74F2645SC [FAIRCHILD]

Octal Bus Transceiver with 25ヘ Series Resistors in the Outputs; 八路总线收发器，具有25ヘ系列电阻的输出


型号：	74F2645SC
厂家：	FAIRCHILD SEMICONDUCTOR
描述：	Octal Bus Transceiver with 25ヘ Series Resistors in the Outputs 八路总线收发器，具有25ヘ系列电阻的输出总线收发器逻辑集成电路光电二极管
文件：	总5页 (文件大小：46K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

November 1989

Revised August 1999

74F2645

Octal Bus Transceiver

with 25Ω Series Resistors in the Outputs

General Description

Features

■ 25Ω series resistors in the outputs eliminates the need

This device is an octal bus transceiver designed for asyn-

chronous two-way data flow between the A and B busses

and is functionally equivalent to the 74F645. The 25Ω

series resistors in the outputs reduce ringing and eliminate

the need for external resistors. Both busses are capable of

sinking 12 mA, sourcing 15 mA, have 3-STATE outputs,

and a common output enable pin. The direction of data flow

is determined by the transmit/receive (T/R) input. The

74F2645 is a low power version of the 74F245 with 25Ω

series resistors in the outputs.

for external resistors

■ Designed for asynchronous two-way data flow between

busses

■ Outputs sink 12 mA and source 15 mA

■ Transmit/receive (T/R) input controls the direction of

data flow

■ 74F2645 is a low power version of the 74F245 with 25Ω

series resistors in the outputs

Ordering Code:

Order Number Package Number

Package Description

74F2645SC

M20B

20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide

Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.

Logic Symbol

Connection Diagram

FAST is a registered trademark of Fairchild Semiconductor Corporation.

DS010629

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Unit Loading/Fan Out

Input I_IH/I_IL

U.L.

Pin Names

Description

Output I_OH/I_OL

HIGH/LOW

Output Enable Input (Active LOW)

1.0/1.0

20 µA/−0.6 mA

70 µA/−0.4 mA

−15 mA/12 mA

70 µA/−0.4 mA

−15 mA/12 mA

T/R

Transmit/Receive Input

Side A Inputs or

A₀–A₇

3.5/0.667

750/20

3-STATE Outputs

Side B Inputs or

B₀–B₇

3.5/0.667

750/20

3-STATE Outputs

Functional Description

Function Table

The output enable (OE) is active LOW. If the device is dis-

abled (OE HIGH), the outputs are in the high impedance

state. The transmit/receive input (T/R) controls whether

data is transmitted from the A bus to the B bus or from the

B bus to the A bus. When T/R is LOW, B data is sent to the

A bus. If T/R is HIGH, A data is sent to the B bus.

Inputs

Outputs

T/R

Bus B data to Bus A

Bus A data to Bus B

H = HIGH Voltage Level

L = LOW Voltage Level

X = Don’t Care

Z = High Impedance State

Logic Diagram

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Absolute Maximum Ratings(Note 1)

Recommended Operating

Conditions

Storage Temperature

−65°C to +150°C

Ambient Temperature under Bias

Junction Temperature under Bias

V_CCPin Potential to Ground Pin

Input Voltage (Note 2)

−55°C to +125°C

−55°C to +150°C

−0.5V to +7.0V

Free Air Ambient Temperature

Supply Voltage

0°C to +70°C

+4.5V to +5.5V

−0.5V to +7.0V

Input Current (Note 2)

−30 mA to +5.0 mA

Voltage Applied to Output

in HIGH State (with V_CC= 0V)

Standard Output

−0.5V to V_CC

Note 1: Absolute maximum ratings are values beyond which the device

may be damaged or have its useful life impaired. Functional operation

under these conditions is not implied.

3-STATE Output

−0.5V to +5.5V

Current Applied to Output

in LOW State (Max)

Note 2: Either voltage limit or current limit is sufficient to protect inputs.

twice the rated I_OL(mA)

4000V

ESD Last Passing Voltage (Min)

DC Electrical Characteristics

Symbol

Parameter

Input HIGH Voltage

Min

Typ

Max

Units

Conditions

2.0

Recognized as a HIGH Signal

Recognized as a LOW Signal

Input LOW Voltage

Input Clamp Diode Voltage

Output HIGH

0.8

−1.2

Min

= −18 mA (Non I/O Pins)

10% V

2.0

= −15 mA (A , B )

OH n n

Voltage

Output LOW

10% V

0.50

0.75

= 1 mA (A , B )

n n

Min

Max

0.0

Voltage

= 12 mA (A , B )

n n

Input HIGH

5.0

7.0

0.5

µA

= 2.7V (Non I/O Pins)

= 7.0V (Non I/O Pins)

Current

Input HIGH Current

Breakdown Test

Input HIGH Current

Breakdown (I/O)

Output HIGH

BVI

BVIT

= 5.5V (A , B )

CEX

= V

OUT

Leakage Current

Input Leakage

= 1.9 µA

4.75

Test

All Other Pins Grounded

V = 150 mV

IOD

Output Leakage

Circuit Current

3.75

µA

0.0

All Other Pins Grounded

Input LOW Current

Output Leakage Current

Output Short-Circuit Current

Bus Drainage Test

−0.6

µA

Max

0.0V

Max

= 0.5V (Non I/O Pins)

+ I

= 2.7V (A , B )

n n

OZH

OUT

+ I

−650

−225

500

µA

= 0.5V (A , B )

n n

OZL

−100

µA

= 0V

= 5.25

Power Supply Current (74F2645)

= LOW, V = 0.2V

CCL

= HIGH Z

CCZ

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AC Electrical Characteristics

= +25°C

T = 0°C to +70°C

= +5.0V

= 50 pF

Typ

= +5.0V

C = 50 pF

Symbol

Parameter

Units

Min

1.5

2.5

1.5

2.5

1.5

1.0

Max

6.0

7.5

6.0

7.5

8.0

8.5

7.0

5.5

Min

1.5

2.5

1.5

2.5

2.0

1.0

Max

Propagation Delay

A Input to B Output

Propagation Delay

B Input to A Output

Enable Time

7.0

8.0

7.0

8.0

9.0

8.5

8.0

5.5

PLH

PHL

PLH

PHL

PZH

OE Input to A Output

Disable Time

PZL

PHZ

OE Input to A Output

Enable Time

PLZ

2.5

7.5

8.5

2.0

2.5

9.5

9.0

PZH

OE Input to B Output

Disable Time

PZL

1.5

1.0

6.5

1.0

7.5

6.5

PHZ

OE Input to B Output

PLZ

Basic FAST Circuit Showing Series Resistor Placement

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Physical Dimensions inches (millimeters) unless otherwise noted

20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide

Package Number M20B

Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and

Fairchild reserves the right at any time without notice to change said circuitry and specifications.

LIFE SUPPORT POLICY

FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT

DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD

SEMICONDUCTOR CORPORATION. As used herein:

1. Life support devices or systems are devices or systems

which, (a) are intended for surgical implant into the

body, or (b) support or sustain life, and (c) whose failure

to perform when properly used in accordance with

instructions for use provided in the labeling, can be rea-

sonably expected to result in a significant injury to the

user.

2. A critical component in any component of a life support

device or system whose failure to perform can be rea-

sonably expected to cause the failure of the life support

device or system, or to affect its safety or effectiveness.

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