DM74LS491 Datasheet PDF - National Semiconductor

www.Datasheet-PDF.com

DM74LS491
National Semiconductor

Part Number DM74LS491
Description 10-Bit Counter
Page 4 Pages


DM74LS491 datasheet pdf
View PDF for PC
DM74LS491 pdf
View PDF for Mobile


No Preview Available !

July 1989
DM54LS491 74LS491 10-Bit Counter
General Description
The ten-bit counter can count up count down set and load
2 LSB’s 2 MSB’s and 6 middle bits high or low as a group
All operations are synchronous with the clock SET over-
rides LOAD COUNT and HOLD LOAD overrides COUNT
COUNT is conditional on CIN otherwise it holds
All outputs are enabled when OE is low otherwise HIGH-Z
The 24 mA IOL outputs are suitable for driving RAM PROM
address lines in video graphics systems
Features Benefits
Y CRT vertical and horizontal timing generation
Y Bus-structured pinout
Y 24-pin SKINNYDIP saves space
Y TRI-STATE outputs drive bus lines
Y Low current PNP inputs reduce loading
Connection Diagram
Standard Test Load
Top View
TL L 8332 – 2
TL L 8332 – 1
Order Number DM54LS491J
DM74LS491J or DM74LS491N
See NS Package Number J24F or N24C
Function Table
OE CK SET LD CNT CIN UP D9-D0 Q9-Q0 Operation
HX X X X XX
Lu H X X X X
Lu L L X X X
Lu L H H X X
Lu L H L H X
Lu L H L L L
Lu L H L L H
X Z Hi-Z
X H Set all HIGH
D D LOAD D
X Q HOLD
X Q HOLD
X Q plus 1 Count UP
X Q minus 1 Count DN
TRI-STATE is a registered trademark of National Semiconductor Corp
C1995 National Semiconductor Corporation TL L 8332
RRD-B30M115 Printed in U S A



No Preview Available !

Absolute Maximum Ratings
If Military Aerospace specified devices are required
please contact the National Semiconductor Sales
Office Distributors for availability and specifications
Supply Voltage VCC
Input Voltage
7V
5 5V
Off-State Output Voltage
Storage Temperature
5 5V
b65 to a150 C
Operating Conditions
Symbol
Parameter
VCC Supply Voltage
TA Operating Free-Air Temperature
tw Width of Clock
tSU Set-Up Time
th Hold Time
Case temperature
High
Low
Min
45
b55
40
35
60
0
Military
Typ
5
b15
Max
55
125
Commercial
Min Typ Max
4 75 5 5 25
0 75
40
35
50
0 b15
Units
V
C
ns
ns
Electrical Characteristics Over Operating Conditions
Symbol
Parameter
Test Conditions
Min
VIL Low-Level Input Voltage
VIH High-Level Input Voltage
2
VIC Input Clamp Voltage
VCCeMIN IIeb18 mA
IIL
Low-Level Input Current
VCCeMAX VIe0 4V
IIH
High-Level Input Current
VCCeMAX VIe2 4V
II
Maximum Input Current
VCCeMAX VIe5 5V
VCCeMIN
MIL
VOL
Low-Level Output Voltage
VILe0 8V
VIHe2V
COM
IOLe12 mA
IOLe24 mA
VOH
High-Level Output Voltage
VCCeMIN
VILe0 8V
VIHe2V
MIL
COM
IOHeb2 mA
IOHe3 2 mA
24
IOZL
IOZH
Off-State Output Current
VCCeMAX
VILe0 8V
VIHe2V
VOe0 4V
VOe2 4V
IOS Output Short-Circuit Current VCCe5 0V
VOe0V
b30
ICC Supply Current
VCCeMAX
No more than one output should be shorted at a time and duration of the short-circuit should not exceed one second
All typical values are at VCCe5V TAe25 C
Switching Characteristics Over Operating Conditions
Typ
120
Max
08
b1 5
b0 25
25
1
Units
V
V
V
mA
mA
mA
05 V
V
b100
100
b130
180
mA
mA
mA
mA
Symbol
fMAX
tPD
tPZX
tPXZ
Parameter
Maximum Clock Frequency
Clock to Q
Output Enable Delay
Output Disable Delay
Test Conditions
(See Test Load)
CLe50 pF
R1e200X
R2e390X
Military
Min Typ Max
10 5
20 35
35 55
35 55
Commercial
Min Typ Max
12 5
20 30
35 45
35 45
Units
MHz
ns
ns
ns
2



No Preview Available !

Logic Diagram
10-Bit Up Down Counter
TL L 8332 – 3
3



No Preview Available !

Physical Dimensions inches (millimeters)
24-Pin Narrow Ceramic Dual-In-Line Package (J)
Order Number DM54LS491J or DM74LS491J
NS Package Number J24F
LIFE SUPPORT POLICY
24-Pin Narrow Plastic Dual-In-Line Package (N)
Order Number DM74LS491N
NS Package Number N24C
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL
SEMICONDUCTOR CORPORATION As used herein
1 Life support devices or systems are devices or
systems which (a) are intended for surgical implant
into the body or (b) support or sustain life and whose
failure to perform when properly used in accordance
with instructions for use provided in the labeling can
be reasonably expected to result in a significant injury
to the user
2 A critical component is any component of a life
support device or system whose failure to perform can
be reasonably expected to cause the failure of the life
support device or system or to affect its safety or
effectiveness
National Semiconductor
Corporation
1111 West Bardin Road
Arlington TX 76017
Tel 1(800) 272-9959
Fax 1(800) 737-7018
National Semiconductor
Europe
Fax (a49) 0-180-530 85 86
Email cnjwge tevm2 nsc com
Deutsch Tel (a49) 0-180-530 85 85
English Tel (a49) 0-180-532 78 32
Fran ais Tel (a49) 0-180-532 93 58
Italiano Tel (a49) 0-180-534 16 80
National Semiconductor
Hong Kong Ltd
13th Floor Straight Block
Ocean Centre 5 Canton Rd
Tsimshatsui Kowloon
Hong Kong
Tel (852) 2737-1600
Fax (852) 2736-9960
National Semiconductor
Japan Ltd
Tel 81-043-299-2309
Fax 81-043-299-2408
National does not assume any responsibility for use of any circuitry described no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications



DM74LS491 datasheet pdf
Download PDF
DM74LS491 pdf
View PDF for Mobile


Related : Start with DM74LS49 Part Numbers by
DM74LS49 BCD/7-Segment Decoder/Driver DM74LS49
MSI
DM74LS49 pdf
DM74LS491 10-Bit Counter DM74LS491
National Semiconductor
DM74LS491 pdf

Index :   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   

This is a individually operated, non profit site. If this site is good enough to show, please introduce this site to others.
Since 2010   ::   HOME   ::   Privacy Policy + Contact