ISP521-1X Equivalent & Substitute Parts

Part Overview

The ISP521-1X 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. The part is currently active in production with 45,100 units in stock. Substitute parts are identified based on matching electrical characteristics, mechanical compatibility, and compliance certifications to ensure direct functional equivalence in circuit applications.

Key Parameters

Parameter	Value
Manufacturer Part Number	ISP521-1X
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 (0.300", 7.62mm)
Operating Temperature	-30°C ~ 100°C
RoHS Status	ROHS3 Compliant
Product Status	Active

Substitute Part Grouping Explanation

Substitute parts for the ISP521-1X are qualified based on the following critical parameters that determine functional equivalence:

Isolation Voltage: 5300Vrms (exact match required)
Number of Channels: 1 (single channel configuration)
Output Type: Transistor (DC switching output)
Current Transfer Ratio Range: 50% to 600% @ 5mA (input-to-output current transfer characteristics)
Maximum Output Voltage: 55V
Maximum Output Current: 50mA per channel
Package Type: 4-DIP through-hole (0.300", 7.62mm)
Input Type: DC
Operating Temperature Range: -30°C ~ 100°C
Compliance: ROHS3 Compliant, REACH Unaffected

All identified substitutes maintain these electrical and mechanical specifications, ensuring pin-compatible and functionally equivalent operation in existing circuit designs.

Parameter Comparison

Parameter	ISP521-1X	TLP521-1X	TLP621XBL
Manufacturer	Isocom Components 2004 LTD	Isocom Components 2004 LTD	Isocom Components 2004 LTD
Number of Channels	1	1	1
Voltage - Isolation	5300Vrms	5300Vrms	5300Vrms
Current Transfer Ratio (Min)	50% @ 5mA	50% @ 5mA	50% @ 5mA
Current Transfer Ratio (Max)	600% @ 5mA	600% @ 5mA	600% @ 5mA
Output Type	Transistor	Transistor	Transistor
Voltage - Output (Max)	55V	55V	55V
Current - Output / Channel	50mA	50mA	50mA
Voltage - Forward (Vf) (Typ)	1.15V	1.15V	1.15V
Current - DC Forward (If) (Max)	50 mA	50 mA	50 mA
Vce Saturation (Max)	400mV	400mV	400mV
Rise / Fall Time (Typ)	4µs, 3µs	4µs, 3µs	2µs, 3µs
Operating Temperature	-30°C ~ 100°C	-30°C ~ 100°C	-30°C ~ 100°C
Package / Case	4-DIP (0.300", 7.62mm)	4-DIP (0.300", 7.62mm)	4-DIP (0.300", 7.62mm)
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected
Product Status	Active	Active	Active
Inventory (Pcs)	45,100	2,375	2,743

Engineering Selection Recommendations

All three parts—ISP521-1X, TLP521-1X, and TLP621XBL—are active production components from Isocom Components 2004 LTD with identical isolation voltage, channel configuration, output characteristics, and compliance certifications. They are mechanically and electrically interchangeable in 4-DIP through-hole applications.

The ISP521-1X offers the highest inventory availability at 45,100 units. The TLP521-1X and TLP621XBL are functionally equivalent alternatives with comparable stock levels. The TLP621XBL exhibits faster rise time (2µs versus 4µs), which may provide performance advantages in high-speed switching applications, though all parts meet the specified operating temperature range and compliance requirements.

Selection should be based on application-specific timing requirements, availability constraints, and supply chain considerations. All parts maintain ROHS3 compliance and REACH unaffected status, suitable for regulated industrial and consumer applications.

Frequently Asked Questions (FAQ)

Q: Can TLP521-1X be used as a direct replacement for ISP521-1X?

A: Yes. Both parts share identical electrical specifications including 5300Vrms isolation voltage, 1-channel configuration, 50% to 600% current transfer ratio, 55V maximum output voltage, and 50mA output current. They use the same 4-DIP package and operate across the same temperature range. Pin-for-pin substitution is supported.

Q: What is the difference between TLP621XBL and ISP521-1X?

A: The TLP621XBL is electrically equivalent to the ISP521-1X across all critical parameters. The primary difference is rise time: TLP621XBL has 2µs rise time compared to 4µs for ISP521-1X. This faster switching characteristic may be beneficial in applications requiring rapid signal transitions. All other electrical and mechanical specifications are identical.

Q: Are all three parts pin-compatible?

A: Yes. ISP521-1X, TLP521-1X, and TLP621XBL all use the 4-DIP (0.300", 7.62mm) through-hole package with identical pinout. They are directly interchangeable without PCB modifications.

Q: Do these parts meet environmental compliance requirements?

A: All three parts are ROHS3 compliant and REACH unaffected, meeting current environmental regulations for industrial and consumer electronics applications.

Q: Which part should I select based on availability?

A: ISP521-1X has the highest inventory at 45,100 units. TLP621XBL and TLP521-1X have comparable availability at 2,743 and 2,375 units respectively. Selection should consider project lead times and supply chain requirements.

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

A: All three parts operate across -30°C to 100°C. Applications requiring operation beyond this range require alternative component selection.

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