Technical Summary: CNY75 Optocoupler

CNY75 Optocoupler Technical Summary

Overview

The CNY75(G) Series is a high-performance optocoupler family consisting of a gallium arsenide infrared emitting diode optically coupled to a phototransistor. Designed for reliable signal isolation in demanding applications, this component provides electrical isolation between input and output circuits while transmitting analog or digital signals. The series meets stringent international safety standards for reinforced insulation applications.

Key advantages of the CNY75 include its high isolation voltage rating, stable current transfer ratio (CTR), and robust construction suitable for industrial environments. The special construction results in exceptionally low coupling capacitance, making it suitable for noise-sensitive applications.

Features

High isolation voltage rating: 600V_RMS (848V peak)
Rated impulse voltage (transient overvoltage) V_IOTM = 6kV peak
Isolation test voltage (partial discharge test voltage) V_pd = 1.6kV
Rated recurring peak voltage (repetitive) V_IORM = 600V_RMS
Excellent creeping current resistance: CTI = 275 (Comparative Tracking Index)
Minimum thickness through insulation ≥ 0.75mm
Current Transfer Ratio (CTR) offered in 3 selectable groups
Flame-retardant isolation materials (UL94-V0 rating)
Extra low coupling capacitance (typical 0.3pF)
Pollution degree 2 classification (per DIN/VDE 0110 and IEC 664)
Climatic classification: 55/100/21 (IEC 68 part 1)
Comprehensive safety approvals including:
- BS 415
- BS 7002
- SETI: IEC 950
- UL 1577 (File No: E 76222)

Applications

The CNY75 optocoupler series is designed for a wide range of isolation applications across multiple industries:

Industrial Automation

PLC input/output isolation
Motor control circuits
Industrial communication interfaces
Sensor isolation

Power Electronics

Switch-mode power supply feedback circuits
Inverter gate drive isolation
Power factor correction circuits

Medical Equipment

Patient-connected equipment isolation
Medical monitoring systems

Telecommunications

Line interface circuits
Modem isolation

General Purpose

Microprocessor system interfaces
Ground loop elimination
Noise suppression in signal transmission

Electrical Characteristics

The following table summarizes key electrical parameters (all values typical at 25°C unless otherwise specified):

Input Characteristics (IRED)

Forward voltage (I_F = 60mA): 1.25V
Reverse voltage: 5V
Peak forward current (1μs pulse width, 300Hz): 1A
Continuous forward current: 60mA
Power dissipation: 100mW

Output Characteristics (Phototransistor)

Collector-emitter voltage: 70V
Emitter-collector voltage: 7V
Collector current: 50mA
Power dissipation: 150mW
Dark current (V_CE = 10V): 100nA

Transfer Characteristics

Current Transfer Ratio (CTR):
- Group 1: 50-100% (I_F = 10mA, V_CE = 5V)
- Group 2: 80-160%
- Group 3: 130-260%
Response time (I_F = 10mA, R_L = 100Ω):
- Turn-on time (t_on): 3μs
- Turn-off time (t_off): 4μs
Isolation capacitance: 0.3pF (typical)