Page 1
QUAD 2 CHANNEL MULTIPLEXER (3-STATE)
■ HIGHSPEED:t
■ LOWPOWER DISSIPATION :
=4µA (MAX.)at TA=25oC
I
CC
■ COMPATIBLEWITHTTL OUTPUTS:
=2V(MIN),VIL=0.8V(MAX)
V
IH
■ POWERDOWNPROTECTIONON INPUTS&
OUTPUTS
■ SYMMETRICALOUTPUTIMPEDANCE:
|I
|=IOL=8mA(MIN)
OH
■ BALANCEDPROPAGATIONDELAYS:
t
PLH≅tPHL
■ OPERATINGVOLTAGERANGE:
(OPR)= 4.5Vto5.5V
V
CC
■ PINANDFUNCTIONCOMPATIBLEWITH
74SERIES257
■ IMPROVEDLATCH-UP IMMUNITY
■ LOWNOISE:V
DESCRIPTION
The 74VHCT257A is an advanced high-speed
CMOS QUAD 2 CHANNEL MULTIPLEXER
(3-STATE)fabricatedwithsub-micron silicon gate
and double-layer metal wiring C
technology.
It is composed of four independent 2 channel
multiplexers with common SELECT and ENABLE
INPUT.
=5.8ns(TYP.)atVCC=5V
PD
=0.8V(Max.)
OLP
2
MOS
74VHCT257A
PRELIMINARY DATA
SOP TSSOP
ORDER CODES
PACKAGE TUBE T & R
SOP 74VHCT257AM 74VHCT257AMTR
TSSOP 74VHCT257ATTR
The 74VHCT257A is a non inverting multiplexer.
When the ENABLE INPUT is held ”High”, all
outputs become high impedance state. If
SELECT INPUT is held ”Low”, ”A” data is
selected, when SELECT INPUT is ”High”, ”B”
datais chosen.
Power down protection is provided on all inputs
and output and 0 to 7V can be accepted on
inputs with no regard to the supply voltage. This
devicecan be used to interface 5V to 3V.
All inputs and outputs are equipped with
protection circuits against static discharge, giving
them 2KV ESD immunity and transient excess
voltage.
PIN CONNECTION AND IEC LOGICSYMBOLS
March 2000
1/9
Page 2
74VHCT257A
INPUT EQUIVALENTCIRCUIT
TRUTH TABLE
OE SELECT A B Y
HXXXZ
LLLXL
LLHXH
LHXLL
LHXHH
X= DON’TCARE Z =HIGHIMPEDANCE
PIN DESCRIPTION
PI N No SYM BO L NAM E AND FUNCT I O N
1 SELECT Common Data Select Input
2, 5, 14, 11 1A to 4A Data Inputs 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
Input (Active LOW)
8 GND Ground (0V)
16 V
INPUTS OUTPUTS
CC
Positive Supply Voltage
LOGICDIAGRAM
Thislogicdiagram has not be usedto estimate propagation delays
2/9
Page 3
74VHCT257A
ABSOLUTE MAXIMUM RATINGS
Symb o l Para met er Value U n i t
V
V
V
V
I
I
OK
I
or I
I
CC
T
T
AbsoluteMaximumRatingsarethosevaluesbeyondwhichdamageto thedevicemayoccur. Functionaloperationunderthese condition isnot implied.
1)Outputin OFFState
2)Highor LowState
RECOMMENDED OPERATINGCONDITIONS
Symb o l Para met er Value Unit
V
V
V
V
T
dt/dv
1)Outputin OFFState
2)Highor LowState
from0.8Vto 2V
3)V
IN
Supply Voltage -0.5 to +7.0 V
CC
DC Input Voltage -0.5 to +7.0 V
I
DC Output Voltage (see note 1) -0.5 to +7.0 V
O
DC Output Voltage (see note 2) -0.5 to VCC+ 0.5 V
O
DC Input Diode Current - 20 mA
IK
DC Output Diode Current
DC Output Current
O
DC VCCor Ground Current ± 50 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 5.5 V
I
Output Voltage (see note 1) 0 to 5.5 V
O
Output Voltage (see note 2) 0 to V
O
Operating Temperature -40 to +85
op
Input Rise and Fall Time (see note 3) (V
=5.0±0.5V)
CC
20 mA
±
25 mA
±
CC
0 to 20 ns/V
o
C
o
C
V
o
C
3/9
Page 4
74VHCT257A
DC SPECIFICATIONS
Symb o l Para met er Test Co n diti o ns Val u e Uni t
T
=25oC -40 to 85oC
A
±0.25 ±2.5 µA
1.35 1.5 mA
V
V
V
V
I
I
∆I
I
OPD
V
CC
High Level Input
IH
(V)
4.5 to 5.5 2 2 V
Min. Typ. Max. Min. Max.
Voltage
Low Level Input
IL
4.5 to 5.5 0.8 0.8 V
Voltage
High Level Output
OH
Voltage
Low Level Output
OL
Voltage
High Impedance
OZ
Output Leakage
4.5 IO=-50 µA 4.4 4.5 4.4
4.5 I
=-8 mA 3.94 3.8
O
4.5 IO=50µA 0.0 0.1 0.1
4.5 I
4.5 to 5.5 VI=VIHor V
=8 mA 0.36 0.44
O
IL
VO= 0V to 5.5V
Current
Input Leakage Current 0 to 5.5 VI= 5.5V or GND ±0.1 ±1.0 µA
I
I
Quiescent Supply
CC
5.5 VI=VCCorGND 4 40 µA
Current
Additional Worst Case
CC
Supply Current
5.5 One Input at 3.4V,
other input at V
CC
or
GND
Output Leakage
0V
= 5.5V 0.5 5.0 µA
OUT
Current
V
V
AC ELECTRICALCHARACTERISTICS
(Inputt
r=tf
=3 ns)
Symbol Parameter Test Conditi on Value Unit
t
Propagation Delay
PLH
Time A, B to Y
t
PHL
Propagation Delay
t
PLH
t
Time SELECT to Y
PHL
Output Enable Time 5.0
t
PZL
t
PZH
t
Output Disable Time 5.0
PLZ
t
PHZ
(*) Voltagerangeis5V± 0.5V
V
(V)
5.0
5.0
5.0
5.0
5.0
CC
C
L
(pF)
(*)
15 5.8 9.3 1.0 11.0
(*)
50
(*)
15 7.0 11.0 1.0 13.0
(*)
50
(*)
15 6.7 10.5 1.0 12.5
(*)
50 9.2 14.0 1.0 16.0
(*)
Min. Typ. Max. Min. Max.
50
=25oC -40 to 85oC
T
A
8.3 12.8 1.0 14.5
9.5 14.5 1.0 16.5
8.6 12.0 1.0 13.5
ns
ns
ns
ns
4/9
Page 5
74VHCT257A
CAPACITIVE CHARACTERISTICS
Symb o l Para met er Test Co n diti o ns Val u e Uni t
=25oC -40 to 85oC
T
A
Min. Typ. Max. Min. Max.
Input Capacitance 4 10 10
C
IN
C
Output Capacitance 6
OUT
Power Dissipation
C
PD
23 pF
Capacitance (note 1)
1)CPDisdefinedasthevalue oftheIC’sinternalequivalentcapacitance whichiscalculated fromtheoperatingcurrentconsumption withoutload.(Referto
TestCircuit).Average operatingcurrentcanbeobtained bythefollowingequation.I
(opr)=CPD• VCC• fIN+ICC/4 (per Channel)
CC
DYNAMICSWITCHING CHARACTERISTICS
Symb o l Para met er Test Co n diti o ns Val u e Uni t
T
V
CC
(V)
V
V
V
Dynamic Low Voltage
OLP
Quiet Output (note 1, 2)
OLV
Dynamic High Voltage
IHD
5.0
5.0 2.0
C
L
=50pF
Min. Typ. Max. Min. Max.
Input (note 1, 3)
V
Dynamic Low Voltage
ILD
5.0 0.8
Input (note 1, 3)
1)Worstcasepackage.
2)Maxnumber ofoutputsdefinedas(n).Datainputs aredriven0Vto3.0V,(n -1)outputs switching andone outputat GND.
3)Maxnumber ofdatainputs(n)switching.(n-1)switching0Vto3.0V.Inputsundertestswitching:3.0Vtothreshold (V
=25oC -40 to 85oC
A
0.3 0.8
-0.8 -0.3
),0Vtothreshold (V
ILD
),f=1MHz.
IHD
pF
pF
V
TESTCIRCUIT
TEST SWITCH
t
PLH,tPHL
t
PZL,tPLZ
t
PZH,tPHZ
CL= 15/50 pF orequivalent (includes jig and probe capacitance)
=1KΩ orequivalent
R
L=R1
R
ofpulsegenerator (typically50Ω)
T=ZOUT
Open
V
CC
GND
5/9
Page 6
74VHCT257A
WAVEFORM 1: PROPAGATIONDELAYS FOR INVERTINGCONDITIONS
(f=1MHz;50%duty cycle)
WAVEFORM 2: PROPAGATION DELAYS FOR NON-INVERTING CONDITIONS (f=1MHz; 50% duty
cycle)
6/9
Page 7
74VHCT257A
WAVEFORM 3: OUTPUT ENABLEAND DISABLE TIME
(f=1MHz; 50% duty cycle)
7/9
Page 8
74VHCT257A
SO-16 MECHANICALDATA
DIM.
MIN. TYP. MAX. MIN. TYP. MAX.
A 1.75 0.068
a1 0.1 0.2 0.004 0.007
a2 1.65 0.064
b 0.35 0.46 0.013 0.018
b1 0.19 0.25 0.007 0.010
C 0.5 0.019
c1 45 (typ.)
D 9.8 10 0.385 0.393
E 5.8 6.2 0.228 0.244
e 1.27 0.050
e3 8.89 0.350
F 3.8 4.0 0.149 0.157
G 4.6 5.3 0.181 0.208
L 0.5 1.27 0.019 0.050
M 0.62 0.024
S 8 (max.)
mm inch
8/9
P013H
Page 9
TSSOP16 MECHANICAL DATA
74VHCT257A
DIM.
mm inch
MIN. TYP. MAX. MIN. TYP. MAX.
A 1.1 0.433
A1 0.05 0.10 0.15 0.002 0.004 0.006
A2 0.85 0.9 0.95 0.335 0.354 0.374
b 0.19 0.30 0.0075 0.0118
c 0.09 0.20 0.0035 0.0079
D 4.9 5 5.1 0.193 0.197 0.201
E 6.25 6.4 6.5 0.246 0.252 0.256
E1 4.3 4.4 4.48 0.169 0.173 0.176
e 0.65 BSC 0.0256 BSC
K0
o
o
4
o
8
o
0
o
4
L 0.50 0.60 0.70 0.020 0.024 0.028
o
8
A2
A
A1
PIN 1 IDENTIFICATION
b
e
c
K
L
E
D
E1
1
9/9
Page 10
74VHCT257A
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of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is
granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specification mentioned in this publication are
subject to change without notice. Thispublication supersedes and replaces all informationpreviously supplied. STMicroelectronics products
are not authorized for use as critical components in lifesupport devices or systems withoutexpress written approval of STMicroelectronics.
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