TLP521G Optoisolator Equivalent & Substitute Parts

Part Overview

The TLP521G is a single-channel optoisolator with transistor output manufactured by Isocom Components 2004 LTD. This 4-DIP through-hole component provides 5300Vrms isolation and is designed for DC input applications requiring galvanic isolation in industrial and consumer electronics. The part is Active status with 4500 pieces in current inventory. Substitute parts are necessary to address supply chain flexibility, alternative packaging preferences, or series-specific design requirements while maintaining electrical and mechanical compatibility.

Key Parameters

Parameter	Value
Manufacturer Part Number	TLP521G
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
Package / Case	4-DIP (0.400", 10.16mm)
Mounting Type	Through Hole
Operating Temperature	-30°C ~ 100°C
RoHS Status	ROHS3 Compliant
Product Status	Active

Substitute Part Grouping Explanation

Substitute parts for the TLP521G are qualified based on the following critical parameters that must remain constant:

Single channel configuration (Number of Channels = 1)
Isolation voltage of 5300Vrms
Transistor output type
Current transfer ratio range: 50% minimum to 600% maximum @ 5mA
Maximum output voltage of 55V
Maximum output current of 50mA per channel
4-DIP through-hole package (0.400", 10.16mm)
Operating temperature range -30°C to 100°C
DC input type
ROHS3 compliance and REACH unaffected status

Substitutes are organized into two series groups: TLP521 series variants and ISP621 series variants. Within each series, packaging and tape/reel designations create distinct part numbers while maintaining identical electrical specifications.

Parameter Comparison

Part Number	Series	Isolation Voltage	CTR Min / Max	Output Voltage (Max)	Output Current	Turn On/Off Time (Typ)	Rise/Fall Time (Typ)	Package	Inventory
TLP521G	TLP521	5300Vrms	50% / 600%	55V	50mA	3µs, 3µs	4µs, 3µs	4-DIP	4500 Pcs
ISP521-1XG	ISP521-1	5300Vrms	50% / 600%	55V	50mA	—	4µs, 3µs	4-DIP	789 Pcs
ISP621-1XG	ISP621-1	5300Vrms	50% / 600%	55V	50mA	—	4µs, 3µs	4-DIP	1250 Pcs
ISP621-1XGR	ISP621-1	5300Vrms	50% / 600%	55V	50mA	—	4µs, 3µs	4-DIP	769 Pcs
ISP621-1XGRG	ISP621-1	5300Vrms	50% / 600%	55V	50mA	—	4µs, 3µs	4-DIP	1003 Pcs
TLP521-1XG	TLP521-1	5300Vrms	50% / 600%	55V	50mA	3µs, 3µs	4µs, 3µs	4-DIP	796 Pcs
TLP521XG	TLP521	5300Vrms	50% / 600%	55V	50mA	3µs, 3µs	4µs, 3µs	4-DIP	1085 Pcs
TLP621XBLG	TLP621	5300Vrms	50% / 600%	55V	50mA	3µs, 3µs	2µs, 3µs	4-DIP	1074 Pcs
TLP621XG	TLP621	5300Vrms	50% / 600%	55V	50mA	3µs, 3µs	2µs, 3µs	4-DIP	893 Pcs
TLP621XGBG	TLP621	5300Vrms	50% / 600%	55V	50mA	3µs, 3µs	2µs, 3µs	4-DIP	3102 Pcs
TLP621XGR	TLP621	5300Vrms	50% / 600%	55V	50mA	3µs, 3µs	2µs, 3µs	4-DIP	842 Pcs

Engineering Selection Recommendations

All substitute parts listed maintain Active product status and ROHS3 compliance with REACH unaffected designation, ensuring regulatory alignment with the TLP521G. Selection between TLP521 series and ISP621 series variants depends on design-specific timing requirements. TLP521 series parts (TLP521G, TLP521-1XG, TLP521XG) and ISP621 series parts provide specified turn-on/turn-off times of 3µs, while ISP521-1XG and ISP621 variants do not specify this parameter. TLP621 series parts (TLP621XBLG, TLP621XG, TLP621XGBG, TLP621XGR) feature faster rise time of 2µs compared to 4µs in other variants, suitable for applications requiring improved switching speed. Part number suffixes (G, XG, XGR, XGRG, XBLG, XGBG) indicate packaging and tape/reel configurations without affecting electrical performance. Inventory availability ranges from 769 to 4500 pieces across all variants.

Frequently Asked Questions (FAQ)

Q: Can ISP621 series parts directly replace TLP521G in existing designs?

A: ISP621 series parts are electrically equivalent to TLP521G across all critical parameters: isolation voltage, current transfer ratio, output voltage and current ratings, and package dimensions. The 4-DIP through-hole footprint is identical. However, ISP621 variants do not specify turn-on/turn-off timing, while TLP521G specifies 3µs. If turn-on/turn-off time is a design constraint, TLP521 series substitutes are preferred.

Q: What is the difference between TLP621 and TLP521 series substitutes?

A: Both series maintain identical isolation voltage (5300Vrms), current transfer ratio (50–600%), output ratings (55V, 50mA), and 4-DIP package. The primary difference is rise/fall time: TLP621 variants specify 2µs rise time versus 4µs in TLP521 variants. TLP621 series is suitable for applications requiring faster output switching response.

Q: Are packaging designations (G, XG, XGR, XGRG, XBLG, XGBG) interchangeable?

A: Packaging designations indicate tape/reel configuration and lead finish specifications but do not affect electrical performance or PCB footprint compatibility. All variants use the same 4-DIP (0.400", 10.16mm) through-hole package. Selection between designations depends on procurement and assembly process requirements.

Q: Do all substitute parts meet the same compliance standards as TLP521G?

A: All listed substitutes are ROHS3 compliant and REACH unaffected, matching TLP521G regulatory status. All parts are Active status with current manufacturing support.

Q: Which substitute offers the best inventory availability?

A: TLP621XGBG provides the highest inventory at 3102 pieces, followed by TLP521G at 4500 pieces. ISP521-1XG has the lowest availability at 789 pieces.

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