ADM2587EBRWZ IC

Technical Specifications of ADM2587EBRWZ

Datasheet	ADM2587EBRWZ datasheet
Category	Isolators
Family	Digital Isolators
Manufacturer	Analog Devices Inc.
Series	IsoPower?, iCoupler?
Packaging	Tube
Part Status	Active
Technology	Magnetic Coupling
Type	RS422, RS485
Isolated Power	Yes
Number of Channels	3
Inputs – Side 1/Side 2	2/1
Channel Type	Unidirectional
Voltage – Isolation	2500Vrms
Common Mode Transient Immunity (Min)	25kV/μs
Data Rate	500kbps
Propagation Delay tpLH / tpHL (Max)	–
Pulse Width Distortion (Max)	–
Rise / Fall Time (Typ)	1.1μs, 1.1μs (Max)
Voltage – Supply	3.3V, 5V
Operating Temperature	-40°C ~ 85°C
Package / Case	20-SOIC (0.295″, 7.50mm Width)
Supplier Device Package	20-SOIC

ADM2587EBRWZ-REEL7 Introduction

The ADM2587EBRWZ is a half-duplex, fully isolated RS-485 transceiver for industrial applications that must be very reliable and immune to noise. Its built-in isolated DC-DC converter keeps the bus and logic interfaces from each other. This makes it a good choice for harsh industrial situations.

Circuit Description

● Signal Isolation

The ADM2582E and ADM87E chips are kept separate by the logic side of the connection. The part has a digital isolation and transceiver section that separates incoming signals. Through an isolation barrier, data sent to the TxD and DE pins and referenced to logic ground is sent to the transceiver section, which is referenced to isolated ground (GND2). The isolation barrier connects the RXD pin, the output of a single-ended receiver, to the logic ground. Transceiver part.

● Power Isolation

An isoPower isolated dc-to-dc converter isolates power in the ADM2582E/ADM2587E. Modern power supply work like the ADM2582E/dc-to-dc ADM2587E converter. PWM feedback is used in the secondary side controller architecture. An oscillating circuit switches VCC power into a chip-scale air-core transformer.

The secondary side receives inverted 3.3 V power. Secondary (VISO) controllers control output. A dedicated iCoupler data channel sends a PWM control signal to the primary (VCC) side. PWM controls secondary side power via the oscillator circuit. Feedback boosts power and efficiency.

● Thermal Shutdown

The thermal shutdown circuitry in the ADM2582E/ADM2587E keeps the parts from using too much power when there is a problem. High driver currents can be caused by shorting the driver outputs to a source with a low impedance. When this happens, the thermal sensing circuitry notices the rise in die temperature and turns off the driver outputs. When a die temperature of 150°C is reached, this circuitry is set up to turn off the driver outputs. At 140°C, the drivers are turned back on as the device cools down.

● Open- And Short-Circuit, Fail-Safe Receiver Inputs

Fail-safe features keep receiver output high when receiver inputs are open or shorted. The receiver input’s termination resistance voltage drops to 0 V when the bus is idle. Due to receiver input thresholds, traditional transceivers require external bias resistors on the A and B pins to maintain receiver outputs between 200 and +200 mV. The short-circuit, fail-safe receiver input eliminates bias resistors by adjusting the threshold between 30 and 200 mV. The receiver output is always high when the A-B voltage drops to 0 V due to the assured negative threshold.

● DC Correctness and Magnetic Field Immunity

Digital signals cross the isolation barrier using iCoupler. Chip-scale transformer windings convey digital signals across the barrier via a magnetic field. Digital inputs become transformer primary winding excitation waveforms. The secondary winding converts the induced waveforms back to binary. When the isolator input changes logic, the transformer sends a 1 ns pulse to the decoder.

Pulses can set or reset the decoder; therefore, the input’s logic transitions can also. To ensure dc output, refresh pulses showing the right input state are supplied at regular intervals if there are no logic changes at the input for more than 1 s. The input side is unpowered if the decoder doesn’t obtain internal pulses for longer than 5 s. The watchdog timer circuit resets the isolator output. The ADM2582E/ADM2587E devices should only turn on and off.

The transformer receiving coil’s generated voltage limits the ADM2582E/magnetic ADM87E’s field immunity. The next section details the prerequisites for this. The ADM2582E/most ADM2587E’s vulnerable operating mode is 3.3 V. Transformer output pulses are >1.0 V. A 0.5 V sensing threshold in the decoder allows generated voltages to be tolerated.

● Applications Information PCB Layout and Electromagnetic Interference (EMI)

ADM2582E/ADM2587E isolated RS-422/RS-485 transceivers include an isoPower dc-to-dc converter. Logic interfaces don’t need external interface equipment. The input and output supply pins need a power supply bypass. The power supply chip-scale transformers of the ADM2582E/ADM2587E use 180 MHz oscillators to transport power effectively. When it operates properly, the iCoupler data section transmits switching transients to the power supply pins.

Bypass capacitors are needed for multiple frequencies. Ripple suppression and correct regulation require big capacitors, while noise suppression requires low inductance and high frequency. Pin 1 (GND1) is linked to Pin 2 (VCC) and Pin 8 (VCC) to Pin 9 (GND1) for VCC. The pins 11, 12, 19, and 20 on GND2 connect the VISOIN and VISOOUT capacitors to it. (GND2). Putting two capacitors in parallel can reduce noise and ripple.

0.1 F and 10 F capacitors are recommended for VISOOUT and VCC, respectively. For VISION at Pins 19 and 20 and VCC at Pins 1 and 2, use 0.01 F and 0.1 F ceramic capacitors. The wires from each capacitor end to the power supply pin should not exceed 10 mm. The ADM2582E/ADM2587E components’ dc-to-dc converter must operate at high frequency to efficiently transmit power from small transformers. High-frequency currents propagate throughout a circuit board’s ground and power planes, creating edge and dipole radiation.

ADM2582E/ADM2587E buses have an internal split paddle and lead frame. Filter high-frequency currents on the GND2 pins (Pin 11 and Pin 14) and VISOOUT signal of the integrated dc-to-dc converter for optimal noise reduction. Use surface-mount ferrite beads in series with signals before sending them back to the device.

● Insulation Lifetime

When voltage stress is put on an insulation structure for a long enough time, it will eventually break down. How the voltage waveform looks when applied across the insulation affects how fast the insulation breaks down. Analog Devices uses a long list of tests to figure out how long the insulation structure in the ADM2582E/ADM2587E will last. Voltage levels higher than the rated continuous working voltage are used in accelerated life testing. Acceleration factors are found for different operating conditions. This lets the time to failure at the working voltage of interest be calculated.

Conclusion

In conclusion, the ADM2587EBRWZ is a highly reliable and robust RS-485 transceiver that is perfect for industrial applications requiring high noise immunity and reliability levels. It is a great choice for industrial applications because it has features like high isolation voltage, ESD protection, high-speed operation, low power consumption, and half-duplex operation.

When designing a circuit with the ADM2587EBRWZ, it’s important to consider things like the power supply requirements, the termination, the layout, and ESD protection to ensure the circuit works well and reliably. At ICRFQ, we have affordable prices on high-quality electronic parts like the ADM2587EBRWZ. So, please don’t hesitate to contact us if you have any questions or want to place an order. We’re here to help all the time.

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