ISP521-1SM Optoisolator Equivalent & Substitute Parts

Part Overview

The ISP521-1SM is a single-channel optoisolator with transistor output manufactured by Isocom Components 2004 LTD. This surface mount component provides 5300Vrms isolation voltage and is designed for DC input applications requiring galvanic isolation. The part is currently active in production with ROHS3 compliance and unlimited moisture sensitivity rating. Substitute parts are identified based on matching electrical characteristics and mechanical compatibility to ensure direct functional equivalence in circuit applications.

Key Parameters

Parameter	Value
Manufacturer Part Number	ISP521-1SM
Manufacturer	Isocom Components 2004 LTD
Category	Optoisolators
Number of Channels	1
Voltage - Isolation	5300Vrms
Current Transfer Ratio (Min)	50% @ 5mA
Current Transfer Ratio (Max)	600% @ 5mA
Output Type	Transistor
Voltage - Output (Max)	55V
Current - Output / Channel	50mA
Vce Saturation (Max)	400mV
Operating Temperature	-30°C ~ 100°C
Package / Case	4-SMD (0.300", 7.62mm)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitute parts for the ISP521-1SM are qualified based on the following critical parameters that determine functional equivalence:

Isolation Voltage: 5300Vrms (all substitutes match)
Number of Channels: 1 (all substitutes match)
Output Type: Transistor (all substitutes match)
Current Transfer Ratio Range: 50% to 600% @ 5mA (all substitutes match)
Maximum Output Voltage: 55V (all substitutes match)
Maximum Output Current: 50mA per channel (all substitutes match)
Vce Saturation: 400mV maximum (all substitutes match)
Operating Temperature Range: -30°C ~ 100°C (all substitutes match)
Package / Case: 4-SMD (0.300", 7.62mm) (all substitutes match)
Input Type: DC (all substitutes match)
Mounting Type: Surface Mount (all substitutes match)
Compliance: ROHS3 Compliant, MSL 1 (Unlimited) (all substitutes match)

All identified substitute parts meet these electrical and mechanical requirements and are therefore directly interchangeable with the ISP521-1SM in circuit applications.

Parameter Comparison

Parameter	ISP521-1SM	ISP521-1XSM	TLP521-1XSM	TLP621XBLSM	TLP621XGBSM	TLP621XGRSM
Voltage - Isolation	5300Vrms	5300Vrms	5300Vrms	5300Vrms	5300Vrms	5300Vrms
Number of Channels	1	1	1	1	1	1
Current Transfer Ratio (Min)	50% @ 5mA	50% @ 5mA	50% @ 5mA	50% @ 5mA	50% @ 5mA	50% @ 5mA
Current Transfer Ratio (Max)	600% @ 5mA	600% @ 5mA	600% @ 5mA	600% @ 5mA	600% @ 5mA	600% @ 5mA
Output Type	Transistor	Transistor	Transistor	Transistor	Transistor	Transistor
Voltage - Output (Max)	55V	55V	55V	55V	55V	55V
Current - Output / Channel	50mA	50mA	50mA	50mA	50mA	50mA
Voltage - Forward (Vf) (Typ)	1.15V	1.15V	1.15V	1.15V	1.15V	1.15V
Current - DC Forward (If) (Max)	50mA	50mA	50mA	50mA	50mA	50mA
Vce Saturation (Max)	400mV	400mV	400mV	400mV	400mV	400mV
Operating Temperature	-30°C ~ 100°C	-30°C ~ 100°C	-30°C ~ 100°C	-30°C ~ 100°C	-30°C ~ 100°C	-30°C ~ 100°C
Package / Case	4-SMD (0.300", 7.62mm)	4-SMD (0.300", 7.62mm)	4-SMD (0.300", 7.62mm)	4-SMD (0.300", 7.62mm)	4-SMD (0.300", 7.62mm)	4-SMD (0.300", 7.62mm)
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

All substitute parts listed are active products with ROHS3 compliance and unlimited moisture sensitivity rating, matching the regulatory and environmental requirements of the ISP521-1SM. Selection among these equivalents may be based on inventory availability and lead time considerations. The ISP521-1XSM shares the identical ISP521-1 series designation with the main part. The TLP521-1XSM belongs to the TLP521-1 series, while TLP621XBLSM, TLP621XGBSM, and TLP621XGRSM are part of the TLP621 series. All parts maintain identical electrical performance specifications and mechanical compatibility for direct substitution in surface mount applications.

Frequently Asked Questions (FAQ)

Q: Can ISP521-1SM be directly replaced with TLP621XGRSM?

A: Yes. Both parts share identical isolation voltage (5300Vrms), current transfer ratio range (50-600% @ 5mA), output characteristics (55V maximum, 50mA per channel), and package specifications (4-SMD, 0.300" / 7.62mm). The parts are mechanically and electrically interchangeable.

Q: What is the difference between ISP521-1SM and ISP521-1XSM?

A: Both parts are from the ISP521-1 series and share all critical electrical parameters. The primary difference is the part number suffix designation. Both are functionally equivalent for circuit applications.

Q: Are TLP621 series parts compatible with ISP521-1SM?

A: Yes. TLP621XBLSM, TLP621XGBSM, and TLP621XGRSM all meet the electrical and mechanical requirements for substitution. The series designation change does not affect functional compatibility in applications requiring the specified electrical characteristics.

Q: Does package size remain consistent across all substitute parts?

A: Yes. All substitute parts use the 4-SMD (0.300", 7.62mm) package, ensuring identical PCB footprint and mounting compatibility.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts maintain ROHS3 compliance and MSL 1 (Unlimited) rating, matching the regulatory status of the ISP521-1SM.

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