MOC3021 Optocoupler Traic Driver IC DIP-6

MOC3021 Optocoupler with Triac Driver is an essential component for engineers and hobbyists who need to control high-voltage AC loads from low-voltage digital circuits, like microcontrollers. This device achieves perfect isolation by using an infrared LED to optically activate an integrated silicon bidirectional switch (a triac driver). Crucially, the MOC3021 is a non-zero crossing optocoupler, meaning it triggers the external triac immediately upon receiving the control signal, regardless of where the AC sine wave is in its cycle. This feature makes it ideal for phase control applications, such as dimmer circuits and motor speed controllers, where you must precisely control the power delivered to the load. Use the MOC3021 to safely and effectively bridge the gap between sensitive logic and robust power lines.

Key Features:

• Non-Zero Crossing Triac Driver: It immediately triggers the output triac at any point in the AC cycle, giving you full control for phase-angle dimming and speed control.
• High Isolation Voltage: Provides excellent electrical isolation between the low-voltage input and the high-voltage output, typically rated for 5000 Vrms.
• Infrared LED Input: The input side uses a standard LED that a microcontroller or logic gate can easily drive.
• Triac Driver Output: The output circuit is designed to drive the gate of a larger, external power triac that can handle the full load current.
• Low Input Trigger Current: Requires only a small current to activate the internal LED, simplifying integration with CMOS and TTL logic.
• Standard DIP-6 Package: The common, through-hole package makes it easy to prototype on breadboards or solder onto PCBs.

Technical Specifications:

• Output Device: Phototriac Driver (Non-Zero Crossing)
• Maximum Off-State Voltage (V_DRM): 400V (Suitable for 120 Vrms AC mains)
• Input LED Forward Voltage (V_F): Typically 1.15V (at 10mA)
• Input LED Trigger Current (I_FT): Maximum 15 mA
• Output On-State Current (I_TM): Maximum 100 mA (peak)
• Isolation Voltage: 5000 Vrms (Minimum)
• Package Type: DIP-6

Mechanical Specifications:

• Pin Count: 6 Pins
• Mounting: Through-Hole (DIP)
• Material: Plastic molded package.

Dimensions:

• Length (Body): ~7.1 mm
• Width (Body): ~6.5 mm
• Pin Pitch (Spacing between pins): 2.54 mm (0.1 in)
• Row Spacing: ~7.62 mm (0.3 in)

Pinout and Wiring:

• Pin 1 (Anode): Connect the positive side of the control signal (from microcontroller/logic).
• Pin 2 (Cathode): Connect the negative side of the control signal and ground.
• Pin 3 (No Connection): Leave this pin floating.
• Pin 4 (MT1/Cathode): Connect to one side of the AC line and the main terminal 1 of the power triac.
• Pin 6 (MT2/Anode): Connect to the gate of the external power triac.
• Pin 5 (No Connection): Leave this pin floating (Though typically, DIP-6 optocouplers leave Pin 5 unconnected for mechanical stability, Pin 6 is the Triac output. Please refer to the specific datasheet for the pin 4 and 6 connection in your product’s breakout board).
• Wiring Note: Always use a current-limiting resistor in series with the LED input (Pin 1) to protect the LED. Connect the output pins (4 and 6) to the gate and MT1 of an external power triac to switch the high-voltage load.

Datasheet Reference:

• Download Datasheet

Commonly Used in:

• Lighting Control: Essential for building AC light dimmers and soft-start lighting systems.
• Motor Control: Used to implement variable speed control for universal AC motors.
• Solid State Relays (SSRs): Forms the core isolation and driver stage of a simple, custom-built solid-state relay.

Applications:

• AC Dimmer Circuits: Precisely control the brightness of incandescent or compatible LED lights.
• Microcontroller-Controlled AC Switching: Safely switch on/off high-power appliances and solenoid valves.
• Industrial Controls: Provide isolated interfaces between sensitive PLC (Programmable Logic Controller) outputs and high-voltage machinery.

Equivalent Models:

• MOC3023: A lower-sensitivity version, requiring 5 mA more current to trigger.
• MOC3041/MOC3061 (Zero-Crossing): These are alternatives if you specifically need a zero-crossing function for resistive loads (like switching heaters), which minimizes electrical noise.

Package Includes:

• 1 x MOC3021 Optocoupler Triac Driver IC DIP-6