National Semiconductor LMS75ALS176A Technical data

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LMS75ALS176A
Differential Bus Transceivers

LMS75ALS176A Differential Bus Transceivers

April 2003

General Description

The LMS75ALS176A is a differential bus/line transceiver
designed for bidirectional data communication on multipoint
bus transmission lines. It is designed for balanced transmis­sion lines. It meets ANSI Standards TIA/EIA RS422-B, TIA/
EIA RS485-A and ITU recommendation V.11 and X.27. The
LMS75ALS176A combines a TRI-STATE
driver and differential input receiver, both of which operate
from a single 5.0V power supply. The driver and receiver
have an active high and active low enable, respectively, that
can be externally connected to function as a direction con­trol. The driver and receiver differential inputs are internally
connected to form differential input/output (I/O) bus ports
that are designed to offer minimum loading to bus whenever
the driver is disabled or when V
wide positive and negative common mode voltage ranges,
making the device suitable for multipoint applications in
noisy environments. The LMS75ALS176A is available in a
8-Pin SOIC package. It is a drop-in socket replacement to
TI’s SN75ALS176A.

CC

™

differential line

= 0V. These ports feature

Typical Application

Features

n Bidirectional transceiver
n Meet ANSI standard RS-485-A and RS-422-B
n Low skew, 2ns
n Low supply current, 8mA (max.)
n Wide input and output voltage range
n High output drive capacity
n Thermal shutdown protection
n Open circuit fail-safe for receiver
n Receiver input sensitivity
n Receiver input hysteresis 10mV (min.)
n Single supply voltage operation, 5V
n Glitch free power-up and power-down operation
n Data rates up to 35 Mbaud
n Pin and functional compatible with TI’s SN75ALS176A
n 8-Pin SOIC

±

60mA

±

200mV

Applications

n Network hubs, bridges, and routers
n Point of sales equipment (ATM, barcode readers,…)
n Industrial programmable logic controllers
n High speed parallel and serial applications
n Multipoint applications with noisy environment

A Typical multipoint application is shown in the above figure. Terminating resistors, RT, are typically required but only located at the two ends of the cable.
Pull up and pull down resistors maybe required at the end of the bus to provide failsafe biasing. The biasing resistors provide a bias to the cable when all
drivers are in TRI-STATE, See National Application Note, AN-847 for further information.

© 2003 National Semiconductor Corporation DS200478 www.national.com

20047801

Connection Diagram

LMS75ALS176A

8-Pin SOIC

Top View

20047802

Ordering Information

Package Part Number Package Marking Transport Media NSC Drawing

8-Pin SOIC

LMS75ALS176AM

LMS75ALS176AMX 2.5k Units Tape and Reel

LMS75LS176A

Rail

Truth Table

DRIVER SECTION

RE

XHHHL

XHL LH

XLXZZ

RECEIVER SECTION

RE

LL ≥ +0.2V H

LL ≤ −0.2V L

HX X Z

L L OPEN

Note:*= Non Terminated, Open Input only

X = Irrelevant

Z = TRI-STATE

H = High level

L = Low level

DE DI A B

DE A-B RO

*

M08A

H

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LMS75ALS176A

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

Supply Voltage, V

Voltage Range at Any Bus
Terminal −7V to 12V

Input Voltage, V

Package Thermal Impedance, θ

Junction Temperature (Note 3) 150˚C

Operating Free-Air Temperature
Range, T

A

Storage Temperature Range −65˚C to 150˚C

Soldering Information

Infrared or Convection (20 sec.) 235˚C

ESD Rating (Note 4) 2KV

(Note 2) 7V

CC

(DI, DE, or RE) −0.3V to VCC+ 0.3V

IN

JA

125C/W

0˚C to 70˚C

Operating Ratings

Supply Voltage, V

Voltage at any Bus Terminal
(Separately or Common Mode)

V

or V

IN

IC

High-Level Input Voltage, V
(Note 5)

Low-Level Input Voltage, V
(Note 5)

Differential Input Voltage, V
(Note 6)

High-Level Output

Driver, I

Receiver, I

Low-Level Output

Driver, I

Receiver, I

CC

OH

OH

OL

OL

Min Nom Max

4.75 5.0 5.25 V

IH

IL

ID

2V

12−7V

0.8 V

±

12 V

−60 mA

−400 µA

60 mA

8mA

Electrical Characteristics

VCC= 5V, TA= 0˚C to 70˚C

Symbol Parameter Conditions Min Typ Max Units

Driver Section

V

CL

V

O

|V

OD1

|V

OD2

V

OD3

∆V

OD

V

OC

∆V

OC

I

O

I

IH

I

IL

I

OSD

I

CC

Switching Characteristics

(OD) Differential Output Delay

t

d

Input Clamp Voltage II= −18mA −1.5 V

Output Voltage IO=0 0 6 V

| Differential Output Voltage IO= 0 1.5 6 V

| Differential Output Voltage RL= 100Ω,2

R

=54Ω 1.5 1.9 5

L

Differential Output Voltage V

Change in Magnitude of

= −7V to 12 V 1.5 5 V

TEST

=54Ω or 100Ω

R

L

±

0.2 V
Differential Output Voltage
(Note 7)

Common-Mode Output
Voltage

Change in Magnitude of

RL=54Ω or 100Ω 3

=54Ω or 100Ω

R

L

±

−1

0.2 V
Differential Output Voltage
(Note 7)

Output Current Output Disabled

(Note 8)

High-Level

VIN= 2.4V 20 µA

VO= 12V 1

V

= −7V −0.8

O

mA

Input Current

Low-Level

VIN= 0.4V −400 µA

Input Current

Short-Circuit Output Current VO= −7V −250

V

= 0 −150

O

V

O=VCC

V

= 8V 250

O

Supply Current No Load Outputs

250

4.8 8 mA

mA

Enabled or
Disabled

RL=54Ω ,CL= 50pF 3 7 14 ns

Time

V

V

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Electrical Characteristics (Continued)

VCC= 5V, TA= 0˚C to 70˚C

Symbol Parameter Conditions Min Typ Max Units

t

(OD) Differential Output Transition

t

LMS75ALS176A

t

sk(p)

t

sk(lim)

t

PZH

Time

Pulse Skew, (|t

Pulse Skew RL=54Ω,CL= 50pF

Output Enable Time to High
Level

t

PZL

Output Enable Time to Low
Level

t

PHZ

Output Disable Time from
High Level

t

PLZ

Output Disable Time from
Low Level

Receiver Section

V

TH+

Positive-Going Input
Threshold Voltage

V

TH−

Negative-Going Input
Threshold Voltage

∆V

V

V

V

I

TH

CL

OH

OL

OZ

Hysteresis Voltage
(V

TH+-VTH−

)

Enable-Input Clamp Voltage II= −18mA 1.5 V

High-Level Output Voltage VID= 200mV, IOH= −400µA 2.7 V

Low-Level Output Voltage VID= −200mV, IOL= 8mA 0.45 V

High-Impedance-State Output
Current

I

IN

I

IH

Line Input Current Other Input = 0V,

High-Level Enable-Input
Current

I

IL

Low-Level Enable-Input
Current

R

I

I

IN

OSR

CC

Input Resistance 12 20 kΩ

Short-Circuit Output Current VID= 200mV, VO= 0V −15 −85 mA

Supply Current No Load Outputs

d(ODH-td(ODL

RL=54Ω,CL= 50pF 8 ns

|) RL=54Ω,CL= 50pF 0 3 ns

4ns

(Note 9)

RL= 110Ω,CL= 50pF 18 50 ns

RL= 110Ω,CL= 50pF 18 35 ns

RL= 110Ω,CL= 50pF 9 35 ns

RL= 110Ω,CL= 50pF 10 17 ns

VO= 2.7V, IO= −0.4mA 0.2 V

VO= 0.5V, IO= 8mA −0.2 V

10 mV

VO= 0.4V to 2.4V

±

20 µA

VIN= 12V 1

(Note 5)

V

= −7V −0.8

IN

VIH= 2.7V 20 µA

VIL= 0.4V −100 µA

4.8 8 mA
Enabled or
Disabled

mA

Switching Characteristics

t

PD

t

sk(p)

t

sk(lim)

Propagation Delay Time VID= −1.5V to 1.5V, CL= 15pF 8 18 30 ns

Pulse Skew (|t

PLH-tPHL

|) VID= −1.5V to 1.5V, CL= 15pF 2 ns

Pulse Skew RL=54Ω ,CL= 50pF

(Note 9)

t

PZH

Output Enable Time to High

CL= 15pF 5 35 ns

Level

t

PZL

Output Enable Time to Low

CL= 15pF 5 35 ns

Level

t

PHZ

Output Disable Time from

CL= 15pF 20 35 ns

High Level

t

PLZ

Output Disable Time from

CL= 15pF 10 17 ns

Low Level

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7.5 ns