74LS257B 반도체 회로 부품 판매점
3-STATE Quad 2-Data Selectors/Multiplexers
|
|
 Fairchild Semiconductor |
June 1989
Revised November 1999
DM74LS257B
3-STATE Quad 2-Data Selectors/Multiplexers
General Description
These Schottky-clamped high-performance multiplexers
feature 3-STATE outputs that can interface directly with
data lines of bus-organized systems. With all but one of the
common outputs disabled (at a high impedance state), the
low impedance of the single enabled output will drive the
bus line to a HIGH or LOW logic level. To minimize the pos-
sibility that two outputs will attempt to take a common bus
to opposite logic levels, the output enable circuitry is
designed such that the output disable times are shorter
than the output enable times.
This 3-STATE output feature means that n-bit (paralleled)
data selectors with up to 258 sources can be implemented
for data buses. It also permits the use of standard TTL reg-
isters for data retention throughout the system.
Features
s 3-STATE versions LS157 and LS158 with same pinouts
s Schottky-clamped for significant improvement in A-C
performance
s Provides bus interface from multiple sources in
high-performance systems
s Average propagation delay from data input 12 ns
s Typical power dissipation: 50 mW
Ordering Code:
Order Number Package Number
Package Description
DM74LS257BM
M16A
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
DM74LS257BN
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.
Connection Diagram
Logic Diagram
Function Table
Output
Control
H
L
L
L
L
H = HIGH Level
L = LOW Level
Inputs
Select A
B
X XX
L LX
L HX
H XL
H XH
X = Don’t Care
Z = High Impedance (off)
Output Y
LS257
Z
L
H
L
H
© 1999 Fairchild Semiconductor Corporation DS006417
www.fairchildsemi.com
Absolute Maximum Ratings(Note 1)
Supply Voltage
7V
Input Voltage
7V
Operating Free Air Temperature Range 0°C to +70°C
Storage Temperature Range
−65°C to +150°C
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
VCC
VIH
VIL
IOH
IOL
TA
Parameter
Supply Voltage
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Current
LOW Level Output Current
Free Air Operating Temperature
DC Electrical Characteristics
Min
4.75
2
0
Nom
5
Max
5.25
0.8
−2.6
24
70
Symbol
Parameter
Conditions
Typ
Min
(Note 2)
VI Input Clamp Voltage
VCC = Min, II = −18 mA
VOH HIGH Level Output Voltage
VIL = Max, VIH = Min
2.4 3.1
VOL LOW Level Output
VIL = Max, VIH = Min
0.35
Voltage
IOL = 12 mA, VCC = Min
0.25
II Input Current @ Max
VCC = Max,
Select
Input Voltage
VI = 7V
Other
IIH HIGH Level Input
VCC = Max,
Select
Current
VI = 2.7V
Other
IIL LOW Level Input
VCC = Max,
Select
Current
VI = 0.4V
Other
IOZH
OFF-State Output Current with
VCC = Max, VO = 2.7V
HIGH Level Output Voltage Applied VIH = Min, VIL = Max
IOZL
OFF-State Output Current with
VCC = Max, VO = 0.4V
LOW Level Output Voltage Applied VIH = Min, VIL = Max
IOS Short Circuit Output Current
VCC = Max (Note 3)
−20
ICCH
Supply Current with Outputs HIGH VCC = Max (Note 4)
5.9
ICCL
Supply Current with Outputs LOW VCC = Max (Note 4)
9.2
ICCZ
Supply Current with Outputs Disabled VCC = Max (Note 4)
12
Note 2: All typicals are at VCC = 5V, TA = 25°C.
Note 3: Not more than one output should be shorted at a time, and the duration should not exceed one second.
Note 4: ICC is measured with all outputs open and all possible inputs grounded, while achieving the stated output conditions.
Max
−1.5
0.5
0.4
0.2
0.1
40
20
−0.8
−0.4
20
−20
−100
10
16
19
Units
V
V
V
mA
mA
°C
Units
V
V
V
mA
µA
mA
µA
µA
mA
mA
mA
mA
www.fairchildsemi.com
2
|
PDF 파일 내의 페이지 : 총 5 페이지
제조업체: Fairchild Semiconductor
( fairchild )
74LS257B multiplexer
데이터시트 다운로드 :
[ 74LS257B.PDF ]
[ 74LS257B 다른 제조사 검색 ]
국내 전력반도체 판매점
상호 : 아이지 인터내셔날
전화번호 : 051-319-2877
[ 홈페이지 ]
IGBT, TR 모듈, SCR, 다이오드모듈, 각종 전력 휴즈
( IYXS, Powerex, Toshiba, Fuji, Bussmann, Eaton )
전력반도체 문의 : 010-3582-2743
관련 데이터시트
74LS257
LOW POWER SCHOTTKY - ON Semiconductor
74LS257
3-STATE Quad 2-Data Selectors/Multiplexers - Fairchild Semiconductor
74LS257
Quadruple 2-line-to-1-line Data Selectors/Multiplexers(with non inverted 3-state outputs) - Hitachi Semiconductor
74LS257
TRI-STATE Quad 2-Data Selectors/Multiplexers - National Semiconductor
74LS257B
3-STATE Quad 2-Data Selectors/Multiplexers - Fairchild Semiconductor
74LS257B
QUAD 2-INPUT MULTIPLEXER - Motorola Semiconductors