ANALOG DEVICES ADM2482E, ADM2487E Service Manual

2.5 kV Isolated RS-485 Transceivers with

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FEATURES

Isolated RS-485/RS-422 transceivers, configurable as half

duplex or full duplex Integrated oscillator driver for external transformer ±15 kV ESD protection on RS-485 input/output pins Complies with TIA/EIA-485-A-98 and ISO 8482:1987(E) Data rate: 500 kbps/16 Mbps 5 V or 3.3 V operation (V 256 nodes on bus True fail-safe receiver inputs 2500 V rms isolation for 1 minute Reinforced insulation 560 V peak High common-mode transient immunity: >25 kV/μs Thermal shutdown protection Operating temperature range: −40°C to +85°C Wide-body, 16-lead SOIC package

APPLICATIONS

Isolated RS-485/RS-422 interfaces Industrial field networks Multipoint data transmission systems

DD1

)

Integrated Transformer Driver

ADM2482E/ADM2487E

FUNCTIONAL BLOCK DIAGRAM

DE

TxD

RxD

RE

V

D1 D2

DD1

OSC

GALVANIC ISOLATION

GND

1

Figure 1.

V

DD2

GND

Y

Z

A

B

2

07379-001

GENERAL DESCRIPTION

The ADM2482E/ADM2487E are isolated data transceivers with ±15 kV ESD protection and are suitable for high speed, halfduplex or full-duplex communication on multipoint transmission lines. For half-duplex operation, the transmitter outputs and receiver inputs share the same transmission line. Transmitter Output Pin Y is linked externally to Receiver Input Pin A, and Transmitter Output Pin Z to Receiver Input Pin B. The parts are designed for balanced transmission lines and comply with TIA/EIA- 485-A-98 and ISO 8482:1987(E).

The devices employ the Analog Devices, Inc., iCoupler® technology to combine a 3-channel isolator, a three-state differential line driver, and a differential input receiver into a single package. An on-chip oscillator outputs a pair of square waveforms that drive an external transformer to provide isolated

power. The logic side of the device can be powered with either

5 V or a 3.3 V supply, and the bus side is powered with an

a

isola

ted 3.3 V supply.

The ADM2482E/ADM2487E driver has an active high enable, and the receiver has an active low enable. The driver output enters a high impedance state when the driver enable signal is low. The receiver output enters a high impedance state when the receiver enable signal is high.

The device has current-limiting and thermal shutdown features to protect against output short circuits and situations where bus contention might cause excessive power dissipation. The part is fully specified over the industrial temperature range of −40°C to +85°C and is available in a 16-lead, wide-body SOIC package.

Rev. 0

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.

ADM2482E/ADM2487E

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REVISION HISTORY

5/08—Revision 0: Initial Version

Rev. 0 | Page 2 of 20

ADM2482E/ADM2487E

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SPECIFICATIONS

All voltages are relative to their respective ground; 3.0 V ≤ V apply over the entire recommended operation range, unless otherwise noted. All typical specifications are at T V

= 3.3 V, unless otherwise noted.

DD2

Table 1.

Parameter Symbol Min Typ Max Unit Test Conditions

SUPPLY CURRENT

Power-Supply Current, Logic Side

TxD/RxD Data Rate < 500 kbps I ADM2487E TxD/RxD Data Rate = 500 kbps I

ADM2482E TxD/RxD Data Rate = 16 Mbps I

Power-Supply Current, Bus Side

TxD/RxD Data Rate < 500 kbps I ADM2487E TxD/RxD Data Rate = 500 kbps I

ADM2482E TxD/RxD Data Rate = 16 Mbps I

DRIVER

Differential Outputs

Differential Output Voltage, Loaded |V

1.5 5.0 V RL = 54 Ω (RS-485), see Figure 2 |V ∆|VOD| for Complementary Output States ∆|VOD| 0.2 V RL = 54 Ω or 100 Ω, see Figure 2 Common-Mode Output Voltage VOC 3.0 V RL = 54 Ω or 100 Ω, see Figure 2 ∆|VOC| for Complementary Output States ∆|VOC| 0.2 V RL = 54 Ω or 100 Ω, see Figure 2 Short-Circuit Output Current IOS 250 mA Output Leakage Current (Y, Z) IO 125 μA

−100 μA

Logic Inputs

Input Threshold Low VIL 0.25 × V Input Threshold High VIH 0.7 × V Input Current II −10 +0.01 +10 μA

RECEIVER

Differential Inputs

Differential Input Threshold Voltage VTH −200 −125 −30 mV −7 V < VCM < +12 V Input Voltage Hysteresis V Input Current (A, B) II 125 μA DE = 0 V, VDD = 0 V or 3.6 V,

−125 μA DE = 0 V, VDD = 0 V or 3.6 V,

Line Input Resistance RIN 96 kΩ −7 V < VCM < +12 V

Logic Outputs

Output Voltage Low V Output Voltage High V Short Circuit Current IOS 100 mA Tristate Output Leakage Current I

3.5 mA Unloaded output

DD1

4 mA Half-duplex configuration,

DD1

6.0 mA Half-duplex configuration,

DD1

17 mA Unloaded output

DD2

40 mA V

DD2

50 mA V

DD2

| 2.0 5.0 V RL = 100 Ω (RS-422), see Figure 2

OD2

| 1.5 5.0 V −7 V ≤ V

OD3

15 mV VOC = 0 V

HYS

0.2 0.4 V I

OLRxD

V

OHRxD

±1 μA V

OZR

≤ 5.5 V, 3.0 V ≤ V

DD1

V

DD1

− 0.3 V

DD1

≤ 3.6 V. All minimum/maximum specifications

DD2

V

DD1

− 0.2 V I

DD1

= 25°C, V

A

R

= 120 Ω, see Figure 8

TERMINATION

= 120 Ω, see Figure 8

TERMINATION

= 3.6 V, half-duplex

DD2

configuration, R see Figure 8

= 3.6 V, half-duplex

DD2

configuration, R see Figure 8

≤ +12 V, see Figure 3

TEST

DE = 0 V,

3.6 V, V DE = 0 V,

3.6 V, V

DE, DE, DE,

V

ORxD

RE

= 12 V

IN

RE

= −7 V

IN

RE

, TxD

RE

, TxD

RE

, TxD

= 12 V

IN

= −7 V

IN

= 1.5 mA, VA − VB = −0.2 V = −1.5 mA, VA − VB = 0.2 V

= 5.0 V, 0 V < VO < V

DD1

= 5 V,

DD1

TERMINATION

= 0 V, VCC = 0 V or

= 120 Ω,

DD1

Rev. 0 | Page 3 of 20

ADM2482E/ADM2487E

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Parameter Symbol Min Typ Max Unit Test Conditions

TRANSFORMER DRIVER

Oscillator Frequency f 230 330 430 kHz V Switch-On Resistance RON 0.5 1.5 Ω Start-Up Voltage V

COMMON-MODE TRANSIENT IMMUNITY

1

CM is the maximum common-mode voltage slew rate that can be sustained while maintaining specification-compliant operation. VCM is the common-mode potential

difference between the logic and bus sides. The transient magnitude is the range over which the common-mode is slewed. The common-mode voltage slew rates apply to both rising and falling common-mode voltage edges.

1

TIMING SPECIFICATIONS

TA = −40°C to +85°C

Table 2. ADM2482E

Parameter Symbol Min Typ Max Unit Test Conditions

DRIVER

Propagation Delay t Output Skew t Rise Time/Fall Time tDR, tDF 15 ns R Enable Time tZL, tZH 120 ns RL = 110 Ω, CL = 50 pF, see Figure 5 and Figure 11 Disable Time tLZ, tHZ 150 ns RL = 110 Ω, CL = 50 pF, see Figure 5 and Figure 11

RECEIVER

Propagation Delay t Output Skew t Enable Time tZL, tZH 13 ns RL = 1 kΩ, CL = 15 pF, see Figure 7 and Figure 12 Disable Time tLZ, tHZ 13 ns RL = 1 kΩ, CL = 15 pF, see Figure 7 and Figure 12

, t

DPLH

DSKEW

PLH

SKEW

100 ns R

DPHL

8 ns R

, t

110 ns CL = 15 pF, see Figure 6 and Figure 10

PHL

8 ns CL = 15 pF, see Figure 6 and Figure 10

400 500 600 kHz V

OSC

2.2 2.5 V

START

= 5.0 V

DD1

= 3.3 V

DD1

25 kV/μs VCM = 1 kV, transient

magnitude = 800 V

= 54 Ω, CL = 100 pF, see Figure 4 and Figure 9

DIFF

= 54 Ω, CL = 100 pF, see Figure 4 and Figure 9

DIFF

= 54 Ω, CL = 100 pF, see Figure 4 and Figure 9

DIFF

Table 3. ADM2487E

Parameter Symbol Min Typ Max Unit Test Conditions

DRIVER

Propagation Delay t Output Skew t Rise Time/Fall Time tDR, tDF 200 1100 ns R

, t

DPLH

DSKEW

250 700 ns R

DPHL

100 ns R

= 54 Ω, CL = 100 pF, see Figure 4 and Figure 9

DIFF

= 54 Ω, CL = 100 pF, see Figure 4 and Figure 9

DIFF

= 54 Ω, CL = 100 pF, see Figure 4 and Figure 9

DIFF

Enable Time tZL, tZH 2.5 μs RL = 110 Ω, CL = 50 pF, see Figure 5 and Figure 11 Disable Time tLZ, tHZ 200 ns RL = 110 Ω, CL = 50 pF, see Figure 5 and Figure 11

RECEIVER

Propagation Delay t Output Skew t

, t

200 ns CL = 15 pF, see Figure 6 and Figure 10

PLH

PHL

30 ns CL = 15 pF, see Figure 6 and Figure 10

SKEW

Enable Time tZL, tZH 13 ns RL = 1 kΩ, CL = 15 pF, see Figure 7 and Figure 12 Disable Time tLZ, tHZ 13 ns RL = 1 kΩ, CL = 15 pF, see Figure 7 and Figure 12

Rev. 0 | Page 4 of 20

ADM2482E/ADM2487E

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PACKAGE CHARACTERISTICS

Table 4.

Parameter Symbol Min Typ Max Unit Test Conditions

Resistance (Input-Output) Capacitance (Input-Output) Input Capacitance Input IC Junction-to-Case Thermal Resistance θ

Output IC Junction-to-Case Thermal Resistance θ

1

This device is considered a 2-terminal device: Pin 1 to Pin 8 are shorted together and Pin 9 to Pin 16 are shorted together.

2

Input capacitance is from any input data pin to ground.

INSULATION AND SAFETY-RELATED SPECIFICATIONS

Table 5.

Parameter Symbol Value Unit Conditions

Rated Dielectric Insulation Voltage 2500 V rms 1-minute duration Maximum Working Insulation Voltage 560 V peak Minimum External Air Gap (Clearance) L(I01) 5.7 min mm

Minimum External Tracking (Creepage) L(I02) 6.1 min mm

Minimum Internal Gap (Internal Clearance) 0.017 min mm Distance through insulation Tracking Resistance (Comparative Tracking Index) CTI >175 V DIN IEC 112/VDE 0303-1

1

2

C

R

1012 Ω

I-O

3 pF f = 1 MHz

I-O

CI 4 pF

33 °C/W

JCI

Thermocouple located at center of package underside

28 °C/W

JCO

Thermocouple located at center of package underside

Measured from input terminals to output terminals, shortest distance through air

Measured from input terminals to output terminals, shortest distance along body

Rev. 0 | Page 5 of 20

ADM2482E/ADM2487E

T

V

–

V

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TEST CIRCUITS

Y

xD V

Z

OD2

Figure 2. Driver Voltage Measurement

Y

xD V

Z

OD3

60Ω

Figure 3. Driver Voltage Measurement

Y

xD

R

DIFF

Z

Figure 4. Driver Propagation Delay

R

L

2

R

L

2

375Ω

CC

OUT

V

OC

07379-003

TxD

DE

Y

S1 S2

Z

R

110Ω

C

L

50pF

L

07379-007

Figure 5. Driver Enable/Disable

A

V

TEST

RE

B

7379-004

OUT

C

L

07379-008

Figure 6. Receiver Propagation Delay

+1.5

C

L

C

L

07379-006

1.5V

RE IN

S1

RE

C

V

L

OUT

V

CC

R

L

S2

07379-009

Figure 7. Receiver Enable/Disable

V

DD1

V

DE

TxD

RxD

RE

GND

GALVANIC ISOLATION

1

Figure 8. Supply-Current Measurement Test Circuit

DD2

GND

Y

120Ω

Z

A

B

2

07379-005

Rev. 0 | Page 6 of 20

ANALOG DEVICES ADM2482E, ADM2487E Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

FEATURES

APPLICATIONS

FUNCTIONAL BLOCK DIAGRAM

GENERAL DESCRIPTION

TABLE OF CONTENTS

REVISION HISTORY

SPECIFICATIONS

TIMING SPECIFICATIONS

PACKAGE CHARACTERISTICS

INSULATION AND SAFETY-RELATED SPECIFICATIONS

TEST CIRCUITS