PC817 4-Channel Optocoupler Isolation Module

PC817 4-Channel Optocoupler Isolation Module provides a reliable, efficient solution for achieving galvanic isolation between two different voltage level systems, typically separating low-voltage control circuits from high-voltage or noisy power circuits. This module integrates four independent channels, each featuring the popular Sharp PC817 optoisolator IC. Each channel utilizes an input LED to trigger an output phototransistor without any electrical connection, effectively breaking ground loops and preventing voltage spikes from damaging sensitive electronics like microcontrollers. Consequently, engineers use this module extensively to eliminate noise and level shift signals between 3.3 V and 5 V logic domains or to interface high-voltage DC components. Therefore, the PC817 module is an indispensable tool for protecting and stabilizing your electronic designs.

Key Features:

• Four Independent Channels: Integrates four separate PC817 channels onto a single board, allowing for simultaneous isolation of up to four digital or analog signals.
• High Isolation Voltage: Offers excellent electrical isolation, typically rated up to 5000 V_RMS, preventing damaging voltage surges from crossing the barrier.
• Flexible Voltage Compatibility: Easily isolates signals and shifts logic levels between different operating voltages, commonly supporting both 3.3 V and 5 V systems.
• Low Current Transfer Ratio (CTR) Variation: The PC817 series provides consistent and predictable signal transfer across the isolation barrier.
• Simplified Interfacing: The module includes onboard current-limiting resistors for the input LEDs and pull-up resistors for the output, simplifying wiring.

Technical Specifications:

• Number of Channels: 4
• Optocoupler IC: PC817 (SHARP) or functional equivalent
• Maximum Collector-Emitter Voltage (V_CEO): 35 V
• Maximum Collector Current (I_C): 50 mA
• Input LED Forward Voltage (V_F): ≈ 1.2 V (Typically 1.1 V to 1.4 V)
• Isolation Voltage (V_ISO): 5000 V_RMS minimum
• Operating Temperature Range: −30°C to +100°C

Mechanical Specifications:

• Package Type (IC): DIP-4 (used for individual ICs on the module)
• Module Dimensions: Small form factor PCB module
• Mounting: Pin headers for breadboard or through-hole mounting via jumper wires.
• Input Side Terminals: Screw terminals or standard pin headers.

Dimensions:

• Module Length: ≈ 38 mm
• Module Width: ≈ 25 mm
• Mounting Hole Diameter: Standard ≈ 3 mm (If included)
• Weight: Extremely lightweight, typically < 10 g.

Pinout and Wiring:

• VCC (Output Side): Connect the module’s high-voltage supply (e.g., 5V or 12V) for the phototransistors.
• GND (Shared): Connect to the common ground for both the input and output sides.
• IN1, IN2, IN3, IN4: Digital input pins (Anode of the LED). Connect these to the output pins of the controlling MCU (e.g., 3.3 V logic).
• OUT1, OUT2, OUT3, OUT4: Digital output pins (Collector of the phototransistor). Connect these to the input pins of the receiving circuit (e.g., 5 V logic).

Datasheet Reference:

• Download PC817 Optocoupler Datasheet

Commonly Used in:

• Microcontroller Projects: Essential for connecting low-voltage microcontrollers (like Arduino, ESP32) to higher voltage peripherals.
• Industrial Control Systems: Providing necessary isolation in PLCs and motor control circuits where noise is prevalent.
• Signal Level Shifting: Used frequently for safely translating 3.3 V logic signals to 5 V logic, furthermore, simplifying multi-voltage board integration.

Applications:

• Ground Loop Elimination: Breaking unintended electrical paths between different parts of a system that can cause noise and instability.
• Relay and Motor Drivers: Safely isolating the control signal from the high-current switching circuit.
• High-Side/Low-Side Switching: Providing isolated gate drive signals for power MOSFETs and IGBTs.
• Battery Monitoring Systems: Protecting the measuring circuit from high battery voltages.

Equivalent Models:

• 4N35 / 4N25 Optocouplers: Single-channel alternatives often used in similar applications, however, the PC817 module integrates four channels.
• TLP521 (Toshiba): A functionally equivalent single-channel optocoupler often found in similar modules, offering comparable performance characteristics.
• CNY74-4: A specific quad-channel optocoupler package providing similar four-channel isolation on a single IC.

Package Includes:

• 1 x PC817 4-Channel Optocoupler Isolation Module