SGS Thomson Microelectronics 74VHC257 Datasheet

74VHC257

QUAD 2 CHANNEL MULTIPLEXER (3-STATE)

June 1999

■ HIGHSPEED :t

PD

=3.7ns (TYP.)atVCC=5V

■ LOWPOWERDISSIPATION:

I

CC

=4µA (MAX.)at TA=25oC

■ HIGHNOISEIMMUNITY:

V

NIH=VNIL

=28%VCC(MIN.)

■ POWERDOWNPROTECTIONON INPUTS

■ SYMMETRICALOUTPUTIMPEDANCE:

|I

OH

|=IOL=8 mA(MIN)

■ BALANCEDPROPAGATIONDELAYS:

t

PLH≅tPHL

■ OPERATINGVOLTAGERANGE:

V

CC

(OPR)=2V to5.5V

■ PINAND FUNCTIONCOMPATIBLEWITH

74SERIES257

■ IMPROVEDLATCH-UP IMMUNITY

■ LOWNOISEV

OLP

=0.8V(Max.)

DESCRIPTION

The 74VHC257 is an advanced high-speed
CMOS QUAD 2 CHANNEL MULTIPLEXER
(3-STATE)fabricated withsub-micron silicon gate
and double-layer metal wiring C

2

MOS

technology.
It is composed of four independent 2 channel

multiplexers with common SELECT and ENABLE
INPUT.

The 74VHC257is 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 0 to 7V can be accepted on inputs with no
regard to the supply voltage. This device can be
used to interface5V 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 ANDIEC LOGIC SYMBOLS

M

(Micro Package)

T

(TSSOPPackage)

ORDERCODES :

74VHC257M 74VHC257T



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INPUT EQUIVALENTCIRCUIT

LOGICDIAGRAM

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 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

TRUTH TABLE

INPUTS OUTPUTS

OE SELECT A B Y

HXXXZ

LLLXL
LLHXH
LHXLL
LHXHH

X= DON’T CARE Z = HIGHIMPEDANCE

Thislogic diagram has notbe used to estimate propagation delays

74VHC257

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ABSOLUTE MAXIMUM RATINGS

Symb o l Para met er Val u e Uni t

V

CC

Supply Voltage -0.5 to +7.0 V

V

I

DC Input Voltage -0.5 to +7.0 V

V

O

DC Output Voltage -0.5 to VCC+ 0.5 V

I

IK

DC Input Diode Current - 20 mA

I

OK

DC Output Diode Current ± 20 mA

I

O

DC Output Current

±

25 mA

I

CC

or I

GND

DC VCCor Ground Current

±

50 mA

T

stg

Storage Temperature -65 to +150

o

C

T

L

Lead Temperature (10 sec) 300

o

C

AbsoluteMaximum Ratingsarethosevaluesbeyondwhichdamageto thedevicemayoccur. Functionaloperationundertheseconditionisnotimplied.

RECOMMENDED OPERATING CONDITIONS

Symb o l Para met er Value Un it

V

CC

Supply Voltage 2.0 to 5.5 V

V

I

Input Voltage 0 to 5.5 V

V

O

Output Voltage 0 to V

CC

V

T

op

Operating Temperature -40 to +85

o

C

dt/dv

Input Rise and Fall Time (see note 1) (V

CC

=3.3±0.3V)

(V

CC

=5.0±0.5V)

0 to 100

0to20

ns/V
ns/V

1)VINfrom30%to70%of V

CC

DC SPECIFICATIONS

Symb o l Para met er Test Co n dit i ons Val u e Uni t

V

CC

(V)

T

A

=25oC -40 to 85oC

Min. Typ. Max. Min. Max.

V

IH

High Level Input
Voltage

2.0 1.5 1.5
V

3.0 to 5.5 0.7V

CC

0.7V

CC

V

IL

Low Level Input
Voltage

2.0 0.5 0.5
V

3.0 to 5.5 0.3V

CC

0.3V

CC

V

OH

High Level Output
Voltage

2.0 IO=-50µA 1.9 2.0 1.9

V

3.0 I

O

=-50µA 2.9 3.0 2.9

4.5 I

O

=-50 µA 4.4 4.5 4.4

3.0 I

O

=-4 mA 2.58 2.48

4.5 I

O

=-8 mA 3.94 3.8

V

OL

Low Level Output
Voltage

2.0 IO=50 µ A 0.0 0.1 0.1

V

3.0 I

O

=50µA 0.0 0.1 0.1

4.5 I

O

=50 µA 0.0 0.1 0.1

3.0 I

O

=4 mA 0.36 0.44

4.5 I

O

=8 mA 0.36 0.44

I

OZ

High Impedance
Output Leakage
Current

5.5

VI=VIHor V

IL

VO=VCCor GND

±0.25 ±2.5 µA

I

I

Input Leakage Current 0 to5.5 VI= 5.5V or GND

±

0.1

±

1.0

µ

A

I

CC

Quiescent Supply
Current

5.5 VI=VCCorGND 4 40

µ

A

74VHC257

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