Analog Devices ADM1486 a Datasheet

5 V, 0.8 mA PROFIBUS

FEATURES

Meets and exceeds EIA RS-485 and EIA RS-422 standards 30 Mbps data rate Recommended for PROFIBUS applications

2.1 V minimum differential output with 54 Ω termination Low power 0.8 mA I Thermal shutdown and short-circuit protection

0.5 ns skew driver and receiver Driver propagation delay: 11 ns Receiver propagation delay: 12 ns High impedance outputs with drivers disabled or power off Superior upgrade for SN65ALS1176 Available in standard 8-lead SOIC package

APPLICATIONS

Industrial field equipment

GENERAL DESCRIPTION

The ADM1486 is a differential line transceiver suitable for high speed bidirectional data communication on multipoint bus transmission lines. It is designed for balanced data transmission, complies with EIA Standards RS-485 and RS-422, and is recommended for PROFIBUS applications. The part contains a differential line driver and a differential line receiver. Both the driver and the receiver may be enabled independently. When disabled or powered down, the driver outputs are high impedance.

The ADM1486 operates from a single 5 V power supply. Excessive power dissipation caused by bus contention or output shorting is prevented by short-circuit protection and thermal circuitry. Short-circuit protection circuits limit the maximum output current to ±200 mA during fault conditions. A thermal shutdown circuit senses if the die temperature rises above 150°C and forces the driver outputs into a high impedance state under this condition.

Up to 50 transceivers may be connected simultaneously on a bus, but only one driver should be enabled at a time. Therefore, it is important that the remaining disabled drivers do not load the bus.

RS-485 Transceiver

ADM1486

FUNCTIONAL BLOCK DIAGRAM

ADM1486

Figure 1.

To ensure this, the ADM1486 driver features high output impedance when disabled and when powered down. This minimizes the loading effect when the transceiver is not being used. The high impedance driver output is maintained over the entire common-mode voltage range from −7 V to +12 V.

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

The ADM1486 is fabricated on BiCMOS, an advanced mixed technology process combining low power CMOS with fast switching bipolar technology. All inputs and outputs contain protection against ESD; all driver outputs feature high source and sink current capability. An epitaxial layer is used to guard against latch-up.

The ADM1486 features extremely fast and closely matched switching, enable, and disable times. Minimal driver propagation delays permit transmission at data rates up to 30 Mbps while low skew minimizes EMI interference.

The part is fully specified over the commercial and industrial temperature range and is available in an 8-lead SOIC package.

GND

02603-001

Rev. A

Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any 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 or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners.

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ADM1486

TABLE OF CONTENTS

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

Applications Information.............................................................. 13

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

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

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

Pin Configuration and Function Descriptions............................. 6

Tes t Ci rc u it s ....................................................................................... 7

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

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

REVISION HISTORY

3/05—Rev. 0 to Rev. A

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

Added PROFIBUS Logo.................................................................. 1

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

Changes to Ordering Guide.......................................................... 15

11/02—Revision 0: Initial Version

Differential Data Transmission ................................................ 13

Cable and Data Rate................................................................... 13

Thermal Shutdown .................................................................... 13

Propagation Delay ...................................................................... 13

Receiver Open-Circuit Fail-Safe............................................... 13

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

Ordering Guide .......................................................................... 15

Rev. A | Page 2 of 16

ADM1486

SPECIFICATIONS

VCC = 5 V ±5%. All specifications T

Table 1.

Parameter Min Typ Max Unit Test Conditions/Comments

DRIVER

Differential Output Voltage, V

2.1 5.0 V VCC = 5 V, R = 50 Ω (RS-422), see Figure 3

2.1 5.0 V R = 27 Ω (RS-485), see Figure 3 V

OD3

∆| VOD | for Complementary Output States 0.2 V R = 27 Ω or 50 Ω, see Figure 3 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 Input Resistance 20 30 kΩ −7 V ≤ VCM ≤ +12 V Input Current (A, B) 0.6 mA VIN = +12 V

−0.35 mA VIN = −7 V Logic Enable Input Current (RE) CMOS Output Voltage Low, V CMOS Output Voltage High, V Short-Circuit Output Current 7 85 mA V Three-State Output Leakage Current ±1.0 µA 0.4 V ≤ V

POWER SUPPLY CURRENT

ICC (Outputs Enabled) 1.2 2.0 mA Outputs unloaded, digital inputs = GND or V ICC (Outputs Disabled) 0.8 1.5 mA Outputs unloaded, digital inputs = GND or V

to T

MIN

= High) 60 200 mA −7 V ≤ VO ≤ +12 V

OUT

= Low) 60 200 mA −7 V ≤ VO ≤ +12 V

OUT

INL

, unless other wise no ted.

MAX

5.0 V R = Infinity, see Figure 3

2.1 5.0 V V

3.0 V R = 27 Ω or 50 Ω, see Figure 3

0.8 V

INH

2.0 V

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

= −7 V to +12 V, see Figure 4

TST

±1.0 µA

0.4 V I

4.0 V I

= +4.0 mA

OUT

= −4.0 mA

OUT

= GND or V

OUT

≤ 2.4 V

OUT

Rev. A | Page 3 of 16

ADM1486

TIMING SPECIFICATIONS

VCC = 5 V ±5%. All specifications T

Table 2.

Parameter Min Typ Max Unit Test Conditions/Comments

DRIVER

Propagation Delay Input to Output t

11 13 ns R

Driver O/P to O/P t

Driver Rise/Fall Time tR, t

SKEW

Driver Enable to Output Valid tZH, t

Driver Disable Timing tHZ, t

Matched Enable Switching

| t

− t

|, | t

− t

AZH

BZL

BZH

| 1 3 ns RL = 110 Ω, CL = 50 pF, see Figure 6

AZL

Matched Disable Switching

| t

− t

|, | t

− t

AHZ

BLZ

BHZ

| 2 5 ns RL = 110 Ω, CL = 50 pF, see Figure 6

ALZ

RECEIVER

Propagation Delay Input to Output t

Skew | t

Receiver Enable tZH, t

Receiver Disable tHZ, t

Guaranteed by characterization.

PLH

− t

| 0.4 2 ns CL = 15 pF1, see Figure 7

PHL

MIN

to T

PLH

, unless other wise no ted.

MAX

, t

4 11 17 ns R

PHL

0.5 2 ns R 8 15 ns R 9 15 ns RL = 110 Ω, CL = 50 pF, see Figure 6 9 15 ns RL = 110 Ω, CL = 50 pF, see Figure 6

, t

6 12 20 ns CL = 15 pF, see Figure 7

PHL

7 13 ns CL = 15 pF, RL = 1 kΩ, see Figure 8 7 13 ns CL = 15 pF, RL = 1 kΩ, see Figure 8

= 54 Ω, CL1 = CL2 = 100 pF, see Figure 5

LDIFF

= 54 Ω, CL1 = CL2 = 100 pF @ TA = 25°C

LDIFF

= 54 Ω, CL1 = CL2 = 100 pF, see Figure 5

LDIFF

= 54 Ω, CL1 = CL2 = 100 pF, see Figure 5

LDIFF

Rev. A | Page 4 of 16

ADM1486

ABSOLUTE MAXIMUM RATINGS

TA = 25°C, unless otherwise noted.

Table 3.

Parameter Rating

Inputs

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

Receiver Inputs (A, B) −9 V to +14 V

Outputs

Driver Outputs −9 V to +14 V Receiver Outputs −0.5 V to VCC + 0.5 V

Power Dissipation 8-Lead SOIC 450 mW

θJA, Thermal Impedance 170°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 sec) 300°C

Vapor Phase (60 sec) 215°C Infrared (15 sec) 220°C

7 V

−0.3 V to V

+ 0.3 V

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 indicated in the in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions 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. A | Page 5 of 16

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