Datasheet

ManualsBrandsANALOG DEVICES ManualsLinear ICsN/A ADuM2483BRWZ Type (misc.) Insulated RS485 coupler ADuM2483BRWZ Type (misc.) Insulate

Half-Duplex,

Coupler

Isolated RS-485 Transceiver

ADM2483

Rev. B

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FEATURES

RS-485 transceiver with electrical data isolation

Complies with ANSI TIA/EIA RS-485-A and ISO 8482: 1987(E)

500 kbps data rate

Slew rate-limited driver outputs

Low power operation: 2.5 mA max

Suitable for 5 V or 3 V operations (V

DD1

)

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

True fail-safe receiver inputs

Chatter-free power-up/power-down protection

256 nodes on bus

Thermal shutdown protection

Safety and regulatory approvals

UL recognition: 2500 V

rms

for 1 minute per UL 1577

CSA Component Acceptance Notice #5A

VDE Certificate of Conformity

DIN EN 60747-5-2 (VDE 0884 Rev. 2): 2003-01

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

IORM

= 560 V peak

Operating temperature range: −40°C to +85°C

APPLICATIONS

Low power RS-485/RS-422 networks

Isolated interfaces

Building control networks

Multipoint data transmission systems

FUNCTIONAL BLOCK DIAGRAM

DD1

GND

DD2

TxD

RxD

GALVANIC ISOLATION

04736-001

ADM2483

Figure 1.

GENERAL DESCRIPTION

The ADM2483 differential bus transceiver is an integrated,

galvanically isolated component designed for bidirectional data

communication on balanced, multipoint bus transmission lines.

It complies with ANSI EIA/TIA-485-A and ISO 8482: 1987(E).

Using Analog Devices’ iCoupler technology, the ADM2483

combines a 3-channel isolator, a three-state differential line

driver, and a differential input receiver into a single package.

The logic side of the device is powered with either a 5 V or 3 V

supply, and the bus side uses a 5 V supply only.

The ADM2483 is slew-limited to reduce reflections with

improperly terminated transmission lines. The controlled slew

rate limits the data rate to 500 kbps. The device’s input impedance

is 96 kΩ, allowing up to 256 transceivers on the bus. Its driver

has an active-high enable feature. The driver differential outputs

and receiver differential inputs are connected internally to form

a differential I/O port. When the driver is disabled or when

DD1

or V

DD2

= 0 V, this imposes minimal loading on the bus.

An active-high receiver disable feature, which causes the receive

output to enter a high impedance state, is provided as well.

The receiver inputs have a true fail-safe feature that ensures a

logic-high receiver output level when the inputs are open or

shorted. This guarantees that the receiver outputs are in a

known state before communication begins and at the point

when communication ends.

Current limiting and thermal shutdown features protect against

output short circuits and bus contention situations that might

cause excessive power dissipation. The part is fully specified

over the industrial temperature range and is available in a

16-lead, wide body SOIC package.

Summary of content (20 pages)

PAGE 1
Half-Duplex, iCoupler® Isolated RS-485 Transceiver ADM2483 VDD1 VDD2 ADM2483 DE TxD PV RxD A B 04736-001 RS-485 transceiver with electrical data isolation Complies with ANSI TIA/EIA RS-485-A and ISO 8482: 1987(E) 500 kbps data rate Slew rate-limited driver outputs Low power operation: 2.
PAGE 2
ADM2483 TABLE OF CONTENTS Specifications..................................................................................... 3 Circuit Description......................................................................... 14 Timing Specifications....................................................................... 4 Electrical Isolation...................................................................... 14 Absolute Maximum Ratings............................................................
PAGE 3
ADM2483 SPECIFICATIONS 2.7 ≤ VDD1 ≤ 5.5 V, 4.75 V ≤ VDD2 ≤ 5.25 V, TA = TMIN to TMAX, unless otherwise noted. Table 1.
PAGE 4
ADM2483 TIMING SPECIFICATIONS 2.7 ≤ VDD1 ≤ 5.5 V, 4.75 V ≤ VDD2 ≤ 5.25 V, TA = TMIN to TMAX, unless otherwise noted. Table 2.
PAGE 5
ADM2483 ABSOLUTE MAXIMUM RATINGS TA = 25°C, unless otherwise noted. All voltages are relative to their respective ground. Table 3. Parameter VDD1 VDD2 Digital Input Voltage (DE, RE, TxD) Digital Output Voltage RxD Driver Output/Receiver Input Voltage ESD Rating: Contact (Human Body Model) (A, B Pins) Operating Temperature Range Storage Temperature Range Average Output Current per Pin θJA Thermal Impedance Lead Temperature Soldering (10 sec) Vapor Phase (60 sec) Infrared (15 sec) Rating −0.5 V to +7 V −0.
PAGE 6
ADM2483 PACKAGE CHARACTERISTICS Table 4.
PAGE 7
ADM2483 VDE 0884 INSULATION CHARACTERISTICS This isolator is suitable for basic electrical isolation only within this safety limit data. Maintenance of this safety data shall be ensured by means of protective circuits. An asterisk (*) on the physical package denotes VDE 0884 approval for 560 V peak working voltage. Table 7.
PAGE 8
ADM2483 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS VDD1 1 16 VDD2 GND11 2 15 GND21 RxD 3 14 NC RE 4 ADM2483 13 B TOP VIEW DE 5 (Not to Scale) 12 A TxD 6 11 NC PV 7 10 NC GND11 8 9 GND21 NC = NO CONNECT 2 AND PIN 8 ARE INTERNALLY CONNECTED. EITHER OR BOTH MAY BE USED FOR GND1. PIN 9 AND PIN 15 ARE INTERNALLY CONNECTED. EITHER OR BOTH MAY BE USED FOR GND2. 04736-002 1 PIN Figure 2. Pin Configuration Table 8. Pin Function Descriptions Pin No.
PAGE 9
ADM2483 TEST CIRCUITS VCC A R RL 0V OR 3V 04736-003 VOC R S2 S1 DE 04736-006 VOD CL VOUT B DE IN Figure 6. Driver Enable/Disable Figure 3. Driver Voltage Measurement 375Ω A B 375Ω VOUT RE CL Figure 4. Driver Voltage Measurement Figure 7. Receiver Propagation Delay VCC +1.5V S1 A CL1 S2 CL2 CL VOUT 04736-005 B RL –1.5V RE RLDIFF RE IN Figure 5. Driver Propagation Delay Figure 8. Receiver Enable/Disable Rev.
PAGE 10
ADM2483 SWITCHING CHARACTERISTICS VDD1 0.7VDD1 0.5VDD1 0.5VDD1 DE 0V tPLH B 0.5VDD1 0.5VDD1 tPHL 0.3VDD1 tZL 1/2VO tLZ VO 2.3V A, B A VOL + 0.5V tSKEW = |tPLH – tPHL| VOL tZH 90% POINT 90% POINT tHZ VOH A, B 10% POINT 10% POINT tR 2.3V 04736-009 VOL VOH – 0.5V A, B tF 0V Figure 9. Driver Propagation Delay, Rise/Fall Timing 04736-011 VOH Figure 11. Driver Enable/Disable Timing 0.7VDD1 RE 0.5VDD1 0.5VDD1 0.3VDD1 0V 0V tPLH tPHL tZL tLZ 1.5V RxD VOL + 0.
PAGE 11
ADM2483 TYPICAL PERFORMANCE CHARACTERISTICS 0.32 1.6 IDD1_RCVR_ENABLE @ 5.5V 0.30 1.2 OUTPUT VOLTAGE (V) SUPPLY CURRENT (mA) 1.4 1.0 0.8 IDD2_DE_ENABLE @ 5.5V 0.6 0.28 0.26 0.24 0.4 04736-038 0 –40 25 TEMPERATURE (°C) 0.20 –40 85 –25 –10 5 20 35 TEMPERATURE (°C) 50 65 80 Figure 16. Receiver Output Low Voltage vs. Temperature, I = –4mA Figure 13. Unloaded Supply Current vs. Temperature 120 4.78 100 4.76 OUTPUT VOLTAGE (V) 80 60 40 20 4.74 4.72 4.70 04736-014 4.68 0 0 0.
PAGE 12
ADM2483 460 tP_BLH @ VDD1 = VDD2 = 5.0V 440 1 tP_AHL @ VDD1 = VDD2 = 5.0V TIME (ns) 420 400 tP_BHL @ VDD1 = VDD2 = 5.0V 380 tP_ALH @ VDD1 = VDD2 = 5.0V 04736-034 340 –40 25 TEMPERATURE (°C) 4 CH1 5.00V CH3 1.00V 85 Figure 19. Driver Propagation Delay vs. Temperature 800 04736-022 2 360 CH2 1.00V CH4 5.00V M200ns A CH1 T 1.33600µs 3.10V Figure 21. Driver/Receiver Propagation Delay High to Low RCVR PROP HL/VDD1 = VDD2 = 5.0V 700 1 600 RCVR PROP LH/VDD1 = VDD2 = 5.
PAGE 13
35 300 30 OUTPUT CURRENT (mA) 350 250 BUS SIDE 200 150 LOGIC SIDE 100 0 0 50 100 150 CASE TEMPERATURE (°C) –15 –20 –25 04736-036 OUTPUT CURRENT (mA) –10 3.6 3.8 4.0 4.2 4.4 OUTPUT VOLTAGE (V) 4.6 4.8 10 0 –5 3.4 15 0 200 0 3.2 20 5 Figure 23. Thermal Derating Curve, Dependence of Safety-Limiting Values with Case Temperature per VDE 0884 –30 3.0 25 04736-037 50 04736-024 SAFETY-LIMITING CURRENT (mA) ADM2483 5.0 Figure 24. Output Current vs.
PAGE 14
ADM2483 CIRCUIT DESCRIPTION ELECTRICAL ISOLATION iCoupler Technology In the ADM2483, 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 26). Driver input and data enable signals, applied to the TxD and DE pins, respectively, and referenced to logic ground (GND1), are coupled across an isolation barrier to appear at the transceiver section referenced to isolated ground (GND2).
PAGE 15
ADM2483 TRUTH TABLES THERMAL SHUTDOWN The following truth tables use these abbreviations: The ADM2483 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. The thermal sensing circuitry detects the increase in die temperature under this condition and disables the driver outputs.
PAGE 16
ADM2483 10.000 1.000 0.100 DISTANCE = 5mm 10.00 DISTANCE = 100mm 1.00 0.10 0.01 1k 04736-027 0.010 0.001 1k DISTANCE = 1m 100.00 10k 100k 1M 10M MAGNETIC FIELD FREQUENCY (Hz) 100M Figure 27. Maximum Allowable External Magnetic Flux Density For example, at a magnetic field frequency of 1 MHz, the maximum allowable magnetic field of 0.2 kGauss induces a voltage of 0.25 V at the receiving coil. This is about 50% of the sensing threshold and does not cause a faulty output transition.
PAGE 17
ADM2483 APPLICATIONS INFORMATION POWER_VALID INPUT ISOLATED POWER SUPPLY CIRCUIT To avoid chatter on the A and B outputs caused by slow powerup and power-down transients on VDD1 (>100 µs/V), the ADM2483 features a power_valid (PV) digital input. This pin should be driven low until VDD1 exceeds 2.0 V. When VDD1 is greater than 2.0 V, the pin should be driven high. Conversely, upon power-down, the PV should be driven low before VDD1 reaches 2.0 V.
PAGE 18
ADM2483 OUTLINE DIMENSIONS 10.50 (0.4134) 10.10 (0.3976) 9 16 7.60 (0.2992) 7.40 (0.2913) 8 1 1.27 (0.0500) BSC 0.75 (0.0295) × 45° 0.25 (0.0098) 2.65 (0.1043) 2.35 (0.0925) 0.30 (0.0118) 0.10 (0.0039) COPLANARITY 0.10 10.65 (0.4193) 10.00 (0.3937) 0.51 (0.0201) 0.31 (0.0122) SEATING PLANE 8° 0.33 (0.0130) 0° 0.20 (0.0079) 1.27 (0.0500) 0.40 (0.
PAGE 19
ADM2483 NOTES Rev.