TIL925 Quad-Channel Optocoupler Technical Summary

Overview

The TIL925 is a high-performance quad-channel optocoupler designed to provide electrical isolation between input and output circuits. Each channel consists of a gallium-arsenide (GaAs) light-emitting diode (LED) optically coupled to a silicon n-p-n Darlington phototransistor. This device is part of a family that includes single-channel (TIL923), dual-channel (TIL924), and quad-channel (TIL925) variants, packaged in 4-pin, 8-pin, and 16-pin configurations respectively.

The TIL925 is particularly notable for its high current-transfer ratio (CTR) of 500% minimum in standard versions, with selected versions available for even higher performance requirements. This makes it suitable for applications requiring robust signal isolation with minimal signal degradation.

Key Features

• Quad-Channel Isolation: Four independent isolation channels in a single 16-pin package
• High Current-Transfer Ratio: Minimum 500% CTR ensures reliable signal transmission
• Darlington Phototransistor Output: Provides high current gain for improved sensitivity
• GaAs LED Input: Offers high efficiency and fast response times
• Electrical Isolation: Typical isolation voltage of 2500V_rms between input and output
• Wide Operating Temperature Range: Suitable for industrial environments (-40°C to +85°C)
• Compact Package: 16-pin DIP (Dual In-line Package) saves board space
• Reliable Performance: Tested and guaranteed parameters for consistent operation

Applications

The TIL925 is designed for use in a wide range of applications requiring electrical isolation and signal transmission:

• Industrial Control Systems: PLCs, motor controls, and factory automation
• Power Supply Regulation: Feedback circuits in switched-mode power supplies
• Medical Equipment: Patient-isolated monitoring systems
• Telecommunications: Signal isolation in communication interfaces
• Computer Peripherals: Isolation in serial communications and interface circuits
• Test and Measurement Equipment: Isolated signal acquisition systems
• Automotive Electronics: Noise-sensitive control circuits

Electrical Characteristics

Absolute Maximum Ratings

• LED Forward Current: 60 mA (continuous)
• LED Reverse Voltage: 3 V
• Collector-Emitter Voltage: 30 V
• Emitter-Collector Voltage: 7 V
• Collector Current: 150 mA
• Total Power Dissipation: 250 mW per channel
• Isolation Voltage: 2500 V_rms (1 minute)
• Operating Temperature Range: -40°C to +85°C
• Storage Temperature Range: -55°C to +125°C

Recommended Operating Conditions

• LED Forward Current: 10 mA to 50 mA
• Collector-Emitter Voltage: 15 V maximum
• Ambient Temperature: -40°C to +85°C

Optical Characteristics

• Current Transfer Ratio (CTR): 500% minimum (standard version)
• LED Forward Voltage: 1.15 V typical at 10 mA
• Response Time (Turn-on): 15 µs typical
• Response Time (Turn-off): 100 µs typical
• Isolation Resistance: 10¹¹ Ω minimum
• Capacitance (Input-Output): 1 pF typical

Package Information

16-Pin Dual In-Line Package (DIP)

• Package Type: Plastic DIP-16
• Dimensions: 19.3 mm x 6.35 mm x 4.57 mm (LxWxH)
• Pin Spacing: 2.54 mm (0.1 inch) between pins
• Row Spacing: 7.62 mm (0.3 inch) between rows
• Lead Material: Copper alloy
• Lead Finish: Tin-plated
• Weight: Approximately 1.2 grams

Pin Configuration

• Pins 1, 4, 8, 11: Anodes of input LEDs (Channels 1-4 respectively)
• Pins 2, 5, 7, 10: Cathodes of input LEDs (Channels 1-4 respectively)
Pins 3, 6, 9, 12: No connection (reserved)
• Pins 13, 14, 15, 16: Emitters of output phototransistors (Channels 1-4 respectively)
• Pins 17, 18, 19, 20: Collectors of output phototransistors (Channels 1-4 respectively)

Reliability and Safety

The TIL925 optocoupler meets stringent reliability and safety standards:

• Isolation Voltage: Tested at 2500V_rms for 1 minute
• UL Recognition: File E69938
• CSA Certification: Component Acceptance Notice #5
• VDE Approval: DIN EN 60747-5-2 (VDE 0884 Part 2)
• Flammability Rating: UL94 V-0
• Moisture Sensitivity Level (MSL): MSL 1 (Unlimited floor life at ≤30°C/85% RH)

Design Considerations

Input Circuit Design

When designing the input circuit:

• Use a current-limiting resistor in series with the LED to maintain forward current within specified limits
• Consider the forward voltage drop (typically 1.15V at 10mA) when calculating the resistor value
• For pulse operation, ensure the peak current does not exceed the absolute maximum rating

Output Circuit Design

For optimal output performance:

• Include a pull-up resistor at the collector to establish proper output voltage levels
• Consider the Darlington configuration's higher saturation voltage when designing logic interfaces
• For fast switching applications, minimize stray capacitance in the output circuit

Ordering Information

The TIL925 is available in several versions:

• TIL925: