MCT2E Phototransistor Optocoupler IC DIP-6

MCT2E Phototransistor Optocoupler IC DIP-6 is a widely recognized component that provides essential galvanic isolation between low-voltage control circuitry and higher-voltage or noisy output loads. This optocoupler features an infrared Light Emitting Diode (LED) on the input side, optically coupled to an NPN phototransistor on the output side. Consequently, the MCT2E effectively prevents ground loops and voltage spikes from propagating between separate sections of a circuit, offering superior noise immunity and protecting sensitive logic components. The device switches the output transistor into saturation when current flows through the input LED, making it ideal for digital signal transfer and general-purpose switching applications. Therefore, designers rely on the MCT2E to ensure maximum safety and reliability in critical interface designs.

Key Features:

• High Isolation Voltage: Provides a guaranteed electrical isolation rating of up to 5000 V_RMS (typically 5300 V_RMS), which is essential for meeting regulatory safety standards.
• Phototransistor Output: The output features a three-terminal phototransistor (Collector, Emitter, Base), allowing external access to the base pin for speed or sensitivity adjustments.
• High Current Transfer Ratio (CTR): Guarantees a minimum CTR of 20% (I_C/I_F) at the specified operating conditions, ensuring efficient signal transfer.
• Versatile Compatibility: The input LED is compatible with standard low-voltage logic levels (TTL, CMOS), enabling direct interfacing with most microcontrollers.
• Standard DIP Package: The ubiquitous 6-pin Dual In-line Package (DIP) ensures easy through-hole mounting and broad compatibility across different assembly platforms.

Technical Specifications:

• Isolation Voltage (V_ISO): 5000 V_RMS minimum (1 minute)
• Collector-Emitter Voltage (V_CEO): 30 V minimum
• Collector Current (I_C): 50 mA maximum
• Input LED Forward Voltage (V_F): Typically 1.15 V (≤ 1.5 V max)
• Current Transfer Ratio (CTR): 20% minimum (I_F = 10 mA, V_CE = 10 V)
• Bandwidth (f_c): ≈ 80 kHz (Allows for moderate speed digital signaling)
• Operating Temperature Range: −55°C to +100°C

Mechanical Specifications:

• Package Type: DIP-6 (Through-Hole)
• Mounting: Through-Hole Technology (THT)
• Case Material: Black Epoxy Resin (UL 94 V-0 Flammability Rated)

Dimensions:

• Body Length: ≈ 6.9 mm
• Body Width: ≈ 6.5 mm
• Pin Pitch (Between pins): 2.54 mm (0.1 inch)
• Row Spacing (Between rows): 7.62 mm (0.3 inch)
• Total Height: ≈ 3.5 mm (Seated height)

Pinout and Wiring:

• Pin 1 (Anode): Connect to the positive supply (V_CC) of the control circuit via a current-limiting resistor (R_limit).
• Pin 2 (Cathode): Connect to the microcontroller’s digital output pin or ground (GND) to activate the LED.
• Pin 3 (No Connection): This pin is internally unconnected and serves to maximize the creepage distance for isolation.
• Pin 4 (Emitter): Connect the transistor’s emitter to the load return path or ground on the output side.
• Pin 5 (Collector): Connect the transistor’s collector to the load or the positive supply (V_CC) of the isolated output side.
• Pin 6 (Base): Optional connection; you can connect a high-value resistor from Base to Emitter to stabilize the transistor or use it to externally bias the transistor.

Datasheet Reference:

• Download ON Semiconductor MCT2E Datasheet

Commonly Used in:

• Switching Power Supplies (SMPS): Providing feedback isolation between the primary and secondary sides for voltage regulation.
• Microcontroller Input Interfaces: Safely isolating sensitive microcontroller inputs from noisy field signals or high-voltage sensors.
• Digital Signal Isolation: Used in data transmission lines to prevent common-mode noise corruption.

Applications:

• Digital Logic Coupling: Transferring logic state information between two independent power domains.
• Noise Suppression: Eliminating ground loops between separated circuit boards or systems.
• Relay and Solenoid Driving: Providing an isolated interface to switch larger loads using an external driver stage.
• AC/DC Detection: Converting AC or high-voltage DC input status into an isolated low-voltage digital signal.

Equivalent Models:

• 4N25 / 4N35: These are very common general-purpose phototransistor optocouplers, often used as direct, though sometimes lower-spec, substitutes for the MCT2E.
• PC817 (Sharp): Another popular single-transistor output optocoupler, however, it comes in a different, often smaller, 4-pin package without the base pin exposed.
• LTV-817 (Lite-On): A widely available functional equivalent to the PC817, providing basic signal isolation characteristics.

Package Includes:

• 1 x MCT2E Phototransistor Optocoupler IC DIP-6