sn74161a ETC-unknow, sn74161a Datasheet

sn74161a

Manufacturer Part Number

sn74161a

Description

Synchronous 4-bit Binary Counters

Manufacturer

ETC-unknow

Datasheet

1.SN74161A.pdf (12 pages)

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C 1995 National Semiconductor Corporation

54LS161A DM54LS161A DM74LS161A

54LS163A DM54LS163A DM74LS163A

Synchronous 4-Bit Binary Counters

General Description

These synchronous presettable counters feature an inter-

nal carry look-ahead for application in high-speed counting

designs The LS161A and LS163A are 4-bit binary counters

The carry output is decoded by means of a NOR gate thus

preventing spikes during the normal counting mode of oper-

ation Synchronous operation is provided by having all flip-

flops clocked simultaneously so that the outputs change co-

incident with each other when so instructed by the count-

enable inputs and internal gating This mode of operation

eliminates the output 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 the setup data after

the next clock pulse regardless of the levels of the enable

input The clear function for the LS161A is asynchronous

and a low level at the clear input sets all four of the flip-flop

outputs low regardless of the levels of clock load or en-

able inputs The clear function for the LS163A is synchro-

nous and a low level at the clear inputs sets all four of the

flip-flop outputs low after the next clock pulse regardless of

the levels of the enable inputs This synchronous clear al-

lows the count length to be modified easily as decoding the

maximum count desired can be accomplished with one ex-

ternal NAND gate The gate output is connected to the clear

input to synchronously clear the counter to all low outputs

The carry look-ahead circuitry provides for cascading coun-

ters for n-bit synchronous applications without additional

Connection Diagram

Dual-In-Line Package

TL F 6397

TL F 6397 – 1

gating Instrumental in accomplishing this function are two

count-enable inputs and a ripple carry output

Both count-enable inputs (P and T) must be high to count

and input T is fed forward to enable the ripple carry output

The ripple carry output thus enabled will produce a high-lev-

el output pulse with a duration approximately equal to the

high-level portion of the Q

ripple carry pulse can be used to enable successive cascad-

ed stages High-to-low level transitions at the enable P or T

inputs may occur regardless of the logic level of the clock

These counters feature a fully independent clock circuit

Changes made to control inputs (enable P or T or load) that

will modify the operating mode have no effect until clocking

occurs The function of the counter (whether enabled dis-

abled loading or counting) will be dictated solely by the

conditions meeting the stable set-up and hold times

Features

54LS161ALMQB 54LS163ADMQB 54LS163AFMQB

Synchronously programmable

Internal look-ahead for fast counting

Carry output for n-bit cascading

Synchronous counting

Load control line

Diode-clamped inputs

Typical propagation time clock to Q output 14 ns

Typical clock frequency 32 MHz

Typical power dissipation 93 mW

Alternate

54LS163) is available Contact a National Semiconduc-

tor Sales Office Distributor for specificaitons

Order Numbers 54LS161ADMQB 54LS161AFMQB

DM74LS161AN DM74LS163AM or DM74LS163AN

54LS163ALMQB DM54LS161AJ DM54LS161AW

DM54LS163AJ DM54LS163AW DM74LS161AM

See NS Package Number E20A J16A

Military Aerospace

M16A N16E or W16A

output This high-level overflow

device

RRD-B30M105 Printed in U S A

(54LS161

May 1992

Related parts for sn74161a

sn74161a Summary of contents

Page 1

DM54LS161A DM74LS161A 54LS163A DM54LS163A DM74LS163A Synchronous 4-Bit Binary Counters General Description These synchronous presettable counters feature an inter- nal carry look-ahead for application in high-speed counting designs The LS161A and LS163A are 4-bit binary counters The carry output is ...

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 DM54LS and 54LS b DM74LS Storage Temperature Range b ...

Page 3

Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted) Symbol Parameter V Input Clamp Voltage High Level Output Voltage Low Level Output Voltage ...

Page 4

Switching Characteristics and (See Section 1 for Test Waveforms and Output Load) (Continued Symbol Parameter t Propagation Delay Time PLH Low to High Level Output t Propagation Delay Time ...

Page 5

Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted) Symbol Parameter V Input Clamp Voltage High Level Output Voltage Low Level Output ...

Page 6

Switching Characteristics and (See Section 1 for Test Waveforms and Output Load) (Continued Symbol Parameter t Propagation Delay Time PLH Low to High Level Output t Propagation Delay Time ...

Page 7

Parameter Measurement Information Note A The input pulses are supplied by generators having the following characteristics PRR Vary PRR to measure f MAX Note B Outputs Q and carry are tested at t where Note ...

Page 8

Timing Diagram LS161A LS163A Synchronous Binary Counters Typical Clear Preset Count and Inhibit Sequences Sequence (1) Clear outputs to zero (2) Preset to binary twelve (3) Count to thirteen fourteen fifteen zero one and two (4) Inhibit ...

Page 9

9 ...

Page 10

Physical Dimensions inches (millimeters) Ceramic Leadless Chip Carrier Package (E) Order Numbers 54LS161ALMQB or 54LS163ALMQB 16-Lead Ceramic Dual-In-Line Package (J) Order Numbers 54LS161ADMQB 54LS163ADMQB DM54LS161AJ or DM54LS163AJ NS Package Number E20A NS Package Number J16A 10 ...

Page 11

Physical Dimensions inches (millimeters) (Continued) 16-Lead Small Outline Molded Package (M) Order Number DM74LS161AM or DM74LS163AM 16-Lead Molded Dual-In-Line Package (N) Order Numbers DM74LS161AN DM74LS163AN NS Package Number M16A NS Package Number N16E 11 ...

Page 12

Physical Dimensions inches (millimeters) (Continued) 16-Lead Ceramic Flat Package (W) Order Numbers 54LS161AFMQB 54LS163AFMQB LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE ...

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