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National Semiconductor Electronic Components Datasheet

DM54LS461 Datasheet

Octal Counter

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July 1989
DM54LS461 DM74LS461 Octal Counter
General Description
The LS461 is an 8-bit synchronous counter with parallel
load clear and hold capability Two function select inputs
(I0 I1) provide one of four operations which occur synchro-
nously on the rising edge of the clock (CK)
The LOAD operation loads the inputs (D7 – D0) into the out-
put register (Q7 – Q0) The CLEAR operation resets the out-
put register to all LOWs The HOLD operation holds the
previous value regardless of clock transitions The INCRE-
MENT operation adds one to the output register when the
carry-in input is TRUE (CI e LOW) otherwise the operation
is a HOLD The carry-out (CO) is TRUE (CO e LOW) when
the output register (Q7 – Q0) is all HIGHs otherwise FALSE
(CO e HIGH)
The output register (Q7 – Q0) is enabled when OE is LOW
and disabled (HI-Z) when OE is HIGH The output drivers
will sink the 24 mA required for many bus interface stand-
ards
Connection Diagram
Two or more LS461 octal counters may be cascaded to
provide larger counters The operation codes were chosen
such that when I1 is HIGH I0 may be used to select be-
tween LOAD and INCREMENT as in a program counter
(JUMP INCREMENT)
Features Benefits
Y Octal counter for microprogram-counter DMA controller
and general purpose counting applications
Y 8 bits match byte boundaries
Y Bus-structured pinout
Y 24-pin Skinny Dip saves space
Y TRI-STATE outputs drive bus lines
Y Low current PNP inputs reduce loading
Y Expandable in 8-bit increments
Standard Test Load
Top View
TL L 8334 – 2
TL L 8334 – 1
Order Number DM54LS461J
DM74LS461J or DM74LS461N
See NS Package Number J24F or N24C
Function Table
OE CK I1 I0 CI D7 – D0 Q7 – Q0 Operation
H X XXX X
Z
HI-Z
uL L L X X L CLEAR
L uLHX X
Q
HOLD
L uHL X D
D
LOAD
L uHHH X
Q
HOLD
uL H H L X Q plus 1 INCREMENT
TRI-STATE is a registered trademark of National Semiconductor Corp
C1995 National Semiconductor Corporation TL L 8334
RRD-B30M115 Printed in U S A


National Semiconductor Electronic Components Datasheet

DM54LS461 Datasheet

Octal Counter

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 C 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
Low
High
Min
45
b55
40
30
60
0
Military
Typ
5
b15
Max
55
125
Commercial
Min Typ Max
4 75 5 5 25
0 75
35
25
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
VOL
Low-Level Output Voltage
VCCeMIN
VILe0 8V
MIL IOLe12 mA
VIHe2V
COM
IOLe24 mA
VOH
High-Level Output Voltage
VCCeMIN
VILe0 8V
VIHe2V
MIL
COM
IOHeb2 mA
IOHeb3 2 mA
24
IOZL
IOZH
Off-State Output Current
VCCeMAX
VILe0 8V
VIHe2V
VOe0 4V
VOe2 4V
IOS Output Short-Circuit Current VCCe5 0V
VCCe0V
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
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
Switching Characteristics Over Operating Conditions
Symbol
Parameter
Test Conditions
(See Test Load)
Min
fMAX
tPD
tPD
tPD
tPZX
tPXZ
Maximum Clock Frequency
CBI to CBO Delay
Clock to Q
Clock to CO
Output Enable Delay
Output Disable Delay
CLe50 pF
R1e200 X
R2e390 X
10 5
Military
Typ
35
20
55
35
35
Max
60
35
95
55
55
Commercial
Min Typ Max
12 5
35 50
20 30
55 80
35 45
35 45
Units
MHz
ns
ns
ns
ns
ns
2


Part Number DM54LS461
Description Octal Counter
Maker National Semiconductor
PDF Download

DM54LS461 Datasheet PDF






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