Datenblatt-pdf.com


DM74ALS162B Schematic ( PDF Datasheet ) - Fairchild Semiconductor

Teilenummer DM74ALS162B
Beschreibung Synchronous Four-Bit Counter
Hersteller Fairchild Semiconductor
Logo Fairchild Semiconductor Logo 




Gesamt 9 Seiten
DM74ALS162B Datasheet, Funktion
April 1984
Revised February 2000
DM74ALS161B • DM74ALS162B • DM74ALS163B
Synchronous Four-Bit Counter
General Description
These synchronous presettable counters feature an inter-
nal carry look ahead for application in high speed counting
designs. The DM74ALS162B is a four-bit decade counter,
while the DM74ALS161B and DM74ALS163B are four-bit
binary counters. The DM74ALS161B clears asynchro-
nously, while the DM74ALS162B and DM74ALS163B clear
synchronously. The carry output is decoded to prevent
spikes during normal counting mode of operation. Synchro-
nous operation is provided by having all flip-flops clocked
simultaneously so that outputs change coincident with
each other when so instructed by count enable inputs and
internal gating. This mode of operation eliminates the out-
put counting spikes which are normally associated with
asynchronous (ripple clock) counters. A buffered clock
input triggers the four flip-flops on the rising (positive-
going) edge of the clock input waveform.
These counters are fully programmable, that is, the outputs
may be preset to either level. As presetting is synchronous,
setting up a low level at the load input disables the counter
and causes the outputs to agree with set up data after the
next clock pulse regardless of the levels of enable input.
LOW-to-HIGH transitions at the load input are perfectly
acceptable regardless of the logic levels on the clock or
enable inputs.
The DM74ALS161B clear function is asynchronous. A low
level at the clear input sets all four of the flip-flop outputs
LOW regardless of the levels of clock, load or enable
inputs. These two counters are provided with a clear on
power-up feature. The DM74ALS162B and DM74ALS163B
clear function is synchronous; and a low level at the clear
input sets all four of the flip-flop outputs LOW after the next
clock pulse, regardless of the levels of enable inputs. This
synchronous clear allows the count length to be modified
easily, as decoding the maximum count desired can be
accomplished with one external NAND gate. The gate out-
put is connected to the clear input to synchronously clear
the counter to all low outputs. LOW-to-HIGH transitions at
the clear input of the DM74ALS162B and DM74ALS163B
are also permissible regardless of the levels of logic on the
clock, enable or load inputs.
The carry look ahead circuitry provides for cascading
counters for n bit synchronous application without addi-
tional gating. Instrumental in accomplishing this function
are two count enable inputs (P and T) and a ripple carry
output. Both count enable inputs must be HIGH to count.
The T input is fed forward to enable the ripple carry output.
The ripple carry output thus enabled will produce a high
level output pulse with a duration approximately equal to
the high level portion of QA output. This high level overflow
ripple carry pulse can be used to enable successive cas-
caded stages. HIGH-to-LOW level transitions at the enable
P or T inputs of the DM74ALS161B through
DM74ALS163B may occur regardless of the logic level on
the clock.
The DM74ALS161B through DM74ALS163B feature a fully
independent clock circuit. changes made to control inputs
(enable P or T, or load) that will modify the operating mode
will have no effect until clocking occurs. The function of the
counter (whether enabled, disabled, loading or counting)
will be dictated solely by the conditions meeting the stable
set-up and hold times.
Features
s Switching specifications at 50 pF
s Switching specifications guaranteed over full tempera-
ture and VCC range
s Advanced oxide-isolated, ion-implanted Schottky TTL
process
s Functionally and pin-for-pin compatible with Schottky
and low power Schottky TTL counterpart
s Improved AC performance over Schottky and low power
Schottky counterparts
s Synchronously programmable
s Internal look ahead for fast counting
s Carry output for n-bit cascading
s Synchronous counting
s Load control line
s ESD inputs
Ordering Code:
Order Number Package Number
Package Description
DM74ALS161BM
M16A
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
DM74ALS161BN
N16E
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
DM74ALS162BM
M16A
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
DM74ALS162BN
N16E
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
DM74ALS163BM
M16A
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
DM74ALS163BN
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.
© 2000 Fairchild Semiconductor Corporation DS006206
www.fairchildsemi.com






DM74ALS162B Datasheet, Funktion
Absolute Maximum Ratings(Note 1)
Supply Voltage
Input Voltage
Operating Free Air Temperature Range
Storage Temperature Range
Typical θJA
N Package
M Package
7V
7V
0°C to +70°C
65°C to +150°C
78.1°C/W
106.8°C/W
Note 1: The “Absolute Maximum Ratings” are those values beyond which
the safety of the device cannot be guaranteed. The device should not be
operated at these limits. The parametric values defined in the Electrical
Characteristics tables are not guaranteed at the absolute maximum ratings.
The “Recommended Operating Conditions” table will define the conditions
for actual device operation.
Recommended Operating Conditions
Symbol
Parameter
Min
VCC
VIH
VIL
IOH
IOL
fCLK
tSETUP
Supply Voltage
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Current
LOW Level Output Current
Clock Frequency
Setup Time
Data; A, B, C, D
En P, En T
4.5
2
0
15(Note 2)
DM74ALS161B 15(Note 2)
DM74ALS162B
15(Note 2)
DM74ALS163B
Load
15(Note 2)
Clear (Only for
LOW
DM74ALS162B and
DM74ALS163B)
HIGH
15(Note 2)
12(Note 2)
tHOLD
Setup 1 (Only for 161B)
Hold Time
Clear Inactive
Data; A, B, C, D
En P, En T
10
0(Note 2)
0(Note 2)
Load
0(Note 2)
Clear (Only for DM74ALS162B and
DM74ALS163B
0(Note 2)
Hold 0 (Only for 161B) Clear
0
tW Width of Clock
or Clear Pulse
CLK HIGH or LOW
DM74ALS161B CLR LOW
12.5
15
Width of Load Pulse
15
TA Operating Free Air Temperature
Note 2: The symbol () indicates that the rising edge of the clock is used as a reference.
0
Nom
5
4
3
3
4
7
4
Max
5.5
0.8
0.4
8
40
70
Units
V
V
V
mA
mA
MHz
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
°C
www.fairchildsemi.com
6

6 Page







SeitenGesamt 9 Seiten
PDF Download[ DM74ALS162B Schematic.PDF ]

Link teilen




Besondere Datenblatt

TeilenummerBeschreibungHersteller
DM74ALS1620Octal Tri-State Bus TransceiversNational
National
DM74ALS162BSynchronous Four-Bit CounterFairchild Semiconductor
Fairchild Semiconductor

TeilenummerBeschreibungHersteller
CD40175BC

Hex D-Type Flip-Flop / Quad D-Type Flip-Flop.

Fairchild Semiconductor
Fairchild Semiconductor
KTD1146

EPITAXIAL PLANAR NPN TRANSISTOR.

KEC
KEC


www.Datenblatt-PDF.com       |      2020       |      Kontakt     |      Suche