EL817 / PC817 Optocoupler — SOP-4 SMD, 5kV Isolation, 50–300% CTR (20-Pack)

EL817 / PC817 Optocoupler — SOP-4 SMD, 5kV Isolation

The EL817 (also known as PC817) is a general-purpose phototransistor optocoupler in a compact SOP-4 SMD package. With 5,000V RMS isolation voltage and a current transfer ratio (CTR) of 50–300%, it is the go-to choice for galvanic isolation in switching power supplies, industrial I/O interfaces, and microcontroller signal coupling.

Key Specifications

Parameter	Value
Package	SOP-4 (SMD)
Isolation Voltage	5,000V RMS
CTR (IF=5mA)	50–300%
Output Collector Voltage (VCEO)	35V
Forward Current (IF)	50mA max
Operating Temperature	-30°C to +100°C
Quantity	20 pieces

Why Choose EL817 SOP-4 SMD?

• SMD form factor — ideal for compact PCB designs where DIP packages are too large
• 5kV isolation — meets safety requirements for mains-connected circuits
• Wide CTR range — flexible for both linear and switching applications
• Drop-in compatible with PC817, LTV817, and 4N35 in SOP-4 footprint
• 20-pack value — enough for prototyping and small production runs

Typical Applications

• SMPS feedback isolation (flyback, LLC converters)
• PLC digital I/O signal isolation
• Microcontroller to relay driver isolation
• AC zero-crossing detection circuits
• RS-232 / RS-485 signal isolation

Package Contents

• 20× EL817 / PC817 Optocoupler (SOP-4 SMD)

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