Analog Devices ADM488 9 c Datasheet

Full-Duplex, Low Power,

Slew Rate Limited, EIA RS-485 Transceivers

FEATURES

Meets EIA RS-485 and RS-422 standards
250 kbps data rate
Single 5 V ± 10% supply

−7 V to +12 V bus common-mode range
12 kΩ input impedance
2 kV EFT protection meets IEC1000-4-4
High EM immunity meets IEC1000-4-3
Reduced slew rate for low EM interference
Short-circuit protection
Excellent noise immunity
30 µA supply current

APPLICATIONS

Low power RS-485 and RS-422 systems
DTE-DCE interface
Packet switching
Local area networks
Data concentration
Data multiplexers
Integrated services digital network (ISDN)

GENERAL DESCRIPTION

The ADM488 and ADM489 are low power, differential line
transceivers suitable for communication on multipoint bus
transmission lines. They are intended for balanced data
transmission and comply with both EIA Standards RS-485 and
RS-422. Both products contain a single differential line driver
and a single differential line receiver, making them suitable for
full-duplex data transfer. The ADM489 contains an additional
receiver and driver enable control.

The input impedance is 12 kΩ, allowing 32 transceivers to be
connected on the bus.

The ADM488/ADM489 operate from a single 5 V ± 10% power
supply. Excessive power dissipation caused by bus contention or

ADM488/ADM489

FUNCTIONAL BLOCK DIAGRAMS

ADM488

RO

DI

RO
RE

DE

DI

R

D

Figure 1.

ADM489

R

D

Figure 2.

output shorting is prevented by a thermal shutdown circuit.
This feature forces the driver output into a high impedance state
if, during fault conditions, a significant temperature increase is
detected in the internal driver circuitry.

The receiver contains a fail-safe feature that results in a logic
high output state if the inputs are unconnected (floating).

The ADM488/ADM489 are fabricated on BiCMOS, an
advanced mixed technology process combining low power
CMOS with fast switching bipolar technology.

The ADM488/ADM489 are fully specified over the industrial
temperature range and are available in PDIP, SOIC, and TSSOP
packages.

A

B

Z

Y

A

B

Z

Y

00079-001

00079-002

Rev. C

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infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
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ADM488/ADM489

TABLE OF CONTENTS

Specifications..................................................................................... 3

Fast Transient Burst Immunity (IEC1000-4-4) ...................... 11

Timing Specifications .................................................................. 4

Absolute Maximum Ratings............................................................ 5

ESD Caution.................................................................................. 5

Pin Configurations and Function Descriptions ........................... 6

Test C ir c uit s ................................................................................... 7

Switching Characteristics ............................................................ 8

Typical Performance Characteristics ............................................. 9

Theory of Operation ...................................................................... 11

EFT Transient Protection Scheme............................................ 11

REVISION HISTORY

11/04–Data Sheet Changed from Rev. B to Rev. C

Updated Format ................................................................. ..Universal

Changes to Receiving Truth Table Inputs ......................................11

Renamed General Information to Theory of Operation..............12

Radiated Immunity (IEC1000-4-3) ......................................... 12

EMI Emissions............................................................................ 13

Conducted Emissions ................................................................ 13

Application Information................................................................ 14

Differential Data Transmission ................................................ 14

Cable and Data Rate................................................................... 14

Outline Dimensions ....................................................................... 15

Ordering Guide .......................................................................... 16

Updated Outline Dimensions..........................................................15

Changes to Ordering Guide.............................................................16

5/01–Data Sheet Changed from Rev. A to Rev. B

Changed to Absolute Maximum Ratings ........................................3

3/01–Data Sheet Changed from Rev. 0 to Rev. A

Changed to ESD specification, Absolute Maximum Ratings .......3

6/97–Revision 0: Initial Version

Rev. C | Page 2 of 16

ADM488/ADM489

SPECIFICATIONS

VCC = 5 V ± 10%. All specifications T

Table 1.

Parameter Min Typ Max Unit Test Conditions/Comments

DRIVER

Differential Output Voltage, V

OD

2.0 5.0 V VCC = 5 V, R = 50 Ω (RS-422), Figure 6

1.5 5.0 V R = 27 Ω (RS-485), Figure 6

1.5 5.0 V V
∆|VOD| for Complementary Output States 0.2 V R = 27 Ω or 50 Ω, Figure 6
Common-Mode Output Voltage, V
∆ |VOC| for Complementary Output States 0.2 V R = 27 Ω or 50 Ω
Output Short-Circuit Current (V
Output Short-Circuit Current (V
CMOS Input Logic Threshold Low, V
CMOS Input Logic Threshold High, V
Logic Input Current (DE, DI) ±1.0 µA

RECEIVER

Differential Input Threshold Voltage, V
Input Voltage Hysteresis, ∆ V

TH

Input Resistance 12 kΩ −7 V ≤ VCM ≤ +12 V
Input Current (A, B) 1 mA VIN = 12 V

−0.8 mA VIN = –7 V
Logic Enable Input Current (RE)
CMOS Output Voltage Low, V
CMOSOutput Voltage High, V

OL

OH

Short-Circuit Output Current 7 85 mA V
Three-State Output Leakage Current ±1.0 µA 0.4 V ≤ V

POWER SUPPLY CURRENT Outputs unloaded, receivers enabled

I

CC

37 74 µA DE = 5 V (enabled)

MIN

to T

, unless otherwise noted.

MAX

5.0 V R = ∞, Figure 6

= –7 V to +12 V, Figure 7, VCC = 5 V ± 5%

TST

OC

= High) 250 mA −7 V ≤ VO ≤ +12 V

OUT

= Low) 250 mA −7 V ≤ VO ≤ +12 V

OUT

INL

INH

TH

3 V R = 27 Ω or 50 Ω, Figure 6

1.4 0.8 V

2.0 1.4 V

−0.2 +0.2 V −7 V ≤ VCM ≤ +12 V
70 mV VCM = 0 V

±1 µA

0.4 V I

4.0 V I

= +4.0 mA

OUT

= −4.0 mA

OUT

= GND or V

OUT

OUT

30 60 µA DE = 0 V (disabled)

CC

≤ +2.4 V

Rev. C | Page 3 of 16

ADM488/ADM489

TIMING SPECIFICATIONS

VCC = 5 V ± 10%. All specifications T

Table 2.

Parameter Min Typ Max Unit Test Conditions/Comments

DRIVER

Propagation Delay Input to Output, T

Driver O/P to OP, T

Driver Rise/Fall Time, TR, T

SKEW

F

Driver Enable to Output Valid 250 2000 ns RL = 500 Ω, CL = 100 pF, Figure 7

Driver Disable Timing 300 3000 ns RL = 500 Ω, CL = 15 pF, Figure 7

Data Rate 250 kbps
RECEIVER

Propagation Delay Input to Output, T

Skew | T

Receiver Enable, T

Receiver Disable, T

PLH

− T

| 100 ns

PHL

EN1

EN2

Data Rate 250 kbps

MIN

to T

PLH

PLH

, unless otherwise noted.

MAX

, T

PHL

250 2000 ns RL Differential = 54 Ω, CL1 = CL2 = 100 pF, Figure 10
100 800 ns RL Differential = 54 Ω, CL1 = CL2 = 100 pF, Figure 10
250 2000 ns RL Differential = 54 Ω, CL1 = CL2 = 100 pF, Figure 10

, T

PHL

250 2000 ns CL = 15 pF, Figure 10

10 50 ns RL = 1 kΩ, CL = 15 pF, Figure 9
10 50 ns RL = 1 kΩ, CL = 15 pF, Figure 9

Rev. C | Page 4 of 16

ADM488/ADM489

ABSOLUTE MAXIMUM RATINGS

TA = 25°C, unless otherwise noted.

Table 3.

Parameter Rating

V

CC

Inputs

Driver Input (DI) −0.3 V to VCC + 0.3 V
Control Inputs (DE, RE)
Receiver Inputs (A, B) −14 V to +14 V

Outputs

Driver Outputs −14 V to +12.5 V
Receiver Output −0.5 V to VCC + 0.5 V

Power Dissipation 8-Lead PDIP 700 mW

θJA, Thermal Impedance 120°C/W

Power Dissipation 8-Lead SOIC 520 mW

θJA, Thermal Impedance 110°C/W

Power Dissipation 14-Lead PDIP 800 mW

θJA, Thermal Impedance 140°C/W

Power Dissipation 14-Lead SOIC 800 mW

θJA, Thermal Impedance 120°C/W

Power Dissipation 16-Lead TSSOP 800 mW

θJA, Thermal Impedance 150°C/W

Operating Temperature Range

Industrial (A Version) −40°C to +85°C
Storage Temperature Range −65°C to +150°C
Lead Temperature (Soldering, 10 secs) 300°C

Vapor Phase (60 secs) 215°C

Infrared (15 secs) 220°C
ESD Association S5.1 HBM Standard 3 kV
EFT Rating, IEC1000-4-4 2 kV

7 V

−0.3 V to V

+ 0.3 V

CC

Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those listed in the operational sections
of this specification is not implied. Exposure to absolute
maximum ratings for extended periods of time may affect
device reliability.

ESD CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.

Rev. C | Page 5 of 16