ISP521-1BLSM Equivalent & Substitute Parts

Part Overview

The ISP521-1BLSM is a single-channel optoisolator with transistor output manufactured by Isocom Components 2004 LTD. This component provides galvanic isolation rated at 5300Vrms and is designed for DC input applications requiring isolated switching control. The part is currently active in production with 973 units in stock. Substitute parts are identified based on matching electrical characteristics, mechanical compatibility, and regulatory compliance to support component procurement flexibility and supply chain continuity.

Key Parameters

Parameter	Value
Manufacturer Part Number	ISP521-1BLSM
Manufacturer	Isocom Components 2004 LTD
Category	Optoisolators
Number of Channels	1
Voltage - Isolation	5300Vrms
Current Transfer Ratio (Min)	200% @ 1mA
Current Transfer Ratio (Max)	600% @ 1mA
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
Product Status	Active

Substitute Part Grouping Explanation

Substitute parts for the ISP521-1BLSM are qualified based on the following critical parameters that determine functional and mechanical compatibility:

Isolation Voltage: 5300Vrms (all substitutes match)
Number of Channels: 1 (all substitutes match)
Output Type: Transistor (all substitutes match)
Current Transfer Ratio Range: 200% to 600% @ 1mA (all substitutes match)
Maximum Output Voltage: 55V (all substitutes match)
Maximum Output Current: 50mA per channel (all substitutes match)
Package / Case: 4-SMD (0.300", 7.62mm) (all substitutes match)
Mounting Type: Surface Mount (all substitutes match)
Operating Temperature Range: -30°C ~ 100°C (all substitutes match)
RoHS Status: ROHS3 Compliant (all substitutes match)

All three substitute parts maintain identical electrical performance specifications and mechanical compatibility with the main part number ISP521-1BLSM.

Parameter Comparison

Parameter	ISP521-1BLSM	ISP521-1XBLSM	TLP521-1XBLSM	TLP521XBLSM
Manufacturer	Isocom Components 2004 LTD	Isocom Components 2004 LTD	Isocom Components 2004 LTD	Isocom Components 2004 LTD
Series	ISP521-1	ISP521-1	TLP521-1	TLP521
Number of Channels	1	1	1	1
Voltage - Isolation	5300Vrms	5300Vrms	5300Vrms	5300Vrms
Current Transfer Ratio (Min)	200% @ 1mA	200% @ 1mA	200% @ 1mA	200% @ 1mA
Current Transfer Ratio (Max)	600% @ 1mA	600% @ 1mA	600% @ 1mA	600% @ 1mA
Output Type	Transistor	Transistor	Transistor	Transistor
Voltage - Output (Max)	55V	55V	55V	55V
Current - Output / Channel	50mA	50mA	50mA	50mA
Voltage - Forward (Vf) (Typ)	1.15V	1.15V	1.15V	1.15V
Current - DC Forward (If) (Max)	50 mA	50 mA	50 mA	50 mA
Vce Saturation (Max)	400mV	400mV	400mV	400mV
Operating Temperature	-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)
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected
Product Status	Active	Active	Active	Active

Engineering Selection Recommendations

All substitute parts—ISP521-1XBLSM, TLP521-1XBLSM, and TLP521XBLSM—are qualified equivalents for the ISP521-1BLSM based on matching electrical and mechanical specifications. Selection among these parts may be based on:

Inventory Availability: ISP521-1XBLSM (1000 units), TLP521-1XBLSM (1138 units), TLP521XBLSM (967 units)
Regulatory Compliance: All parts maintain ROHS3 compliance and REACH unaffected status
Moisture Sensitivity: All parts rated MSL 1 (Unlimited), suitable for standard storage and handling
Product Status: All parts are active in production, ensuring long-term availability

Frequently Asked Questions (FAQ)

Q: Can ISP521-1XBLSM be used as a direct replacement for ISP521-1BLSM?

A: Yes. Both parts share identical electrical specifications including 5300Vrms isolation voltage, 200-600% current transfer ratio, 55V maximum output voltage, and 50mA output current. Both use the same 4-SMD package and surface mount configuration.

Q: What is the difference between ISP521-1XBLSM and TLP521-1XBLSM?

A: The primary difference is the series designation (ISP521-1 versus TLP521-1). Both parts maintain identical electrical performance and package specifications. Turn-on/turn-off time for TLP521-1XBLSM is specified at 3µs, 3µs, while ISP521-1BLSM does not specify this parameter.

Q: Are all substitute parts compatible with the same PCB layout?

A: Yes. All substitute parts use the identical 4-SMD (0.300", 7.62mm) package and surface mount configuration, ensuring mechanical and electrical compatibility with existing PCB designs.

Q: Do substitute parts meet the same regulatory requirements?

A: Yes. All substitute parts are ROHS3 compliant, REACH unaffected, and carry identical MSL 1 (Unlimited) ratings, meeting the same regulatory and environmental standards as the main part.

Q: Which substitute part should be selected for new designs?

A: Selection should be based on current inventory availability and supply chain considerations. All three substitute parts are functionally equivalent and suitable for new designs requiring single-channel optoisolation at 5300Vrms with transistor output.

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