TLP521-1SM Optoisolator Equivalent & Substitute Parts

Part Overview

The TLP521-1SM is an active optoisolator from Isocom Components 2004 LTD, featuring transistor output with 5300Vrms isolation voltage and single-channel configuration in 4-SMD surface mount packaging. This component is designed for DC input applications requiring galvanic isolation with 50mA output current capability. The part is in active product status with full RoHS3 compliance and unlimited moisture sensitivity rating. Substitute parts are identified based on matching electrical isolation characteristics, output specifications, and mechanical compatibility within the same package footprint.

Key Parameters

Parameter	Value
Manufacturer Part Number	TLP521-1SM
Manufacturer	Isocom Components 2004 LTD
Category	Optoisolators
Series	TLP521-1
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)
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)
Product Status	Active

Substitute Part Grouping Explanation

Substitute parts for the TLP521-1SM are qualified based on the following critical parameters that determine functional interchangeability:

Isolation Voltage: All substitutes maintain 5300Vrms isolation voltage, ensuring equivalent galvanic separation capability.

Output Configuration: All substitutes feature single-channel transistor output with 50mA maximum output current and 55V maximum output voltage, matching the primary part's drive capability.

Current Transfer Ratio: All substitutes maintain the 50% minimum and 600% maximum CTR range at 5mA input, ensuring consistent optical coupling efficiency.

Saturation Voltage: All substitutes specify 400mV maximum Vce saturation, maintaining equivalent output impedance characteristics.

Package Footprint: All substitutes use 4-SMD (0.300", 7.62mm) surface mount packaging, enabling direct PCB layout compatibility.

Operating Temperature Range: All substitutes operate across -30°C to 100°C, matching thermal performance requirements.

Compliance Status: All substitutes maintain ROHS3 compliance and MSL Level 1 rating, ensuring equivalent environmental and handling requirements.

The TLP521-1 series (TLP521-1SM, TLP521-1XSM) and TLP621 series (TLP621XBLSM, TLP621XGBSM, TLP621XGRSM) variants differ primarily in timing characteristics, with TLP621 variants offering faster rise/fall times (2µs vs 4µs rise time). The ISP521-1XSM variant from the ISP521-1 series provides equivalent performance with undocumented turn-on/turn-off timing specifications.

Parameter Comparison

Parameter	TLP521-1SM	TLP521-1XSM	ISP521-1XSM	TLP621XBLSM	TLP621XGBSM	TLP621XGRSM
Series	TLP521-1	TLP521-1	ISP521-1	TLP621	TLP621	TLP621
Number of Channels	1	1	1	1	1	1
Voltage - Isolation	5300Vrms	5300Vrms	5300Vrms	5300Vrms	5300Vrms	5300Vrms
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
Turn On / Turn Off Time (Typ)	3µs, 3µs	3µs, 3µs	—	3µs, 3µs	3µs, 3µs	3µs, 3µs
Rise / Fall Time (Typ)	4µs, 3µs	4µs, 3µs	4µs, 3µs	2µs, 3µs	2µs, 3µs	2µs, 3µs
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)
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)
Product Status	Active	Active	Active	Active	Active	Active

Engineering Selection Recommendations

All listed substitute parts maintain active product status with full ROHS3 compliance and MSL Level 1 rating, ensuring equivalent regulatory and environmental qualification. Selection between TLP521-1 series and TLP621 series variants depends on timing performance requirements. TLP521-1SM and TLP521-1XSM provide 4µs rise time, while TLP621XBLSM, TLP621XGBSM, and TLP621XGRSM offer improved 2µs rise time performance. The ISP521-1XSM variant from the ISP521 series provides equivalent isolation and output specifications with undocumented turn-on/turn-off timing. All parts share identical maximum output voltage (55V), output current (50mA), and saturation voltage (400mV) characteristics, ensuring equivalent circuit performance in standard isolation applications. Inventory availability ranges from 762 to 3040 pieces across substitute variants, with TLP621XGRSM offering the highest stock level at 3040 pieces.

Frequently Asked Questions (FAQ)

Q: Can TLP621 series parts directly replace TLP521-1SM in existing designs?

A: Yes. TLP621XBLSM, TLP621XGBSM, and TLP621XGRSM are direct pin-compatible substitutes with identical isolation voltage (5300Vrms), output current (50mA), and package footprint (4-SMD). The primary difference is faster rise time (2µs vs 4µs), which improves switching performance without affecting circuit compatibility.

Q: What is the difference between TLP521-1SM and TLP521-1XSM?

A: Both parts belong to the TLP521-1 series with identical electrical specifications including 5300Vrms isolation, 50% to 600% CTR range, 3µs turn-on/turn-off time, and 4µs rise time. The suffix variation indicates packaging or supplier designation but does not affect functional performance.

Q: Is ISP521-1XSM a suitable replacement for TLP521-1SM?

A: ISP521-1XSM provides equivalent isolation voltage (5300Vrms), output current (50mA), and package configuration (4-SMD). However, turn-on/turn-off timing specifications are not documented for this variant. Substitution is appropriate for applications where timing specifications are not critical.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts (TLP521-1XSM, ISP521-1XSM, TLP621XBLSM, TLP621XGBSM, TLP621XGRSM) maintain ROHS3 compliance and MSL Level 1 rating, matching the primary part's environmental qualification.

Q: What is the significance of the 2µs vs 4µs rise time difference?

A: TLP621 series variants offer 2µs rise time compared to 4µs for TLP521-1 series. This faster switching characteristic improves signal fidelity in high-frequency isolation applications. Selection depends on circuit timing requirements; both are functionally compatible in standard applications.

Q: Can these parts be used interchangeably in high-temperature applications?

A: Yes. All substitute parts operate across the identical temperature range (-30°C to 100°C), ensuring equivalent thermal performance in specified operating conditions.

Q: What packaging considerations apply to these optoisolators?

A: All parts use 4-SMD (0.300", 7.62mm) surface mount packaging, enabling direct PCB layout compatibility without redesign. MSL Level 1 rating indicates unlimited shelf life under standard storage conditions.

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