductor
National Semiconductor
74192 pdf






Part Number Start With

0    1    2    3    4    5    6    7    8    9    A    B    C    D    E    F    G    H    I    J    K    L    M    N    O    P    Q    R    S    T    U    V    W    X    Y    Z

site map

webmaste! click here

contact us

Buy Components