ISP521-1G Optoisolator Equivalent & Substitute Parts

Part Overview

The ISP521-1G is a single-channel optoisolator with transistor output manufactured by Isocom Components 2004 LTD. This 4-DIP through-hole component provides 5300Vrms isolation voltage and is designed for DC input applications requiring galvanic isolation in industrial and consumer electronics. The part is currently active in production with 1171 units in stock. Substitute parts are necessary to address supply chain variability, inventory optimization, and application-specific performance requirements while maintaining electrical and mechanical compatibility.

Key Parameters

Parameter	Value
Isolation Voltage	5300Vrms
Number of Channels	1
Output Type	Transistor
Current Transfer Ratio (Min)	50% @ 5mA
Current Transfer Ratio (Max)	600% @ 5mA
Maximum Output Voltage	55V
Maximum Output Current	50mA
Vce Saturation (Max)	400mV
Operating Temperature Range	-30°C to 100°C
Package Type	4-DIP (0.400", 10.16mm)
Mounting Type	Through Hole
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the ISP521-1G is determined by strict equivalence across the following critical parameters:

Isolation voltage: 5300Vrms (mandatory match)
Number of channels: 1 (mandatory match)
Output type: Transistor (mandatory match)
Current transfer ratio range: 50% to 600% @ 5mA (mandatory match)
Maximum output voltage: 55V (mandatory match)
Maximum output current: 50mA (mandatory match)
Vce saturation: 400mV maximum (mandatory match)
Operating temperature: -30°C to 100°C (mandatory match)
Package: 4-DIP through-hole (mandatory match)
RoHS compliance: ROHS3 Compliant (mandatory match)

All substitute parts listed maintain these electrical and mechanical specifications. Variations in rise/fall time and turn-on/turn-off time do not affect substitution eligibility as these parameters remain within acceptable operational ranges for the ISP521-1 series and compatible TLP521/TLP621 series variants.

Parameter Comparison

Part Number	Manufacturer	Series	Isolation Voltage	Channels	Output Type	CTR Min @ 5mA	CTR Max @ 5mA	Vout Max	Iout Max	Vce Sat Max	Temp Range	Package	Inventory
ISP521-1G	Isocom	ISP521-1	5300Vrms	1	Transistor	50%	600%	55V	50mA	400mV	-30 to 100°C	4-DIP	1171
ISP521-1XG	Isocom	ISP521-1	5300Vrms	1	Transistor	50%	600%	55V	50mA	400mV	-30 to 100°C	4-DIP	789
ISP621-1XG	Isocom	ISP621-1	5300Vrms	1	Transistor	50%	600%	55V	50mA	400mV	-30 to 100°C	4-DIP	1250
ISP621-1XGR	Isocom	ISP621-1	5300Vrms	1	Transistor	50%	600%	55V	50mA	400mV	-30 to 100°C	4-DIP	769
ISP621-1XGRG	Isocom	ISP621-1	5300Vrms	1	Transistor	50%	600%	55V	50mA	400mV	-30 to 100°C	4-DIP	1003
TLP521-1XG	Isocom	TLP521-1	5300Vrms	1	Transistor	50%	600%	55V	50mA	400mV	-30 to 100°C	4-DIP	796
TLP521XG	Isocom	TLP521	5300Vrms	1	Transistor	50%	600%	55V	50mA	400mV	-30 to 100°C	4-DIP	1085
TLP621XBLG	Isocom	TLP621	5300Vrms	1	Transistor	50%	600%	55V	50mA	400mV	-30 to 100°C	4-DIP	1074
TLP621XG	Isocom	TLP621	5300Vrms	1	Transistor	50%	600%	55V	50mA	400mV	-30 to 100°C	4-DIP	893
TLP621XGBG	Isocom	TLP621	5300Vrms	1	Transistor	50%	600%	55V	50mA	400mV	-30 to 100°C	4-DIP	3102
TLP621XGR	Isocom	TLP621	5300Vrms	1	Transistor	50%	600%	55V	50mA	400mV	-30 to 100°C	4-DIP	842

Engineering Selection Recommendations

All listed substitute parts are manufactured by Isocom Components 2004 LTD and maintain active product status. Each part is ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements. Selection among equivalent parts should be based on inventory availability and application-specific timing requirements, as all parts satisfy the electrical and mechanical specifications of the ISP521-1G.

For applications where inventory is critical, TLP621XGBG offers the highest stock level at 3102 units. ISP621-1XG provides the next highest availability at 1250 units. All parts are suitable for through-hole PCB assembly and operate across the full -30°C to 100°C temperature range.

Frequently Asked Questions (FAQ)

Q: Can TLP621 series parts directly replace ISP521-1G?

A: Yes. TLP621XBLG, TLP621XG, TLP621XGBG, and TLP621XGR are direct electrical and mechanical equivalents. All maintain 5300Vrms isolation, 50% to 600% current transfer ratio, 55V maximum output voltage, and 4-DIP through-hole packaging. The TLP621 series designation indicates a different product line within Isocom's portfolio, but electrical parameters are identical to ISP521-1G specifications.

Q: What is the difference between ISP521-1XG and ISP521-1G?

A: Both parts belong to the ISP521-1 series and share identical electrical specifications. The suffix variation (G vs. XG) reflects packaging or tape/reel configuration differences, not functional performance. Both are suitable substitutes.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts carry ROHS3 compliance certification and are REACH unaffected, meeting current environmental regulations for electronic component manufacturing and distribution.

Q: Can I use TLP521-1XG instead of ISP521-1G in existing designs?

A: Yes. TLP521-1XG maintains identical electrical specifications including 5300Vrms isolation voltage, 50% to 600% current transfer ratio, 55V maximum output voltage, 50mA maximum output current, and 4-DIP through-hole package. The part is mechanically and electrically interchangeable.

Q: Which substitute part has the best inventory availability?

A: TLP621XGBG offers the highest stock level at 3102 units. This part is fully equivalent to ISP521-1G across all critical parameters.

Q: Do all substitute parts operate across the same temperature range?

A: Yes. All substitute parts operate from -30°C to 100°C, matching the ISP521-1G operating temperature specification.

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