参数资料
型号: SN74AS161D
厂商: TEXAS INSTRUMENTS INC
元件分类: 计数器
英文描述: AS SERIES, SYN POSITIVE EDGE TRIGGERED 4-BIT UP BINARY COUNTER, PDSO16
封装: GREEN, PLASTIC, MS-012AC, SOIC-16
文件页数: 1/26页
文件大小: 900K
代理商: SN74AS161D
SN54ALS161B, SN54ALS162B, SN54ALS163B, SN54AS161, SN54AS163
SN74ALS161B, SN74ALS163B, SN74AS161, SN74AS163
SYNCHRONOUS 4-BIT DECADE AND BINARY COUNTERS
SDAS276A – DECEMBER 1994 – REVISED JULY 2000
1
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
D Internal Look-Ahead Circuitry for Fast
Counting
D Carry Output for n-Bit Cascading
D Synchronous Counting
D Synchronously Programmable
D Package Options Include Plastic
Small-Outline (D) and Shrink Small-Outline
(DB) Packages, Ceramic Chip Carriers (FK),
Standard Plastic (N) and Ceramic (J) DIPs
description
These synchronous, presettable, 4-bit decade
and binary counters feature an internal carry
look-ahead circuitry for application in high-speed
counting designs. The SN54ALS162B is a 4-bit
decade counter. The ’ALS161B, ’ALS163B,
’AS161, and ’AS163 devices are 4-bit binary
counters. Synchronous operation is provided by
having all flip-flops clocked simultaneously so that
the outputs change coincidentally with each other
when instructed by the count-enable (ENP, ENT)
inputs and internal gating. This mode of operation
eliminates the output counting spikes normally
associated
with
asynchronous
(ripple-clock)
counters. A buffered clock (CLK) input triggers the
four flip-flops on the rising (positive-going) edge of
the clock input waveform.
These counters are fully programmable; they can
be preset to any number between 0 and 9 or 15.
Because presetting is synchronous, setting up a
low level at the load (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 inputs.
The clear function for the ’ALS161B and ’AS161 devices is asynchronous. A low level at the clear (CLR) input
sets all four of the flip-flop outputs low, regardless of the levels of the CLK, LOAD, or enable inputs. The clear
function for the SN54ALS162B, ’ALS163B, and ’AS163 devices is synchronous, and a low level at CLR 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 allows the count length to be modified easily by decoding the Q outputs for the maximum
count desired. The active-low output of the gate used for decoding is connected to CLR to synchronously clear
the counter to 0000 ( LLLL ).
The carry look-ahead circuitry provides for cascading counters for n-bit synchronous applications without
additional gating. ENP and ENT inputs and a ripple-carry (RCO) output are instrumental in accomplishing this
function. Both ENP and ENT must be high to count, and ENT is fed forward to enable RCO. RCO, thus enabled,
Copyright
2000, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
On products compliant to MIL-PRF-38535, all parameters are tested
unless otherwise noted. On all other products, production
processing does not necessarily include testing of all parameters.
SN54ALS161B, SN54ALS162B, SN54ALS163B,
SN54AS161, SN54AS163 ...J PACKAGE
SN74ALS161B, SN74AS161,
SN74AS163 ...D OR N PACKAGE
SN74ALS163B . . . D, DB, OR N PACKAGE
(TOP VIEW)
32
1 20 19
910 11 12 13
4
5
6
7
8
18
17
16
15
14
QA
QB
NC
QC
QD
A
B
NC
C
D
SN54ALS161B, SN54ALS162B, SN54ALS163B,
SN54AS161, SN54AS163 . . . FK PACKAGE
(TOP VIEW)
CLK
CLR
NC
LOAD
ENT
RCO
ENP
GND
NC
NC – No internal connection
V
CC
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
CLR
CLK
A
B
C
D
ENP
GND
VCC
RCO
QA
QB
QC
QD
ENT
LOAD
相关PDF资料
PDF描述
SN74AS163NSR AS SERIES, SYN POSITIVE EDGE TRIGGERED 4-BIT UP BINARY COUNTER, PDSO16
SN74AS162D AS SERIES, SYN POSITIVE EDGE TRIGGERED 4-BIT UP DECADE COUNTER, PDSO16
SN74ALS162BD ALS SERIES, SYN POSITIVE EDGE TRIGGERED 4-BIT UP DECADE COUNTER, PDSO16
SN74AS163DE4 AS SERIES, SYN POSITIVE EDGE TRIGGERED 4-BIT UP BINARY COUNTER, PDSO16
SN74AS163DR AS SERIES, SYN POSITIVE EDGE TRIGGERED 4-BIT UP BINARY COUNTER, PDSO16
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SN74AS161DRE4 功能描述:计数器 IC Synchronous 4-Bit Binary Counters RoHS:否 制造商:NXP Semiconductors 计数器类型:Binary Counters 逻辑系列:74LV 位数:10 计数法: 计数顺序: 工作电源电压:1 V to 5.5 V 工作温度范围:- 40 C to + 125 C 封装 / 箱体:SOT-109 封装:Reel
SN74AS161DRG4 功能描述:计数器 IC Synch 4B Binary Counters RoHS:否 制造商:NXP Semiconductors 计数器类型:Binary Counters 逻辑系列:74LV 位数:10 计数法: 计数顺序: 工作电源电压:1 V to 5.5 V 工作温度范围:- 40 C to + 125 C 封装 / 箱体:SOT-109 封装:Reel