ILQ66-3 Equivalent & Substitute Parts

Part Overview

The ILQ66-3 is a 4-channel optoisolator with Darlington output manufactured by Vishay Semiconductor Opto Division. It provides 5300Vrms isolation voltage and is designed for applications requiring high-voltage signal isolation in Through Hole 16-DIP packaging. The product is currently obsolete, making identification of compatible substitute components essential for ongoing system support and new design implementations.

Substiute Parts

ILQ66-3

Vishay Semiconductor Opto DivisionIn Stock: 669ILQ66-3 Datasheet

Current PartRFQ

LTV-845

Lite-On Inc.In Stock: 46343LTV-845 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the ILQ66-3 is determined by the following critical parameters:

• Package Compatibility: 16-DIP (0.300", 7.62mm) Through Hole mounting
• Channel Configuration: 4-channel Darlington output optoisolator
• Isolation Voltage: Minimum 5000Vrms (ILQ66-3 specifies 5300Vrms)
• Output Type: Darlington configuration
• Input Type: DC
• Regulatory Compliance: ROHS3 Compliant, REACH Unaffected

The LTV-845 qualifies as a substitute based on matching package geometry, channel count, output type, and isolation voltage within acceptable engineering tolerances. Both components maintain identical Through Hole 16-DIP form factors and support equivalent circuit-level integration.

Parameter Comparison

Engineering Selection Recommendations

The LTV-845 is the manufacturer-recommended substitute for the obsolete ILQ66-3. Both components maintain ROHS3 compliance and REACH unaffected status, ensuring regulatory alignment for new designs and legacy system replacements.

Selection between these components depends on application-specific requirements:

• Maximum Output Voltage: Applications requiring output voltages above 35V must retain the ILQ66-3 or identify alternative solutions, as the LTV-845 is limited to 35V maximum.
• Minimum Operating Temperature: Systems operating below -30°C require the ILQ66-3 due to its -55°C minimum specification; the LTV-845 minimum is -30°C.
• Isolation Voltage: The ILQ66-3 provides 5300Vrms isolation versus the LTV-845 at 5000Vrms. Applications with isolation voltage requirements below 5000Vrms can use the LTV-845.
• Response Time: The LTV-845 offers significantly faster rise and fall times (60µs and 53µs respectively) compared to the ILQ66-3 (200µs maximum), making it suitable for higher-speed switching applications.
• Current Transfer Ratio: The LTV-845 provides superior current transfer ratio performance (600% minimum at 1mA versus 400% at 700µA), resulting in improved switching characteristics.
• Active Production Status: The LTV-845 is in active production with substantial inventory availability (46,301 pcs), whereas the ILQ66-3 is obsolete.

Frequently Asked Questions (FAQ)

Q: Can the LTV-845 directly replace the ILQ66-3 in all applications?

A: Direct replacement is possible only when application requirements do not exceed the LTV-845 parameter limits. Verify that maximum output voltage does not exceed 35V, minimum operating temperature is not below -30°C, and isolation voltage requirement does not exceed 5000Vrms. If any of these conditions are not met, the LTV-845 is not suitable.

Q: What is the primary difference in isolation voltage between these components?

A: The ILQ66-3 provides 5300Vrms isolation while the LTV-845 provides 5000Vrms isolation. This 300Vrms difference is within typical engineering tolerances for most industrial applications. Applications with isolation voltage specifications below 5000Vrms can use the LTV-845 without concern.

Q: Are the packages physically identical?

A: Yes. Both the ILQ66-3 and LTV-845 use 16-DIP (0.300", 7.62mm) Through Hole packaging. Pin-to-pin compatibility and PCB footprint are identical, allowing direct socket substitution without layout modifications.

Q: Why does the LTV-845 have faster response times?

A: The LTV-845 specifies rise and fall times of 60µs and 53µs respectively, compared to the ILQ66-3 at 200µs maximum. This performance difference reflects different internal circuit design and manufacturing processes between Lite-On and Vishay components. The faster response time of the LTV-845 makes it suitable for higher-frequency switching applications.

Q: What is the significance of the higher Current Transfer Ratio in the LTV-845?

A: The LTV-845 minimum Current Transfer Ratio is 600% at 1mA, while the ILQ66-3 is 400% at 700µA. Higher CTR indicates more efficient signal transfer from input to output, resulting in lower input current requirements and improved switching performance. This is an advantage for the LTV-845 in most applications.

Q: Is the LTV-845 suitable for low-temperature applications?

A: The LTV-845 operating temperature range is -30°C to 100°C. Applications requiring operation below -30°C must use the ILQ66-3, which supports -55°C to 100°C. Verify your application's minimum operating temperature requirement before selecting the LTV-845.

Q: What inventory considerations should guide component selection?

A: The ILQ66-3 is obsolete with limited remaining inventory (618 pcs). The LTV-845 is in active production with substantial inventory (46,301 pcs). For new designs and long-term system support, the LTV-845 is the preferred choice due to ongoing availability and active manufacturer support.