SGS Thomson Microelectronics 74ACT257 Datasheet
74ACT257
QUAD 2 CHANNEL MULTIPLEXER (3-STATE)
■ HIGH SPEED: t
■ LOW POWE RDISSIPATION:
=8 µA (MAX.)at TA=25oC
I
CC
■ COMPATIBLEWITHTTL OUTPUTS
V
=2V(MIN),VIL= 0.8V(MAX)
IH
■ 50Ω TRANSMISSIONLINEDRIVING
=5ns(TYP.)at VCC=5V
PD
CAPABILITY
■ SYMMETRICALOUTPUTIMPEDANCE:
|I
|=IOL=24mA(MIN)
OH
■ BALANCEDPROPAGATIONDELAYS:
t
≅ t
PLH
PHL
■ OPERATINGVOLTAGE RANGE:
V
(OPR)= 4.5Vto 5.5V
CC
■ PINAND FUNCTION COMPATIBLE WITH
74 SERIES257
■ IMPROVED LATCH-UP IMMUNITY
DESCRIPTION
The ACT257 is an advanced high-speed CMOS
QUAD 2 CHANNEL MULTIPLEXER (3-STATE)
fabricated with sub-micron silicon gate and
double-layermetal wiring C
2
MOS technology.
It is ideal for low power applications mantaining
high speed operation similar to equivalentBipolar
SchottkyTTL.
These IC’s are composed of an independent 2
channel multiplexer with common SELECT and
B
(Plastic Package)
(Micro Package)
M
ORDERCODES :
74ACT257B 74ACT257M
ENABLEINPUT.
TheAC257 is a noninverting multiplexer.
When the ENABLE INPUT is held ”High” outputs
of both IC’s become high impedance state. If
SELECT INPUT is held ”Low”, ”A” data is
selected, when SELECT INPUT is ”High”, ”B”
datais closen.
The device is designed to interface directly High
Speed CMOS systems with TTL, NMOS and
CMOSoutput voltage levels.
All inputs and outputs are equipped with
protectioncircuits against static discharge, giving
them 2KV ESD immunity and transient excess
voltage.
PINCONNECTION AND IEC LOGIC SYMBOLS
April 1997
1/10
74ACT257
INPUTAND OUTPUTEQUIVALENTCIRCUIT
TRUTH TABLE
INPUTS OUTPUTS
OESELECTABY
HXXXZ
LLLXL
LLHXH
LHXLL
LHXHH
X = DON’T CARE Z =HIGH IMPEDANCE
PIN DESCRIPTION
PI N No SYM B O L NAME A ND FUNCTI ON
1 SELECT Common Data Select Input
2, 5, 14, 11 1A to 4A Data Input From Source A
3, 6, 13, 10 1B to 4B Data Inputs from Source B
4, 7, 12, 9 1Y to 4Y 3 State Multiplexer Outputs
15 OE 3 State Output Enable
Inputs (Active LOW)
8 GND Ground (0V)
16 V
CC
Positive Supply Voltage
LOGICDIAGRAMS
This logic diagram has not be used to estimate propagation delays
2/10
74ACT257
ABSOLUTE MAXIMUMRATINGS
Symb o l Parame t er Val u e Uni t
V
V
V
I
I
OK
I
orI
I
CC
T
T
Absolute Maximum Ratings are those values beyond which damage to thedevice may occur. Functional operation under these condition is not implied.
RECOMMENDEDOPERATINGCONDITIONS
Symbol Parameter Valu e Unit
V
V
V
T
dt/dv Input Rise and Fall Time V
1) VINfrom0.8Vto2.0V
Supply Voltage -0.5 to +7 V
CC
DC Input Voltage -0.5 to VCC+ 0.5 V
I
DC Output Voltage -0.5 to VCC+ 0.5 V
O
DC Input Diode Current ± 20 mA
IK
DC Output Diode Current ± 20 mA
DC Output Current ± 50 mA
O
DC VCCor Ground Current ± 200 mA
GND
Storage Temperature -65 to +150
stg
Lead Temperature (10 sec) 300
L
Supply Voltage 4.5 to 5.5 V
CC
Input Voltage 0 to V
I
Output Voltage 0 to V
O
Operating Temperature: -40 to +85
op
= 4.5 to 5.5V (note 1) 8 ns/V
CC
CC
CC
o
C
o
C
V
V
o
C
3/10
Loading...