74LS168

Manufacturer Part Number74LS168
Description54LS168 Synchronous Bi-Directional BCD Decade Counter
ManufacturerNational Semiconductor
74LS168 datasheet
 


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54LS168 Synchronous Bi-Directional
BCD Decade Counter
General Description
The 54LS168 is a fully synchronous 4-state up down coun-
ter featuring a preset capability for programmable operation
carry lookahead for easy cascading and a U D input to con-
trol the direction of counting It counts in the BCD (8421)
sequence and all state changes whether in counting or par-
allel loading are initiated by the LOW-to-HIGH transition of
the clock
Connection Diagram
Dual-In-Line Package
Order Number 54LS168DMQB
54LS168FMQB or 54LS168LMQB
See NS Package Number
E20A J16A or W16A
Pin Names
CEP
CET
CP
P0–P3
PE
U D
Q0–Q3
TC
C 1995 National Semiconductor Corporation
TL F 10207
Logic Symbol
TL F 10207– 1
V
e
CC
GND
Description
Count Enable Parallel Input (Active LOW)
Count Enable Trickle Input (Active LOW)
Clock Pulse Input (Active Rising Edge)
Parallel Data Inputs
Parallel Enable Input (Active LOW)
Up-Down Count Control Input
Flip-Flop Outputs
Terminal Count Output (Active LOW)
June 1989
TL F 10207– 2
Pin 16
Pin 8
e
RRD-B30M105 Printed in U S A

74LS168 Summary of contents

  • Page 1

    ... See NS Package Number E20A J16A or W16A Pin Names CEP CET CP P0– Q0– 1995 National Semiconductor Corporation TL F 10207 Logic Symbol TL F 10207– GND Description Count Enable Parallel Input (Active LOW) Count Enable Trickle Input (Active LOW) ...

  • Page 2

    ... Absolute Maximum Ratings If Military Aerospace specified devices are required please contact the National Semiconductor Sales Office Distributors for availability and specifications Supply Voltage Input Voltage Operating Free Air Temperature Range 54LS Storage Temperature Range Recommended Operating Conditions ...

  • Page 3

    Electrical Characteristics Symbol Parameter V Input Clamp Voltage I V High Level Output Voltage OH V Low Level Output Voltage OL I Input Current Max I Input Voltage I High Level Input Current IH I Low Level Input Current IL ...

  • Page 4

    Functional Description The ’LS168 uses edge-triggered D-type flip-flops and has no constraints on changing the control or data input signals in either state of the Clock The only requirement is that the various inputs attain the desired state at least ...

  • Page 5

    Physical Dimensions inches (millimeters) Ceramic Leadless Chip Carrier Package (E) 16-Lead Ceramic Dual-In-Line Package (J) Order Number 54LS168LMQB NS Package Number E20A Order Number 54LS168DMQB NS Package Number J16A 5 ...

  • Page 6

    ... Hong Kong Ltd 49) 0-180-530 85 86 13th Floor Straight Block a Ocean Centre 5 Canton Rd 49) 0-180-530 85 85 Tsimshatsui Kowloon a Tel ( 49) 0-180-532 78 32 Hong Kong a 49) 0-180-532 93 58 Tel (852) 2737-1600 a Tel ( 49) 0-180-534 16 80 Fax (852) 2736-9960 a National Semiconductor Japan Ltd Tel 81-043-299-2309 Fax 81-043-299-2408 ...