EL817(S1)(D)(TU)

Overview

The EL817(S1)(D)(TU) is a single-channel transistor output optocoupler manufactured by Everlight Electronics. It integrates an infrared emitting diode and an NPN phototransistor in a compact SMD-4 package to provide electrical isolation between input and output circuits. Key electrical specifications include a maximum collector-emitter voltage of 35V, a continuous collector current of 50mA, and a typical forward voltage of 1.2V at a maximum DC forward current of 60mA. The device offers a high isolation voltage of 5000Vrms and operates within a temperature range of -55°C to +110°C.

Feature Summary

• Provides galvanic isolation via optical coupling between input LED and output phototransistor
• High insulation strength with 5000Vrms isolation voltage rating
• Compact surface-mount design suitable for automated assembly

Applications

• Digital logic signal transmission and level shifting
• Power supply control and switching circuits
• Electrical isolation between systems and circuits
• Impedance transformation in electronic interfaces

Procurement Notes

Verify the specific suffix (e.g., TU vs TF) against the datasheet to confirm reel packaging quantities and tape-and-reel specifications. Ensure the ordering code matches the required CTR binning if strict transfer ratio limits are necessary for the application. Confirm RoHS compliance status through official manufacturer documentation prior to procurement.

Selection Notes

Select this component when a small form-factor solution is required for isolating low-voltage digital signals from higher voltage loads. The 50mA output current capability supports direct driving of many logic inputs or relay coils. Consider thermal management requirements given the wide operating temperature range and ensure the PCB layout accommodates the creepage distances mandated by the 5000Vrms isolation rating.

Part Context

This part belongs to the EL817 family of optocouplers, which are widely used for general-purpose isolation. The S1 designation typically indicates specific performance characteristics such as Current Transfer Ratio (CTR) bins compared to standard variants. The TU suffix denotes the surface-mount package type, distinguishing it from through-hole DIP versions like the standard EL817.

Replacement Considerations

Direct pin-compatible replacements may include other EL817 series variants from Everlight or competitors offering similar 4-SMD transistor output optocouplers. Verify that substitute parts meet the 5000Vrms isolation requirement and match the 35V/50mA output ratings. Check CTR ranges to ensure compatibility with existing drive circuitry.