SGS Thomson Microelectronics 74VHCT257A Datasheet



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

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

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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

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