Isolation Transformer/Optocoupler

Product Specifications

Technical details and manufacturing context for Isolation Transformer/Optocoupler

Definition

This component is a critical part of Communication Interface Circuits, designed to prevent ground loops, block high-voltage transients, and isolate different voltage domains while maintaining signal integrity for data transmission between systems. It is available in two primary forms: isolation transformers, which use magnetic coupling through a transformer core, and optocouplers, which use light-emitting diodes and photodetectors to transmit signals optically across an isolation barrier. Both types provide galvanic isolation, ensuring complete electrical separation between input and output circuits. The component is used in a wide range of applications, including industrial control systems, medical devices, and telecommunications equipment, where safety and noise immunity are paramount. Key parameters include isolation voltage (2500–5000 V AC), creepage distance (6–8 mm), clearance distance (5–6 mm), operating temperature (-40 to 85 °C), storage temperature (-55 to 125 °C), humidity (5–95% RH), input voltage range (3–30 V DC), output current (10–50 mA), isolation resistance (≥10^10 Ω), coupling capacitance (0.5–2 pF), propagation delay (0.1–10 µs), package type (DIP-8, SOP-8), and weight (0.5–2 g). These values are reference ranges and must be verified for the specific model and application. This directory entry references IEC 60747-5-5, IEC 60664-1, IEC 60068-2-1, IEC 60068-2-2, IEC 60068-2-78, and IEC 60250 for procurement and verification. IEC 60068-2-1 and IEC 60068-2-2 are cold and dry-heat test methods and do not establish the listed temperature ranges; product compliance must be confirmed for the specific model. Always confirm model-specific specifications and standards with the legal manufacturer or supplier before use.

Working Principle

Isolation transformers transfer signals or power through magnetic coupling, using a transformer core to provide galvanic isolation. Optocouplers use an LED to convert electrical signals into light, which is then detected by a phototransistor, achieving optical transmission across an isolation barrier. Both methods ensure complete electrical separation between input and output circuits, preventing ground loops and blocking high-voltage transients.

Common Materials

Ferrite Core, Copper Wire, LED Chip, Phototransistor, Epoxy Resin

Technical Parameters

Parameter	Typical range	Notes & selection driver
Isolation Voltage	2500–5000 V AC	Minimum for safety isolation in mains applications.IEC 60747-5-5
Creepage Distance	6–8 mm	Required for reinforced insulation in pollution degree 2.IEC 60664-1
Clearance Distance	5–6 mm	Ensures withstand voltage under transient overvoltages.IEC 60664-1
Operating Temperature	-40–85 °C	Extended range for industrial environments.
Storage Temperature	-55–125 °C	Survival range during shipping and storage.
Humidity	5–95 % RH	Non-condensing; condensation may reduce isolation.IEC 60068-2-78
Input Voltage Range	3–30 V DC	Compatible with standard logic levels.
Output Current	10–50 mA	Maximum continuous output current.
Isolation Resistance	≥10^10 Ω	Measured at 500 V DC.IEC 60250
Coupling Capacitance	0.5–2 pF	Lower is better for high-frequency noise rejection.
Propagation Delay	0.1–10 µs	Critical for high-speed digital isolation.
Package Type	DIP-8, SOP-8	Standard through-hole and surface-mount options.JEDEC MS-001
Weight	0.5–2 g	Affects pick-and-place and mechanical design.

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Components / BOM

Transformer Core Part
Provides magnetic coupling for signal/power transfer while maintaining isolation

Material: Ferrite
Primary/Secondary Windings Part
Copper wire coils that create and receive electromagnetic fields

Material: Copper
LED (for optocoupler) Part
Converts electrical signals to light signals

Material: Gallium Arsenide
Photodetector (for optocoupler) Part
Converts light signals back to electrical signals

Material: Silicon
Isolation Barrier
Physical separation layer that prevents electrical conduction

Material: Epoxy/Plastic

Applied To / Applications

This component is essential for the following industrial systems and equipment:

Communication Interface Circuit

View system integration details

Manufacturers of Isolation Transformer/Optocoupler

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Frequently Asked Questions

What is the difference between an isolation transformer and an optocoupler?

An isolation transformer uses magnetic coupling to transfer signals or power, while an optocoupler uses light to transmit signals across an isolation barrier. Both provide galvanic isolation, but optocouplers are typically used for digital signals, whereas transformers can handle higher power levels.

What isolation voltage is typical for mains applications?

Typical isolation voltage ranges from 2500 to 5000 V AC, as specified in the reference data. However, the exact value depends on the model and must be verified with the manufacturer for your specific application.

How do I choose between an isolation transformer and an optocoupler?

Consider the signal type, speed, and power requirements. Optocouplers are suitable for digital signals with moderate speeds, while transformers can handle higher power and are often used in power supplies. Also, check parameters like propagation delay and coupling capacitance.

What standards apply to these components?

Relevant standards include IEC 60747-5-5 for isolation voltage, IEC 60664-1 for creepage and clearance distances, and IEC 60068-2-1/2 for temperature testing. These standards serve as references; always confirm compliance with the manufacturer.

Data Basis

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current:	Up to 1A continuous (depends on model)
voltage:	Up to 5kV RMS isolation voltage (depends on model)
frequency:	DC to 100kHz (signal transfer capability)
temperature:	-40°C to +125°C (operating), -55°C to +150°C (storage)

Product Specifications

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