The EL357 is a series of single-channel phototransistor optocouplers manufactured by Everlight Electronics Co Ltd. These optocouplers consist of an infrared light-emitting diode (LED) optically coupled to a phototransistor. They are designed for applications requiring electrical isolation between input and output circuits.

Applications

• Power supplies: Providing feedback isolation in switching power supplies.
• Industrial control systems: Isolating control signals from high-voltage or noisy environments.
• Digital logic inputs: Interfacing digital logic circuits with different voltage levels or ground potentials.
• Microcontroller input isolation: Protecting microcontroller inputs from voltage spikes or overcurrent conditions.
• Telecommunications equipment: Isolating telephone lines from sensitive electronic circuits.

Features

• High isolation voltage: Provides electrical isolation up to several kilovolts.
• Compact package: Available in a DIP-4 package, suitable for through-hole mounting.
• Current Transfer Ratio (CTR): Offers a range of CTR options to suit different application requirements.
• Low saturation voltage: Ensures efficient signal transfer with minimal voltage drop.
• Fast switching speed: Enables high-speed data transmission.
• RoHS compliant: Meets environmental standards for hazardous substance restrictions.

Benefits

• Electrical isolation: Protects sensitive circuits from voltage transients and ground loops.
• Noise immunity: Reduces the effects of electrical noise on signal integrity.
• Simplified circuit design: Allows for easy interfacing between circuits with different voltage levels.
• Increased system reliability: Improves system robustness by isolating potential fault sources.
• Enhanced safety: Provides a safety barrier between high-voltage and low-voltage circuits.

Additional Details

The EL357 series is available in various CTR (Current Transfer Ratio) grades, allowing designers to select the optimal device for their specific application. The CTR is the ratio of the collector current to the forward current of the LED. The device operates over a wide temperature range, typically from -30°C to +110°C, ensuring reliable performance in harsh environments. The input forward voltage is typically around 1.2V, and the collector-emitter breakdown voltage is typically 80V. The isolation voltage is rated at 5000Vrms. Different package options might exist, so consult the datasheet for specific dimensions and pinout details.