SGS Thomson Microelectronics 74VHCT245A Datasheet



■ HIGHSPEED:t

■ LOW POWER DISSIPATION:

=4 µA (MAX.)at TA=25oC

I

CC

■ COMPATIBLEWITHTTLOUTPUTS:

=2V(MIN),VIL=0.8V(MAX)

V

IH

■ POWERDOWNPROTECTIONON INPUTS&

=4.5ns(TYP.)atVCC=5V

PD

OUTPUTS

■ SYMMETRICALOUTPUTIMPEDANCE:

|I

|=IOL=8 mA(MIN)

OH

■ BALANCEDPROPAGATIONDELAYS:

t

≅ t

PLH

PHL

■ OPERATINGVOLTAGERANGE:

(OPR)= 4.5Vto 5.5V

V

CC

■ PINANDFUNCTIONCOMPATIBLEWITH

74SERIES245

■ IMPROVEDLATCH-UP IMMUNITY

■ LOWNOISE:V

= 0.9V(Max.)

OLP

DESCRIPTION

The 74VHCT245A is an advanced high-speed
CMOS OCTAL BUS TRANSCEIVER (3-STATE)
fabricated with sub-micron silicon gate and
double-layermetal wiring C

2

MOS technology.

This IC is intended for two-way asynchronous
communication between data busses; the
direction of data trasmission is determinedby the

74VHCT245A

OCTAL BUS

TRANSCEIVER(3-STATE)

PRELIMINARY DATA

M

(Micro Package)

(TSSOPPackage)

ORDERCODES :

74VHCT245AM 74VHCT245AT

level of the DIR input. The enable input G can be
used to disable the device so that the busses are
effectivelyisolated.
All inputs and outputs are equipped with
protection circuits against static discharge, giving
them 2KV ESD immunity and transient excess
voltage.

IT IS PROHIBITED TO APPLY A SIGNAL TO A
TERMINAL WHEN IT IS IN OUTPUT MODE
AND WHEN A BUS TERMINAL IS FLOATING
(HIGH IMPEDANCE STATE) IT IS REQUESTED
TO FIX THE INPUT LEVEL BY MEANS OF
EXTERNAL PULL DOWN OR PULL UP
RESISTOR.

T

PIN CONNECTION AND IEC LOGICSYMBOLS

August 1999

1/9

74VHCT245A

INPUT/OUTPUT EQUIVALENTCIRCUIT

INPUT EQUIVALENTCIRCUIT PIN DESCRIPTION

PI N No SYM BO L NAM E AND F U NCTIO N

1 DIR Directional Control

2, 3, 4, 5,

6, 7, 8,9

18, 17, 16,
15, 14, 13,

12, 11

19 G Output Enable Input
10 GND Ground (0V)
20 V

A1 to A8 Data Inputs/Outputs

B1 to B8 Data Inputs/Outputs

CC

Positive Supply Voltage

TRUTH TABLE

GDIRABUSBBUS

L L OUTPUT INPUT A = B
L H INPUT OUTPUT B = A

HXZZZ

X:”H” or”L”
Z:Highimpedance

2/9

INP UT FUNCTI O N OUT P UT

74VHCT245A

ABSOLUTE MAXIMUMRATINGS

Symb o l Para met er Val u e Uni t

V

V
V
V

I

I

OK

I

or I

I

CC

T

T

AbsoluteMaximumRatingsarethosevalues beyond whichdamagetothedevicemayoccur.Functionaloperationunderthesecondition isnotimplied.

1)Outputin OffState

2)HighorLowState.I

RECOMMENDEDOPERATINGCONDITIONS

Symb o l Para met er Value Un it

V

V

V
V

T

dt/dv

1)Outputin OffState

2)HighorLowState.I
from0.8to2V

3)V

IN

Supply Voltage -0.5 to +7.0 V

CC

DC Input Voltage (DIR, G) -0.5 to +7.0 V

I

DC Bus I/O Voltage (see note 1) -0.5 to +7.0 V

I/O

DC Bus I/O Voltage (see note 2) -0.5 to VCC+ 0.5 V

I/O

DC Input Diode Current - 20 mA

IK

DC Output Diode Current
DC Output Current

O

DC VCCor Ground Current ± 75 mA

GND

Storage Temperature -65 to +150

stg

Lead Temperature (10 sec) 300

L

absolutemaximum ratingmustbe observed.

O

Supply Voltage 4.5 to 5.5 V

CC

Input Voltage (DIR, G) 0 to 5.5 V

I

Bus I/O Voltage (see note 1) 0 to 5.5 V

I/O

Bus I/O Voltage (see note 2) 0 to V

I/O

Operating Temperature -40 to +85

op

Input Rise and Fall Time (see note 3) (V

absolutemaximum ratingmustbe observed.

O

=5.0±0.5V)

CC

20 mA

±

25 mA

±

CC

0 to 20 ns/V

o

C

o

C

V

o

C

3/9

74VHCT245A

DC SPECIFICATIONS

Symb o l Para met er Test Con diti o ns Val u e Unit

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

5.5

=8 mA 0.36 0.44

O

VI=VIHor V

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 ELECTRICAL CHARACTERISTICS

(Inputt

r=tf

=3 ns)

Symbol Parameter Test Condition Value Unit

V

t

Propagation Delay

PLH

t

Time

PHL

Output Enable Time 5.0 15 RL=1KΩ 9.0 14.5 1.0 15.5

t

PZL

t

PZH

t

Output Disable Time 5.0 50 RL=1KΩ 9.5 15.0 1.0 16.0

PLZ

t

PHZ

t
t

(*)Voltagerangeis5V ± 0.5V
Note1:Parameterguaranteed bydesign. t

Output to Output Skew

OSLH

Time (note 1)

OSHL

(*)

CC

(V)

5.0 15 4.5 7.5 1.0 8.5

5.0

5.0 50 10.0 15.5 1.0 16.5

5.0 50 1.0 1.0 ns

=|t

soLH

pLHm-tpLHn

CL(pF) TA=25oC -40 to 85oC

Min. Typ. Max. Min. Max.

50

|,t

soHL

=|t

pHLm-tpHLn

|

5.5 8.5 1.0 9.5

ns

ns

ns

4/9

74VHCT245A

CAPACITIVE CHARACTERISTICS

Symbol Parameter Test Conditions Value Unit

=25oC -40 to 85oC

T

A

Min. Typ. Max. Min. Max.

Input Capacitance 4 10 10

C

IN

Bus Input Capacitance 8

C

I/O

Power Dissipation

C

PD

13 pF

Capacitance (note 1)

1)CPDisdefinedasthevalue oftheIC’sinternalequivalentcapacitance whichiscalculated fromtheoperatingcurrentconsumption withoutload.(Referto
TestCircuit).Averageoperting current canbeobtained bythefollowingequation. I

(opr)= CPD• VCC• fIN+ICC/8(percircuit)

CC

DYNAMICSWITCHING CHARACTERISTICS

Symb o l Para met er Test Con diti o ns Val u e Unit

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

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)Maxnumberof outputsdefined as(n).Datainputsaredriven0Vto 3.0V,(n-1)outputsswitching andoneoutput atGND.

3)Maxnumberof datainputs (n)switching.(n-1)switching0V to3.0V.Inputsunder testswitching:3.0Vtothreshold (V

=25oC -40 to 85oC

A

0.6 0.9

-0.9 -0.6

),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 orequ ivalent (includes jig and probe capacitance)

=1KΩorequivalent

R

L=R1

R

ofpulsegenerator(typically50Ω)

T=ZOUT

Open

V

CC

GND

5/9

74VHCT245A

WAVEFORM1: PROPAGATIONDELAYS

(f=1MHz;50% duty cycle)

WAVEFORM2: OUTPUT ENABLE AND DISABLETIME (f=1MHz; 50%duty cycle)

6/9

SO-20 MECHANICALDATA

74VHCT245A

DIM.

MIN. TYP. MAX. MIN. TYP. MAX.

A 2.65 0.104
a1 0.10 0.20 0.004 0.007
a2 2.45 0.096

b 0.35 0.49 0.013 0.019
b1 0.23 0.32 0.009 0.012

C 0.50 0.020

c1 45 (typ.)

D 12.60 13.00 0.496 0.512

E 10.00 10.65 0.393 0.419

e 1.27 0.050
e3 11.43 0.450

F 7.40 7.60 0.291 0.299

L 0.50 1.27 0.19 0.050

M 0.75 0.029

S 8 (max.)

mm inch

P013L

7/9

74VHCT245A

TSSOP20 MECHANICAL DATA

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 0.2 0.0035 0.0079

D 6.4 6.5 6.6 0.252 0.256 0.260

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

A

PIN 1 IDENTIFICATION

8/9

A2

A1

b

e

K

c

L

E

D

E1

1

74VHCT245A

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