EL817(B)

Overview

The EL817(B) is a single-channel transistor output optocoupler manufactured by Everlight Electronics. It features an infrared emitting diode optically coupled to an NPN phototransistor in a compact DIP-4 package. Key electrical parameters include a maximum collector-emitter voltage of 35 V, a maximum forward current of 60 mA, and a typical current transfer ratio ranging from 50% to 600% at 5 mA. The device provides high isolation with a rated insulation voltage of 5000 Vrms. Operating temperature ranges from -55 °C to +110 °C.

Feature Summary

• High isolation voltage capability between input and output circuits
• Compact dual-in-line package design for space-constrained applications
• RoHS compliant and halogen-free construction
• Recognized by UL, VDE, SEMKO, and other international safety agencies

Applications

• Signal transmission between circuits of different potentials and impedances
• Programmable logic controllers (PLCs)
• Telecommunication equipment interfaces
• Home appliances such as fan heaters

Procurement Notes

Verify the specific suffix designation when ordering, as variations exist within the EL817 family. Confirm compliance requirements such as RoHS status and lead spacing options (standard vs. wide lead). Ensure the selected variant matches the required current transfer ratio bin if precise gain characteristics are critical for the circuit design.

Selection Notes

Select this component for applications requiring galvanic isolation with digital signal transmission. Consider the CTR range when designing biasing networks to ensure reliable switching across the full operating temperature range. Verify that the package type meets the PCB layout constraints and that the isolation voltage rating exceeds the system's peak transient requirements.

Part Context

This part belongs to the EL817 series of photocouplers, which are widely used general-purpose isolators. The series includes various packaging options and lead configurations to suit through-hole and surface-mount assembly needs. It serves as a standard interface component for isolating control signals from power stages in industrial and consumer electronics.

Replacement Considerations

Direct replacements may include other EL817 variants from Everlight or equivalent transistor-output optocouplers from other manufacturers, provided pinout, isolation voltage, and CTR specifications match. Verify mechanical dimensions and certification approvals before substitution.