TLP621G Optoisolator Equivalent & Substitute Parts

Part Overview

The TLP621G 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 full RoHS3 compliance and unlimited moisture sensitivity rating. Substitute parts are identified based on matching electrical specifications, isolation voltage, output characteristics, and package compatibility to ensure direct functional replacement in circuit designs.

Key Parameters

Parameter	Value
Manufacturer Part Number	TLP621G
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-DIP (0.400", 10.16mm)
Mounting Type	Through Hole
RoHS Status	ROHS3 Compliant
Product Status	Active

Substitute Part Grouping Explanation

Substitute parts for the TLP621G are qualified based on the following critical parameters that determine functional equivalence:

Mandatory Matching Parameters:

Voltage - Isolation: 5300Vrms
Number of Channels: 1
Output Type: Transistor
Voltage - Output (Max): 55V
Current - Output / Channel: 50mA
Vce Saturation (Max): 400mV
Current Transfer Ratio (Min): 50% @ 5mA
Current Transfer Ratio (Max): 600% @ 5mA
Package / Case: 4-DIP (0.400", 10.16mm)
Mounting Type: Through Hole
Operating Temperature: -30°C ~ 100°C
Input Type: DC

Acceptable Variation Parameters:

Turn On / Turn Off Time: Variations permitted (3µs typical for TLP621 series; not specified for ISP621-1 series)
Rise / Fall Time: Variations permitted (2µs/3µs for TLP621 series; 4µs/3µs for ISP521-1 and ISP621-1 series)

All substitute parts maintain Active product status, ROHS3 compliance, and unlimited moisture sensitivity rating (MSL 1).

Parameter Comparison

Parameter	TLP621G	ISP521-1XG	ISP621-1XG	ISP621-1XGR	ISP621-1XGRG	TLP521-1XG	TLP521XG	TLP621XBLG	TLP621XG	TLP621XGBG	TLP621XGR
Number of Channels	1	1	1	1	1	1	1	1	1	1	1
Voltage - Isolation	5300Vrms	5300Vrms	5300Vrms	5300Vrms	5300Vrms	5300Vrms	5300Vrms	5300Vrms	5300Vrms	5300Vrms	5300Vrms
Current Transfer Ratio (Min)	50% @ 5mA	50% @ 5mA	50% @ 5mA	50% @ 5mA	50% @ 5mA	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	600% @ 5mA	600% @ 5mA	600% @ 5mA	600% @ 5mA	600% @ 5mA
Output Type	Transistor	Transistor	Transistor	Transistor	Transistor	Transistor	Transistor	Transistor	Transistor	Transistor	Transistor
Voltage - Output (Max)	55V	55V	55V	55V	55V	55V	55V	55V	55V	55V	55V
Current - Output / Channel	50mA	50mA	50mA	50mA	50mA	50mA	50mA	50mA	50mA	50mA	50mA
Voltage - Forward (Vf) (Typ)	1.15V	1.15V	1.15V	1.15V	1.15V	1.15V	1.15V	1.15V	1.15V	1.15V	1.15V
Current - DC Forward (If) (Max)	50 mA	50 mA	50 mA	50 mA	50 mA	50 mA	50 mA	50 mA	50 mA	50 mA	50 mA
Vce Saturation (Max)	400mV	400mV	400mV	400mV	400mV	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	-30°C ~ 100°C	-30°C ~ 100°C	-30°C ~ 100°C	-30°C ~ 100°C	-30°C ~ 100°C
Package / Case	4-DIP (0.400", 10.16mm)	4-DIP (0.400", 10.16mm)	4-DIP (0.400", 10.16mm)	4-DIP (0.400", 10.16mm)	4-DIP (0.400", 10.16mm)	4-DIP (0.400", 10.16mm)	4-DIP (0.400", 10.16mm)	4-DIP (0.400", 10.16mm)	4-DIP (0.400", 10.16mm)	4-DIP (0.400", 10.16mm)	4-DIP (0.400", 10.16mm)
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Active	Active	Active	Active	Active	Active	Active	Active	Active	Active	Active

Engineering Selection Recommendations

All listed substitute parts maintain full electrical and mechanical compatibility with the TLP621G. Selection among equivalent parts should be based on:

Availability and Lead Time: Inventory levels vary across substitute part numbers. TLP621XGBG offers the highest stock (3102 pcs), while ISP621-1XGR offers the lowest (769 pcs).

Series Designation: TLP621 series parts (TLP621G, TLP621XBLG, TLP621XG, TLP621XGBG, TLP621XGR) and TLP521 series parts (TLP521-1XG, TLP521XG) share identical electrical specifications with the main part. ISP621-1 series (ISP621-1XG, ISP621-1XGR, ISP621-1XGRG) and ISP521-1 series (ISP521-1XG) are functionally equivalent with minor timing variations in rise/fall time specifications.

Compliance and Certification: All parts carry ROHS3 compliance, REACH Unaffected status, and EAR99 ECCN classification. Moisture sensitivity level is uniform across all parts (MSL 1 - Unlimited).

Timing Characteristics: TLP621 and TLP521 series maintain turn-on/turn-off times of 3µs typical with rise/fall times of 2µs/3µs or 4µs/3µs. ISP621-1 and ISP521-1 series do not specify turn-on/turn-off times but maintain rise/fall times of 4µs/3µs. Applications with strict timing requirements should prioritize TLP621 or TLP521 series variants.

Frequently Asked Questions (FAQ)

Q: Can I substitute TLP621G with ISP621-1XG in my circuit?

A: Yes. Both parts share identical isolation voltage (5300Vrms), current transfer ratio range (50%-600% @ 5mA), output voltage (55V max), output current (50mA), and saturation voltage (400mV max). The 4-DIP through-hole package is identical. The primary difference is rise/fall time specification: TLP621G specifies 2µs/3µs while ISP621-1XG specifies 4µs/3µs. If your circuit timing margin accommodates the slower rise/fall time, substitution is valid.

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

A: Both series are functionally equivalent for the parameters provided. TLP521-1XG and TLP521XG are direct substitutes for TLP621G with identical electrical specifications and timing characteristics. Series designation reflects internal design variants from Isocom Components 2004 LTD but does not affect circuit-level compatibility.

Q: Are ISP621-1 parts equivalent to TLP621G?

A: Yes. ISP621-1XG, ISP621-1XGR, and ISP621-1XGRG maintain all critical electrical parameters matching TLP621G. The ISP designation indicates an alternative product line from the same manufacturer. Rise/fall time specification differs (4µs/3µs vs. 2µs/3µs), but all other parameters are identical. Substitution is valid for applications where the timing difference does not impact circuit performance.

Q: Can I use these parts interchangeably on the same PCB?

A: Yes. All substitute parts use the 4-DIP (0.400", 10.16mm) through-hole package with identical pin configuration. PCB footprints and assembly processes require no modification. Parts can be used interchangeably based on availability and lead time.

Q: What compliance certifications apply to all substitute parts?

A: All parts are ROHS3 compliant, REACH Unaffected, and classified as EAR99 for export control purposes. Moisture sensitivity level is MSL 1 (Unlimited) across all parts, indicating no special moisture handling requirements during storage or assembly.

Q: Which substitute part has the best availability?

A: TLP621XGBG offers the highest inventory level at 3102 pcs in stock. For applications requiring immediate procurement, this part number provides the shortest lead time among all equivalents.

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