PC817 2-Channel Optocoupler Isolation Module

PC817 2-Channel Optocoupler Isolation Module is an essential component for safely interfacing circuits operating at different voltage levels or with distinct ground potentials. This module integrates two independent PC817 optocoupler ICs, offering dual-channel optical isolation between a low-voltage control side (like a microcontroller) and a high-voltage, noisy, or sensitive load side. The internal structure uses an infrared LED to transmit a signal across a non-conductive gap to a phototransistor. Therefore, the module achieves effective electrical separation and noise immunity. Furthermore, the simple interface and robust isolation capability make this module indispensable for protecting sensitive digital electronics from high-voltage spikes, ground loops, and transient noise found in industrial or power applications.

Key Features:

• Dual Channel Isolation: Features two independent PC817 optocouplers, allowing simultaneous isolation of two separate signal lines.
• High Isolation Voltage: Provides isolation up to 5000 V_RMS, offering superior protection against electrical hazards and common mode noise.
• Logic Level Conversion: Easily interfaces 3.3 V or 5 V microcontrollers with systems running at higher or different voltages.
• High Current Transfer Ratio (CTR): The PC817 series typically offers a wide CTR range, ensuring reliable signal transfer even with low input drive current.
• Fast Switching Speed: Achieves typical rise and fall times (t_r and t_f) suitable for most non-high-speed digital and analog signal isolation tasks.

Technical Specifications:

• Optocoupler IC: 2 x SHARP PC817 (or equivalent)
• Number of Channels: 2
• Isolation Voltage (V_ISO): 5000 V_RMS minimum
• Collector-Emitter Voltage (V_CEO): 35 V maximum
• Collector Current (I_C): 50 mA maximum (Per channel)
• Input Forward Current (I_F): 50 mA maximum (Per channel)
• Operating Temperature Range: −30°C to +100°C

Mechanical Specifications:

• Module Board Dimensions: Compact and PCB-friendly design.
• Mounting: Includes mounting holes for fixed installation in enclosures.
• Connectors: Screw terminals for easy and secure wiring of input/output signals.

Dimensions:

• Board Length: ≈ 38 mm
• Board Width: ≈ 25 mm
• Mounting Hole Diameter: ≈ 3 mm
• Weight: ≈ 8 g

Pinout and Wiring:

• VCC (Input): Power supply for the input side (LED drive circuit), typically 3.3V or 5V.
• GND (Input): Ground reference for the input side.
• IN1 / IN2: Digital input pins. Drive these pins LOW to turn the respective channel’s LED ON (requires pull-up resistor).
• VCC (Output): Power supply for the output side (phototransistor collector), typically the voltage of the isolated circuit (up to 35V).
• GND (Output): Ground reference for the output side. This ground is isolated from the input side GND.
• OUT1 / OUT2: Digital output pins. These pins connect to the collector of the phototransistor and require an external pull-up resistor to the VCC (Output) rail. They output LOW when the input LED is ON.
• Wiring Note: Always ensure you use the appropriate pull-up resistors on both the input side (if driving directly from logic) and the output side (for collector signal reading).

Datasheet Reference:

• Download Vishay PC817 Optocoupler Datasheet

Commonly Used in:

• Microcontroller Projects: Protecting sensitive microcontrollers from high-voltage motor drivers, AC relays, or industrial sensors.
• Level Shifting: Converting signal levels between 3.3V and 5V circuits where complete electrical isolation is mandatory.
• Industrial Control Systems: Isolating PLC I/O lines from field devices to prevent noise and damage.

Applications:

• Noise Suppression: Eliminating ground loop currents and transient spikes between interconnected electronic devices.
• Power Supply Monitoring: Providing isolated feedback signals regarding power rail status.
• Motor Drive Interface: Safely sending digital control signals to gate drivers or power switching circuits.
• High-Side/Low-Side Switching: Controlling large voltage switches from low-voltage logic without direct electrical connection.

Equivalent Models:

• EL817 / LTV-817: These are functionally identical single-channel optocouplers. Consequently, a module based on them offers the same isolation characteristics.
• CNY74-2: A widely recognized dual-channel optocoupler, offering a direct functional replacement for the dual-channel PC817 configuration.
• TCMT1100: Another common photo-transistor optocoupler used in similar isolation and level-shifting applications.

Package Includes:

• 1 x PC817 2-Channel Optocoupler Isolation Module