SGS Thomson Microelectronics 74VHC238 Datasheet

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74VHC238

3 TO 8 LINEDECODER

■ HIGHSPEED:t

■ LOW POWER DISSIPATION:

=4 µA (MAX.)at TA=25oC

I

CC

■ HIGHNOISEIMMUNITY:

V

NIH=VNIL

■ POWERDOWNPROTECTIONON INPUTS

■ SYMMETRICALOUTPUTIMPEDANCE:

|=IOL=8 mA(MIN)

|I

OH

■ BALANCEDPROPAGATIONDELAYS:

t

≅ t

PLH

■ OPERATINGVOLTAGERANGE:

V

(OPR)= 2Vto 5.5V

CC

■ PINANDFUNCTIONCOMPATIBLEWITH

=28%VCC(MIN.)

PHL

=5.5ns (TYP.)at VCC=5V

PD

74SERIES238

■ IMPROVEDLATCH-UPIMMUNITY

DESCRIPTION

The 74VHC238 is an advanced high-speed
CMOS 3 TO 8 LINE DECODER fabricated with
sub-micron silicon gate and double-layer metal
wiringC

2

MOStechnology.

If the device is enabled, 3 binary select inputs (A,
B and C) determine which one of the outputs will
go high. If enable input G1 is held low or either

M1

(Micro Package)

(TSSOPPackage)

T

ORDERCODES :

74VHC238M 74VHC238T

G2A or G2B is held high, decoding function is
inhibitedand all the 8 outputsgo to low.

Three enable inputs are provided to ease
cascade connection and application of this
addressdecoders for memory systems.

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 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

June 1999

1/8

74VHC238

INPUT EQUIVALENTCIRCUIT

PIN DESCRIPTION

PI N No SYM BO L NAM E AND FUNCT I O N

1, 2, 3 A, B, C Address Inputs

4, 5 G2A, G2B Enable Inputs

6 G1 Enable Input

15, 14, 13,
12, 11, 10,

9, 7

8 GND Ground (0V)

16 V

Y0 to Y7 Outputs

CC

Positive Supply Voltage

TRUTH TABLE

INPUTS OUTPUTS

ENABLE SELECT

G2BG2AG1 C B A Y0Y1Y2Y3Y4Y5Y6Y7

XXLXXXLLLLLLLL
XHXXXXLLLLLLLL
HXXXXXLLLLLLLL
LLHLLLHLLLLLLL
LLHLLHLHLLLLLL
LLHLHLLLHLLLLL
LLHLHHLLLHLLLL
LLHHLLLLLLHLLL
LLHHLHLLLLLHLL
LLHHHLLLLLLLHL
LLHHHHLLLLLLLH

X:Don’tCare

LOGICDIAGRAM

Thislogic diagram has notbe used to estimate propagation delays

2/8

74VHC238

ABSOLUTE MAXIMUM RATINGS

Symb o l Para met er Val u e Uni t

V

V

V

I

I

OK

I

or I

I

CC

T

T

AbsoluteMaximumRatingsarethosevaluesbeyondwhichdamageto thedevicemayoccur.Functionaloperation underthesecondition isnotimplied.

RECOMMENDED OPERATING CONDITIONS

Symb o l Para met er Value Un it

V

V

V

T

dt/dv

1)VINfrom30%to70%of V

Supply Voltage -0.5 to +7.0 V

CC

DC Input Voltage -0.5 to +7.0 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

O

DC VCCor Ground Current

GND

Storage Temperature -65 to +150

stg

Lead Temperature (10 sec) 300

L

Supply Voltage 2.0 to 5.5 V

CC

Input Voltage 0 to 5.5 V

I

Output Voltage 0 to V

O

Operating Temperature -40 to +85

op

(V

CC
CC

=3.3±0.3V)
=5.0±0.5V)

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

CC

25 mA

±

75 mA

±

CC

0 to 100

0to20

o

C

o

C

V

o

C

ns/V
ns/V

DC SPECIFICATIONS

Symb o l Para met er Test C o n dit io ns Val u e Uni t

=25oC -40 to 85oC

V

CC

(V)

High Level Input

V

IH

Voltage

V

Low Level Input

IL

Voltage

V

High Level Output

OH

Voltage

Low Level Output

V

OL

Voltage

Input Leakage Current 0 to 5.5 VI= 5.5V or GND ±0.1 ±1.0 µA

I

I

Quiescent Supply

I

CC

2.0 1.5 1.5

3.0 to 5.5 0.7V

2.0 0.5 0.5

3.0 to 5.5 0.3V

2.0 IO=-50 µA 1.9 2.0 1.9

3.0 I

4.5 I

3.0 I

4.5 I

=-50 µA 2.9 3.0 2.9

O

=-50µA 4.4 4.5 4.4

O

=-4 mA 2.58 2.48

O

=-8 mA 3.94 3.8

O

2.0 IO=50 µA 0.0 0.1 0.1

3.0 I

4.5 I

3.0 I

4.5 I

=50 µA 0.0 0.1 0.1

O

=50µA 0.0 0.1 0.1

O

=4 mA 0.36 0.44

O

=8 mA 0.36 0.44

O

5.5 VI=VCCorGND 4 40 µA

Current

T

A

Min. Typ. Max. Min. Max.

CC

0.7V

CC

0.3V

CC

CC

V

V

V

V

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