74ACT257
QUAD 2 CHANNEL MULTIPLEXER (3-STATE)
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HIGH SPEED: tPD = 5 ns (TYP.) at VCC = 5VLOW POWER DISSIPATION:ICC = 4 µA(MAX.) at TA=25°C
COMPATIBLE WITH TTL OUTPUTSVIH = 2V (MIN.), VIL = 0.8V (MAX.)50Ω TRANSMISSION LINE DRIVING CAPABILITY
SYMMETRICAL OUTPUT IMPEDANCE:|IOH| = IOL = 24mA (MIN)
BALANCED PROPAGATION DELAYS:tPLH ≅ tPHL
OPERATING VOLTAGE RANGE:VCC (OPR) = 4.5V to 5.5V
PIN AND FUNCTION COMPATIBLE WITH 74 SERIES 257
IMPROVED LATCH-UP IMMUNITY
DIPSOPTSSOPORDER CODES
PACKAGEDIPSOPTSSOP
TUBE74ACT257B74ACT257M
T & R74ACT257MTR74ACT257TTR
DESCRIPTION
The 74ACT257 is an advanced high-speed CMOSQUAD 2-CHANNEL MULTIPLEXER (3-STATE)fabricated with sub-micron silicon gate anddouble-layer metal wiring C2MOS tecnology.
It is composed of an independent 2-channelmultiplexer with common SELECT and ENABLE(OE)inputs. It is a non-inverting multiplexer. Whenthe ENABLE input is held HIGH, the outputs areforced to a high impedance state. When the
SELECT input is held LOW, \"A\" data is selected;when SELECT input is held HIGH, \"B\" data isselected.
The device is designed to interface directly HighSpeed CMOS systems with TTL, NMOS andCMOS output voltage levels.
All inputs and outputs are equipped withprotection circuits against static discharge, givingthem 2KV ESD immunity and transient excessvoltage.
PIN CONNECTION AND IEC LOGIC SYMBOLS
April 20011/11
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74ACT257
INPUT AND OUTPUT EQUIVALENT CIRCUIT
PIN DESCRIPTION
PIN No12, 5, 11, 143, 6, 10, 134, 7, 9, 12
15
816
SYMBOLSELECT1A to 4A1B to 4B1Y to 4YOEGNDVCC
NAME AND FUNCTIONCommon Data Select Inputs
Data Inputs From Source A
Data Inputs From Source B
Multiplexer Outputs3 State Output Enable Inputs (Active LOW)Ground (0V)
Positive Supply Voltage
TRUTH TABLE
INPUTS
OEHLLLL
X : Don’t Care
Z : High Impedance
OUTPUT
AXLHXX
BXXXLH
YZLHLH
SELECT
XLLHH
LOGIC DIAGRAM
This logic diagram has not be used to estimate propagation delays2/11
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74ACT257
ABSOLUTE MAXIMUM RATINGS
SymbolVCCVIVOIIKIOKIOTstgTL
Supply VoltageDC Input VoltageDC Output VoltageDC Input Diode CurrentDC Output Diode CurrentDC Output CurrentStorage TemperatureLead Temperature (10 sec)
Parameter
Value-0.5 to +7-0.5 to VCC + 0.5-0.5 to VCC + 0.5
± 20± 20± 50± 200-65 to +150
300
UnitVVVmAmAmAmA°C°C
ICC or IGNDDC VCC or Ground Current
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied.
RECOMMENDED OPERATING CONDITIONS
SymbolVCCVIVOTopdt/dv
Supply VoltageInput VoltageOutput VoltageOperating Temperature
Input Rise and Fall Time VCC = 4.5 to 5.5V (note 1)
Parameter
Value4.5 to 5.50 to VCC0 to VCC-55 to 125
8
UnitVVV°Cns/V
1) VIN from 0.8V to 2.0V
3/11
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74ACT257
DC SPECIFICATIONS
Test Condition
Symbol
Parameter
VCC(V)4.55.54.55.54.55.54.55.5
VOL
Low Level Output Voltage
4.55.54.55.5
IIIOZICCTICCIOLDIOHD
Input Leakage Cur-rent
High Impedance Output Leakege Current
Max ICC/InputQuiescent Supply Current
Dynamic Output Current (note 1, 2)
5.55.55.55.55.5
VO = 0.1 V or VCC-0.1VVO = 0.1 V or VCC-0.1VIO=-50 µAIO=-50 µAIO=-24 mAIO=-24 mAIO=50 µAIO=50 µAIO=24 mAIO=24 mAVI = VCC or GNDVI = VIH or VIL VO = VCC or GNDVI = VCC - 2.1VVI = VCC or GNDVOLD = 1.65 V maxVOHD = 3.85 V min
0.6
4
4.45.43.864.86
0.0010.001
0.10.10.360.36± 0.1± 0.5
TA = 25°CMin.2.02.0
Typ.1.51.51.51.54.495.49
0.80.8
4.45.43.764.76
0.10.10.440.44± 1± 51.54075-75
Max.
Value-40 to 85°CMin.2.02.0
0.80.8
4.45.43.74.7
0.10.10.50.5± 1± 51.68050-50
µAmAmAµAmAmAV
Max.
-55 to 125°CMin.2.02.0
0.80.8
V
Max.
VUnit
VIHVILVOH
High Level Input Voltage
Low Level Input Voltage
High Level Output Voltage
1) Maximum test duration 2ms, one output loaded at time2) Incident wave switching is guaranteed on trasmission lines with impedances as low as 50Ω
AC ELECTRICAL CHARACTERISTICS (CL = 50 pF, RL = 500 Ω, Input tr = tf = 3ns)
Test Condition
Symbol
Parameter
VCC(V)5.0(*)5.0(*)5.0(*)5.0(*)
TA = 25°CMin.
Typ.5.06.05.06.0
Max.8.09.08.09.0
Value-40 to 85°CMin.
Max.9.010.09.010.0
-55 to 125°CMin.
Max.9.010.09.010.0
nsnsnsnsUnit
tPLH tPHLPropagation Delay
Time A, B to Y
tPLH tPHLPropagation Delay
Time SELECT to Y
tPZL tPZHOutput Enable
Time
tPLZ tPHZOutput Disable
Time
(*) Voltage range is 5.0V ± 0.5V
4/11
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74ACT257
CAPACITIVE CHARACTERISTICS
Test Condition
Symbol
Parameter
VCC(V)5.05.05.0
fIN = 10MHz
TA = 25°CMin.
Typ.5825
Max.
Value-40 to 85°CMin.
Max.
-55 to 125°CMin.
Max.
pFpFpFUnit
CINCOUTCPD
Input CapacitanceOutput
Capacitance
Power Dissipation Capacitance (note 1)
1) CPD is defined as the value of the IC’s internal equivalent capacitance which is calculated from the operating current consumption without load. (Refer to Test Circuit). Average operating current can be obtained by the following equation. ICC(opr) = CPD x VCC x fIN + ICC/n (per circuit)
TEST CIRCUIT
TEST
tPLH, tPHL
SWITCH
Open2VCCOpen
tPZL, tPLZtPZH, tPHZ
CL = 50pF or equivalent (includes jig and probe capacitance)RL = R1 = 500Ω or equivalent
RT = ZOUT of pulse generator (typically 50Ω)
5/11
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74ACT257
WAVEFORM 1: PROPAGATION DELAYS FOR INVERTING CONDITIONS (f=1MHz; 50% duty cycle)
WAVEFORM 2: PROPAGATION DELAYS FOR NON-INVERTING CONDITIONS (f=1MHz; 50% duty cycle)
6/11
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74ACT257
WAVEFORM 3: OUTPUT ENABLE AND DISABLE TIME (f=1MHz; 50% duty cycle)
7/11
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74ACT257Plastic DIP-16 (0.25) MECHANICAL DATAmmMIN.a1Bbb1DEee3FILZ3.31.278.52.5417.787.15.10.1300.0500.510.770.50.25200.3350.1000.7000.2800.2011.65TYP.MAX.MIN.0.0200.0300.0200.0100.7870.065inchTYP.MAX.DIM.P001C8/11元器件交易网www.cecb2b.com
74ACT257SO-16 MECHANICAL DATADIM.MIN.Aa1a2bb1C0.350.190.50.1mmTYP.MAX.1.750.21.650.460.250.0130.0070.0190.004MIN.inchTYP.MAX.0.0680.0070.0640.0180.010c1 45 (typ.)D9.8100.385Eee3FGLMS3.84.60.55.81.278.894.05.31.270.628(max.)0.1490.1810.0196.20.2280.0500.3500.3930.2440.1570.2080.0500.024P013H9/11元器件交易网www.cecb2b.com
74ACT257TSSOP16 MECHANICAL DATAmmMIN.AA1A2bcDEE1eKL0o0.500.050.850.190.094.96.254.356.44.40.65 BSC4o0.608o0.700o0.0200.100.9TYP.MAX.1.10.150.950.300.205.16.54.480.0020.3350.00750.00350.1930.2460.1690.1970.2520.1730.0256 BSC4o0.0248o0.0280.0040.354MIN.inchTYP.MAX.0.4330.0060.3740.01180.00790.2010.2560.176DIM.AA2A1beKcLEDE1PIN 1 IDENTIFICATION110/11元器件交易网www.cecb2b.com
74ACT257
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