ST 74VHCT244A User Manual

74VHCT244A

OCTAL BUS BUFFER

WITH 3 STATE OUTPUTS (NON INVERTED)

■ HIGH SPEED: t

■ LOW POWER DISSIPATION:

I

= 4 µA (MAX.) at TA=25°C

CC

■ COMPATIBLE WITH TTL OUTP U TS:

V

= 2V (M IN.), V

IH

■ POWER DOWN PROTECTION ON INPUTS

= 5.4 ns (TYP.) at VCC = 5V

PD

= 0.8V (MAX)

IL

& OUTPUTS

■ SYMMETRICAL OUTPUT IMPEDANCE:

| = IOL = 8 mA (MIN)

|I

OH

■ BALANCED PROPAGATION DELAYS:

≅ t

t

PLH

■ OPERATING VOLTAGE RANGE:

V

CC

■ PIN AND FUNCTION COMPATIBLE WITH

PHL

(OPR) = 4.5V to 5.5V

74 SERIES 244

■ IMPROVED LATCH-UP IMMUNITY

■ LOW NOISE: V

= 0.9V (MAX.)

OLP

DESCRIPTION

The 74VHCT244A is an advanced high-speed CMOS OCTAL BUS BUFFER (3-STATE) fabricated with sub-micron silicon gate and double-layer metal wiring C

enable input governs four BUS BUFFERs.

G

2

MOS technology.

TSSOPSOP

Table 1: Order Codes

PACKAGE T & R

SOP 74VHCT244AMTR

TSSOP 74VHCT244ATTR

This device is designed to be used with 3 state memory address drivers, etc. Power down protection is provided on all inputs and outputs and 0 to 7V can be accepted on inputs with no regard to the supply voltage. This device can be used t o interf ace 5V to 3V s ince al l inputs are equipped with TTL threshold. All inputs and outputs are equipped with protection circuits against static disc harge, giving them 2KV ESD immunity and transient excess voltage.

Figure 1: Pin Connection And IEC Logic Symbols

Rev. 4

1/12December 2004

74VHCT244A

Figure 2: Input Equivalent Circuit Table 2: Pin Description

PIN N° SYMBOL NAME AND FUNCTION

11G 2, 4, 6, 8 1A1 to 1A4 Data Inputs 9, 7, 5, 3 2Y1 to 2Y4 Data Outputs

11, 13, 15, 172A1 to 2A4 Data Inputs

18, 16, 14, 121Y1 to 1Y4 Data Outputs

Output Enable Input

19 2G

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

CC

Positive Supply Voltage

Table 3: Truth Table

INPUTS OUTPUT

G

An Yn

LLL LHH

HXZ

X : Don’t Care Z : High Impedance

Table 4: Absolute Maximum Ratings

Symbol Parameter Value Unit

V

V V V

I

OK

I

or 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

1) Output in OFF State

2) High or Low State

Supply Voltage

CC

DC Input Voltage

I

DC Output Voltage (see note 1)

O

DC Output Voltage (see note 2) -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

- 20 mA

± 20 mA ± 25 mA ± 50 mA

-65 to +150 °C

300 °C

2/12

74VHCT244A

Table 5: Recommended Operating Conditions

Symbol Parameter Value Unit

V

V V V T

dt/dv

1)Output in OFF State

2) High or Low State

3) VIN from 0. 8V to 2V

Table 6: DC Specifications

Symbol Parameter

V

IH

V

IL

V

OH

V

OL

I

OZ

I

CC

+I

CC

I

OPD

Supply Voltage

CC

Input Voltage

I

Output Voltage (see note 1)

O

Output Voltage (see note 2) 0 to V

O

Operating Temperature

op

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

= 5.0 ± 0.5V)

CC

Test Condition Value

= 25°C

T

A

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

222V

0.8 0.8 0.8 V

4.4 4.5 4.4 4.4

3.94 3.8 3.7

0.0 0.1 0.1 0.1

0.36 0.44 0.55

±0.25 ± 2.5 ± 2.5 µA

± 0.1 ± 1.0 ± 1.0 µA

22020µA

1.35 1.5 1.5 mA

0.5 5.0 5.0 µA

High Level Input Voltage

Low Level Input Voltage

High Level Output Voltage

Low Level Output Voltage

High Impedance Output Leakage Current

Input Leakage Current

Quiescent Supply Current

Additional Worst Case Supply Current

Output Leakage Current

V

CC

(V)

4.5 to

5.5

4.5 to

5.5

4.5

4.5 to

5.5

0 to

5.5

0

=-50 µA

I

O

=-8 mA

I

O

IO=50 µA

I

=8 mA

O

= VIH or V

V

I

IL

VO = 0V to 5.5V

V

= 5.5V or GND

I

= VCC or GND

V

I

One Input at 3.4V, other input at V

CC

or GND

= 5.5V

V

OUT

4.5 to 5.5 V 0 to 5.5 V 0 to 5.5 V

CC

-55 to 125 °C 0 to 20 ns/V

-40 to 85°C -55 to 125°C

V

Unit

V

Table 7: AC Electrical Characteristics (Input t

Test Condition Value

Symbol Parameter

t

Propagation Delay

PLH PHL

PLZ

PHZ

PZL

PZH

Time Output Disable

Time Output Enable

Time

t t

t

(*) Voltage range is 5.0V ± 0.5V

V

(*)

(V)

C

(pF)

L

CC

5.0 15 5.4 7.4 1.0 8.5 1.0 8.5

5.0 50 5.9 8.4 1.0 9.5 1.0 9.5

5.0 15

5.0 50 8.2 11.4 1.0 13.0 1.0 13.0

RL = 1KΩ

5.0 50 RL = 1K Ω 8.8 11.4 1.0 13.0 1.0 13.0 ns

= tf = 3ns)

r

= 25°C

T

A

-40 to 85°C -55 to 125°C

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

7.7 10.4 1.0 12.0 1.0 12.0

Unit

ns

3/12

74VHCT244A

Table 8: Capacitive Characteristics

Test Condition Value

= 25°C

Symbol Parameter

T

A

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

C

Input Capacitance

IN

Output

OUT

Capacitance Power Dissipation

PD

Capacitance

610 10 10pF

10 pF

18 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

Table 9: Dynamic Switching Characteristics

Test Condition Value

= 25°C

Symbol Parameter

V V

Dynamic Low

OLP

Voltage Quiet

OLV

Output (note 1, 2) Dynamic High

V

IHD

Voltage Input (note 1, 3)

Dynamic Low

V

ILD

Voltage Input (note 1, 3)

V

CC

(V)

5.0

= 50 pF

5.0 2.0

C

L

5.0 0.8

T

A

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

0.9 1.1

-1.1 -0.9

-40 to 85°C -55 to 125°C

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

CC(opr)

-40 to 85°C -55 to 125°C

Unit

V

1) Worst case package.

2) Max number of outp ut s defined as (n). Data inpu t s are driven 0V to 3.0V, (n-1) outputs switc hi ng and one output at GND.

3) Max number of data inputs (n) switching. (n-1) switching 0V to 3.0V. Inputs under test switching: 3.0V to threshold (V (V

), f=1MHz.

IHD

ILD

), 0V to thresho l d

4/12