Datasheet

ManualsBrandsANALOG DEVICES ManualsLinear ICsADM2490EBRWZ

High Speed, ESD-Protected, Full-Duplex,

iCoupler Isolated RS-485 Transceiver

ADM2490E

Rev. A

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FEATURES

Isolated, full-duplex RS-485/RS-422 transceiver

±8 kV ESD protection on RS-485 input/output pins

16 Mbps data rate

Complies with ANSI TIA/EIA-485-A-1998 and

ISO 8482: 1987(E)

Suitable for 5 V or 3 V operation (V

DD1

)

High common-mode transient immunity: >25 kV/μs

Receiver has open-circuit, fail-safe design

32 nodes on the bus

Thermal shutdown protection

Safety and regulatory approvals

UL recognition: 5000 V rms isolation voltage

for 1 minute per UL 1577

VDE certificate of conformity

DIN EN 60747-5-2 (VDE 0884-10 Part 2): 2003-01

DIN EN 60950 (VDE 0805): 2001-12; EN 60950: 2000

IORM

= 848 V peak

Operating temperature range: −40°C to +105°C

Wide body, 16-lead SOIC package

APPLICATIONS

Isolated RS-485/RS-422 interfaces

Industrial field networks

INTERBUS

Multipoint data transmission systems

FUNCTIONAL BLOCK DIAGRAM

DD1

GND

DD2

GND

GALVANIC ISOLATION

TxD

RxD

ADM2490E

05889-001

Figure 1.

GENERAL DESCRIPTION

The ADM2490E is an isolated data transceiver with ±8 kV ESD

protection that is suitable for high speed, full-duplex communi-

cation on multipoint transmission lines. It is designed for balanced

transmission lines and complies with ANSI TIA/EIA-485-A-1998

and ISO 8482: 1987(E). The device employs Analog Devices, Inc.,

iCoupler® technology to combine a 2-channel isolator, a three-

state differential line driver, and a differential input receiver into

a single package.

The differential transmitter outputs and receiver inputs feature

electrostatic discharge circuitry that provides protection to ±8 kV

using the human body model (HBM). The logic side of the device

can be powered with either a 5 V or a 3 V supply, whereas the

bus side requires an isolated 5 V supply.

The device has current-limiting and thermal shutdown features

to protect against output short circuits and situations where bus

contention could cause excessive power dissipation.

The ADM2490E is available in a wide body, 16-lead SOIC package

and operates over the −40°C to +105°C temperature range.

Summary of content (16 pages)

PAGE 1
High Speed, ESD-Protected, Full-Duplex, iCoupler Isolated RS-485 Transceiver ADM2490E FEATURES FUNCTIONAL BLOCK DIAGRAM VDD2 VDD1 ADM2490E Y GALVANIC ISOLATION TxD RxD GND1 Z A B GND2 05889-001 Isolated, full-duplex RS-485/RS-422 transceiver ±8 kV ESD protection on RS-485 input/output pins 16 Mbps data rate Complies with ANSI TIA/EIA-485-A-1998 and ISO 8482: 1987(E) Suitable for 5 V or 3 V operation (VDD1) High common-mode transient immunity: >25 kV/μs Receiver has open-circuit, fail-safe design
PAGE 2
ADM2490E TABLE OF CONTENTS Features .............................................................................................. 1 Switching Characteristics .................................................................9 Applications ....................................................................................... 1 Typical Performance Characteristics ........................................... 10 Functional Block Diagram ..............................................................
PAGE 3
ADM2490E SPECIFICATIONS All voltages are relative to their respective ground; 2.7 ≤ VDD1 ≤ 5.5 V, 4.5 V ≤ VDD2 ≤ 5.5 V. All minimum/maximum specifications apply over the entire recommended operation range, unless otherwise noted. All typical specifications are at TA = 25°C, VDD1 = VDD2 = 5.0 V, unless otherwise noted. Table 1.
PAGE 4
ADM2490E TIMING SPECIFICATIONS TA = −40°C to +85°C. Table 2.
PAGE 5
ADM2490E REGULATORY INFORMATION Table 5. ADM2490E Approvals Organization UL Approval Type Recognized under the Component Recognition Program of Underwriters Laboratories, Inc. VDE Certified according to DIN EN 60747-5-2 (VDE 0884-10 Part 2): 2003-01, DIN EN 60950 (VDE 0805): 2001-12; EN 60950: 2000 Notes In accordance with UL 1577, each ADM2490E is proof tested by applying an insulation test voltage ≥ 6000 V rms for 1 second (current leakage detection limit = 10 μA).
PAGE 6
ADM2490E ABSOLUTE MAXIMUM RATINGS TA = 25°C, unless otherwise noted. Each voltage is relative to its respective ground. Table 8. Parameter Storage Temperature Range Ambient Operating Temperature Range VDD1 VDD2 Logic Input Voltages Bus Terminal Voltages Logic Output Voltages Average Output Current, per Pin ESD (Human Body Model) on A, B, Y, and Z Pins θJA Thermal Impedance Rating −55°C to +150°C −40°C to +105°C −0.5 V to +7 V −0.5 V to +6 V −0.5 V to VDD1 + 0.5 V −9 V to +14 V −0.5 V to VDD1 + 0.
PAGE 7
ADM2490E PIN CONFIGURATION AND FUNCTION DESCRIPTIONS VDD1 1 16 VDD2 GND1 2 15 GND2 RxD 3 14 A ADM2490E TOP VIEW 13 B GND1 5 (Not to Scale) 12 NC TxD 6 11 Z NC 7 10 Y GND1 8 9 GND2 NC = NO CONNECT 05889-002 NC 4 Figure 2. Pin Configuration Table 9. Pin Function Descriptions Pin No. 1 Mnemonic VDD1 2, 5, 8 3 4, 7, 12 6 9, 15 10 11 13 14 16 GND1 RxD NC TxD GND2 Y Z B A VDD2 Description Power Supply (Logic Side). Decoupling capacitor to GND1 required; capacitor value should be between 0.
PAGE 8
ADM2490E TEST CIRCUITS RL CL1 Y VOD VOC Z 05889-005 RLDIFF 05889-003 RL CL2 Figure 6. Driver Propagation Delay Figure 3. Driver Voltage Measurement 375Ω A 375Ω B Figure 7. Receiver Propagation Delay Figure 4. Driver Voltage Measurement VDD2 VDD1 VDD2 Y GALVANIC ISOLATION RxD GND1 Z 220Ω 100Ω 220Ω A B GND2 GND2 05889-014 TxD VOUT CL 05889-006 VTEST 60Ω 05889-004 VOD3 Figure 5. Supply-Current Measurement Test Circuit (See Figure 10 and Figure 11) Rev.
PAGE 9
ADM2490E SWITCHING CHARACTERISTICS 3V 1.5V 1.5V 0V tPLH tPHL Z VO 1/2VO Y tPWD = |tPLH – tPHL| VOH 90% POINT 90% POINT 10% POINT tR tF 10% POINT Figure 8. Driver Propagation Delay, Rise/Fall Timing A, B 0V 0V tPLH tPHL VOH RxD 1.5V 1.5V VOL Figure 9. Receiver Propagation Delay Rev.
PAGE 10
ADM2490E TYPICAL PERFORMANCE CHARACTERISTICS 3.00 60 2.95 50 tPLH tPHL 40 30 2.80 20 2.75 10 2.70 –40 –20 0 20 40 60 80 100 TEMPERATURE (°C) 0 –40 –20 0 20 40 60 80 100 TEMPERATURE (°C) Figure 13. Receiver Propagation Delay vs. Temperature Figure 10. IDD1 Supply Current vs.
PAGE 11
ADM2490E 4.77 350 4.76 4.75 4.74 VOLTAGE (V) 250 SIDE 2 200 150 50 100 150 CASE TEMPERATURE (°C) 200 4.66 –40 0.30 –4 0.25 VOLTAGE (V) –2 –12 0.05 4.4 4.6 4.8 5.0 VOLTAGE (V) Figure 17. Output Current vs. Receiver Output High Voltage 14 12 10 8 6 4 0.2 0.4 0.6 0.8 1.0 1.2 VOLTAGE (V) 05889-023 2 0 80 100 0 –40 –20 0 20 40 60 80 100 TEMPERATURE (°C) Figure 20. Receiver Output Low Voltage vs. Temperature, IRxD = –4 mA 16 0 60 0.15 0.10 4.2 40 0.20 –10 –14 4.
PAGE 12
ADM2490E CIRCUIT DESCRIPTION ELECTRICAL ISOLATION TRUTH TABLES In the ADM2490E, electrical isolation is implemented on the logic side of the interface. Therefore, the part has two main sections: a digital isolation section and a transceiver section (see Figure 21). The driver input signal, which is applied to the TxD pin and referenced to logic ground (GND1), is coupled across an isolation barrier to appear at the transceiver section referenced to isolated ground (GND2).
PAGE 13
ADM2490E 100 FAIL-SAFE RECEIVER INPUTS The receiver inputs include a fail-safe feature that guarantees a logic high on the RxD pin when the A and B inputs are floating or open-circuited. 10 1 0.1 0.01 0.001 1k 10k 100k 1M 10M MAGNETIC FIELD FREQUENCY (Hz) 100M 05889-010 The ADM2490E contains thermal-shutdown circuitry that protects the part from excessive power dissipation during fault conditions. Shorting the driver outputs to a low impedance source can result in high driver currents.
PAGE 14
ADM2490E APPLICATIONS INFORMATION The ADM2490E requires isolated power capable of 5 V at up to approximately 65 mA (this current is dependent on the data rate and termination resistors used) to be supplied between the VDD2 and the GND2 pins. A transformer driver circuit with a center-tapped transformer and LDO can be used to generate the isolated 5 V supply, as shown in Figure 25. The center-tapped transformer provides electrical isolation of the 5 V power supply.
PAGE 15
ADM2490E TYPICAL APPLICATIONS The ADM2490E transceiver is designed for point-to-point transmission lines. Figure 26 shows a full-duplex point-to-point application. To minimize reflections, terminate the line at the receiver end with a termination resistor. The value of the termination resistor should be equal to the characteristic impedance of the cable. A B Y D RT Z TxD D TxD Z B RT Y ADM2490E A R RxD ADM2490E NOTES 1. RT IS EQUAL TO THE CHARACTERISTIC IMPEDANCE OF THE CABLE. Figure 26.
PAGE 16
ADM2490E OUTLINE DIMENSIONS 10.50 (0.4134) 10.10 (0.3976) 9 16 7.60 (0.2992) 7.40 (0.2913) 8 1.27 (0.0500) BSC 0.30 (0.0118) 0.10 (0.0039) COPLANARITY 0.10 0.51 (0.0201) 0.31 (0.0122) 10.65 (0.4193) 10.00 (0.3937) 0.75 (0.0295) 0.25 (0.0098) 2.65 (0.1043) 2.35 (0.0925) SEATING PLANE 45° 8° 0° 0.33 (0.0130) 0.20 (0.