ISP521-4 Equivalent & Substitute Parts

Part Overview

The ISP521-4 is a quad-channel optoisolator with transistor output manufactured by Isocom Components 2004 LTD. This 16-DIP through-hole component provides 5300Vrms isolation voltage and is designed for applications requiring galvanic isolation with DC input and transistor output switching. The part is currently active in production with 1580 pieces in stock. Substitute parts are identified when equivalent electrical and mechanical parameters allow direct replacement in circuit designs without functional degradation.

Substiute Parts

ISP521-4

Isocom Components 2004 LTDIn Stock: 1621ISP521-4 Datasheet

Current PartRFQ

ISP521-4X

Isocom Components 2004 LTDIn Stock: 2080ISP521-4X Datasheet

Parametric EquivalentRFQ

ILQ621

Vishay Semiconductor Opto DivisionIn Stock: 1810ILQ621 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the ISP521-4 is determined by the following critical parameters:

Mandatory Matching Parameters:

• Number of Channels: 4
• Voltage - Isolation: 5300Vrms
• Output Type: Transistor
• Package / Case: 16-DIP (0.300", 7.62mm)
• Mounting Type: Through Hole
• Current Transfer Ratio range: 50% (Min) @ 5mA and 600% (Max) @ 5mA
• Vce Saturation (Max): 400mV

Allowable Parameter Variations:

• Voltage - Output (Max): May exceed 55V
• Current - Output / Channel: May equal or exceed 50mA
• Operating Temperature: May extend beyond -30°C ~ 100°C
• Current - DC Forward (If) (Max): May exceed 50mA

Parts meeting all mandatory matching parameters while maintaining or exceeding performance in allowable variation categories qualify as direct substitutes.

Parameter Comparison

Engineering Selection Recommendations

ISP521-4X (Parametric Equivalent): The ISP521-4X is a direct parametric equivalent manufactured by Isocom Components 2004 LTD. All electrical and mechanical parameters are identical to the ISP521-4. Both parts share the same series designation and active product status. This substitute provides identical performance characteristics and is suitable for direct replacement in all applications. Current inventory of 2000 pieces is available.

ILQ621 (Similar Substitute): The ILQ621 manufactured by Vishay Semiconductor Opto Division meets all mandatory substitution criteria with identical isolation voltage, channel count, current transfer ratio specifications, and package configuration. The ILQ621 provides enhanced performance in two areas: maximum output voltage of 70V (versus 55V) and extended operating temperature range of -55°C to 100°C (versus -30°C to 100°C). Both parts maintain ROHS3 compliance and identical Vce saturation specifications. The ILQ621 is suitable for applications requiring higher output voltage capability or extended low-temperature operation. Current inventory of 1800 pieces is available.

Frequently Asked Questions (FAQ)

Q: Can ISP521-4X be used as a direct replacement for ISP521-4? A: Yes. The ISP521-4X is a parametric equivalent with identical electrical and mechanical specifications. No circuit modifications are required.

Q: What are the key differences between ISP521-4 and ILQ621? A: The ILQ621 provides two performance enhancements: maximum output voltage of 70V compared to 55V, and operating temperature range extended to -55°C compared to -30°C. All other critical parameters including isolation voltage, channel count, current transfer ratio, and package configuration are identical.

Q: Is the ILQ621 suitable for low-temperature applications below -30°C? A: Yes. The ILQ621 operating temperature range extends to -55°C, making it suitable for applications requiring operation below -30°C where the ISP521-4 is not rated.

Q: Are all three parts in the same 16-DIP package? A: Yes. ISP521-4, ISP521-4X, and ILQ621 all use the 16-DIP (0.300", 7.62mm) through-hole package with identical pinout compatibility.

Q: Do all substitute parts maintain the same isolation voltage? A: Yes. ISP521-4, ISP521-4X, and ILQ621 all provide 5300Vrms isolation voltage.

Q: Are there any compliance differences between the parts? A: No. All three parts are ROHS3 compliant, REACH unaffected, and carry identical ECCN and HTSUS classifications.