ST 74VHC245 User Manual

74VHC245

OCTAL BUS

TRANSCEIVER (3-STATE)

■ HIGH SPEED: t ■ LOW POWER DISSIPATION:

I

= 4 µA (MAX.) at TA=25°C

CC

■ HIGH NOISE IMMUNITY:

V

= V

NIH

■ POWER DOWN PROTECTION ON

NIL

= 4.0 ns (TYP.) at VCC = 5V

PD

= 28% VCC (MIN.)

CONTROL INPUTS

■ SYMMETRICAL OUTPUT IMPEDANCE:

|I

| = IOL = 8 mA (MIN)

OH

■ BALANCED PROPAGATION DELAYS:

t

≅ t

PLH

■ OPERATING VOLTAGE RANGE:

V

CC

■ PIN AND FUNCTION COMPATIBLE WITH

PHL

(OPR) = 2V to 5.5V

74 SERIES 245

■ IMPROVED LATCH-UP IMMUNITY ■ LOW NOISE: V

= 0.9V (MAX.)

OLP

DESCRIPTION

The 74VHC245 is an advanced high-speed CMOS OCTAL BUS TRANSCEIVER (3-STATE) fabricated with sub-micron silicon gate and double-layer metal wiring C

2

MOS technology. This IC is intended for two-way asynchronous communication between data busses; the

TSSOPSOP

Table 1: Order Codes

PACKAGE T & R

SOP 74VHC245MTR

TSSOP 74VHC245TTR

direction of data transmission is determined by DIR input. The enable input G

can be used to disable the device so that the busses are effectivel y isolated. All inputs and outputs are equipped with protection circuits against static disc harge, giving them 2KV ESD immunity and transient excess voltage. All floating bus terminals during High Z State must be held HIGH or LOW.

Figure 1: Pin Connection And IEC Logic Symbols

Rev. 6

1/12November 2004

74VHC245

Figure 2: Input Equivalent Circuit Table 2: Pin Description

PIN N° SYMBOL NAME AND FUNCTION

1 DIR Directional Control

2, 3, 4, 5, 6,

7, 8, 9

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

12, 11

19 G 10 GND Ground (0V) 20 V

Table 3: Truth Table

A1 to A8 Data Inputs/Outputs

B1 to B8 Data Inputs/Outputs

Output Enable Input

CC

Positive Supply Voltage

INPUTS FUNCTION

OUTPUT

G

DIR A BUS B BUS

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

HXZZZ

X : Don‘t Care Z : High Impedance

Table 4: Absolute Maximum Ratings

Symbol Parameter Value Unit

V

I

OK

I

or I

I

CC

T

Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied

Supply Voltage

CC

DC Input Voltage (DIR, G)

I

Bus I/O Voltage -0.5 to VCC + 0.5

I/O

DC Output Voltage -0.5 to VCC + 0.5

O

DC Input Diode Current

IK

DC Output Diode Current DC Output Current

O

DC VCC or Ground Current

GND

Storage Temperature

stg

Lead Temperature (10 sec)

L

-0.5 to +7.0 V

-0.5 to +7.0 V V V

- 20 mA

± 20 mA ± 25 mA ± 75 mA

-65 to +150 °C

300 °C

Table 5: Recommended Operating Conditions

Symbol Parameter Value Unit

V

V T

dt/dv

1) VIN from 30 % t o 70% of V

Supply Voltage

CC

Input Voltage (DIR, G)

I

Bus I/O Voltage 0 to V

I/O

Output Voltage 0 to V

O

Operating Temperature

op

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

CC

= 3.3 ± 0.3V)

CC

= 5.0 ± 0.5V)

CC

2 to 5.5 V 0 to 5.5 V

CC CC

-55 to 125 °C 0 to 100

0 to 20

2/12

V V

ns/V

Table 6: DC Specifications

Symbol Parameter

V

High Level Input

IH

Voltage

V

Low Level Input

IL

Voltage

High Level Output

OH

Voltage

Low Level Output

OL

Voltage

I

High Impedance

OZ

Output Leakage Current

Input Leakage

I

Current

I

Quiescent Supply

CC

Current

74VHC245

Test Condition Value

= 25°C

T

V

(V)

CC

A

Min. Typ. Max. Min. Max. Min. Max.

2.0 1.5 1.5 1.5

3.0 to

5.5

0.7V

CC

2.0 0.5 0.5 0.5

3.0 to

5.5

2.0

3.0

4.5

3.0

4.5

2.0

3.0

4.5

3.0

4.5

5.5

0 to

5.5

IO=-50 µA I

=-50 µA

O

=-50 µA

I

O

=-4 mA

I

O

=-8 mA

I

O

IO=50 µA

=50 µA

I

O

=50 µA

I

O

=4 mA

I

O

=8 mA

I

O

= VIH or V

V

I

IL

VO = VCC or GND

V

= 5.5V or GND

I

= VCC or GND

V

I

1.9 2.0 1.9 1.9

2.9 3.0 2.9 2.9

4.4 4.5 4.4 4.4

2.58 2.48 2.4

3.94 3.8 3.7

0.3V

0.0 0.1 0.1 0.1

±0.25 ± 2.5 ± 2.5 µA

-40 to 85°C -55 to 125°C

CC

0.7V

CC

0.3V

CC

0.7V

CC

0.36 0.44 0.55

± 0.1 ± 1 ± 1 µA

44040µA

0.3V

CC

Unit

V

3/12

74VHC245

Table 7: AC Electrical Characteristics (Input tr = tf = 3ns)

Test Condition Value

Symbol Parameter

t

Propagation Delay

PLH

t

t t

t

OSLH

t

OSHL

Time

PHL

Output Disable

PZL

Time

PZH

PLZ

Output Enable

PHZ

Time Output to Output

Skew time (note 1)

V

3.3

5.0

3.3

5.0

3.3

5.0

3.3

5.0

C

CC

(V)

L

(pF)

(*)

15 5.8 8.4 1.0 10.0 1.0 10.0

(*)

50 8.3 11.9 1.0 13.5 1.0 13.5

(**)

15 4.0 5.5 1.0 6.5 1.0 6.5

(**)

50 5.5 7.5 1.0 8.5 1.0 8.5

(*)

15

(*)

50

(**)

15

(**)

50

(*)

50

(**)

50

(*)

50 1.5 1.5 1.5

(**)

50 1.0 1.0 1.0

R

L

R

L

R

L

R

L

R

L

R

L

= 1KΩ = 1KΩ = 1KΩ = 1KΩ = 1KΩ = 1KΩ

T

Min. Typ. Max. Min. Max. Min. Max.

= 25°C

A

-40 to 85°C -55 to 125°C

8.5 13.2 1.0 15.5 1.0 15.5

11.0 16.7 1.0 19.0 1.0 19.0

5.8 8.5 1.0 10.0 1.0 10.0

7.3 10.6 1.0 12.0 1.0 12.0

11.5 15.8 1.0 18.0 1.0 18.0

7.0 9.7 1.0 11.0 1.0 11.0

Unit

ns

(*) Voltage range is 3.3V ± 0.3V (**) Voltage range is 5.0V ± Note 1: Parameter guaranteed by design. t

0.5V

soLH

= |t

pLHm

- t

pLHn

|, t

soHL

= |t

pHLm

- t

pHLn

|

Table 8: Capacitive Characteristics

Test Condition Value

= 25°C

Symbol Parameter

T

A

Min. Typ. Max. Min. Max. Min. Max.

C C C

Input Capacitance

IN

Output

I/O

Capacitance Power Dissipation

PD

Capacitance

410 10 10pF 8pF

21 pF

(note 1)

1) CPD is defined as the value of the IC’s internal equivalent capacitance which is calculated from the operating current consumption without load. (Refer to Test Circuit). Average operating current can be obtained by the following equation. I

-40 to 85°C -55 to 125°C

= CPD x VCC x fIN + ICC/8 (per c ircuit )

CC(opr)

Unit

4/12