IS203 Optoisolator Transistor Output - Equivalent & Substitute Parts

Part Overview

The IS203 is a 6-pin optoisolator with transistor output manufactured by Isocom Components 2004 LTD. It provides galvanic isolation up to 7.5Vpk with a single channel configuration suitable for DC input applications. The device is currently in active production status with 7250 units in stock.

Finding equivalent and substitute parts becomes necessary when the IS203 reaches end-of-life status, when supply constraints occur, or when design requirements call for alternative isolation voltage ratings or output configurations. The SFH600-3 represents a viable substitute option with comparable mechanical and electrical characteristics, though with different isolation specifications and product status considerations.

Substiute Parts

IS203

Isocom Components 2004 LTDIn Stock: 7347IS203 Datasheet

Current PartRFQ

SFH600-3

Vishay Semiconductor Opto DivisionIn Stock: 1651SFH600-3 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the IS203 is determined by the following critical parameters:

• Package compatibility: 6-DIP (0.300", 7.62mm) form factor for direct PCB mounting
• Output type: Transistor output configuration for signal switching applications
• Electrical performance: Maximum output voltage of 70V and output current of 50mA per channel
• Saturation characteristics: Vce saturation at 400mV maximum
• Single channel configuration: One isolated channel per device
• Compliance standards: ROHS3 compliance and REACH unaffected status

The SFH600-3 qualifies as a substitute based on matching package type, output voltage/current ratings, saturation voltage, and compliance certifications. However, it differs in isolation voltage specification (5300Vrms versus 7.5Vpk), current transfer ratio range, switching time characteristics, and product status (Last Time Buy versus Active).

Parameter Comparison

Engineering Selection Recommendations

IS203 Selection: Maintain use of the IS203 for new designs and ongoing production. The device is in active production status with adequate inventory (7250 units in stock), ensuring supply continuity. Full ROHS3 compliance and REACH unaffected status satisfy regulatory requirements.

SFH600-3 Selection: The SFH600-3 is suitable as a substitute only when the IS203 becomes unavailable. The SFH600-3 carries Last Time Buy status, indicating limited future availability. Selection of SFH600-3 requires design validation due to differences in isolation voltage specification, current transfer ratio range, and output configuration (transistor with base versus standard transistor). The extended operating temperature range (-55°C to 100°C) of the SFH600-3 provides broader thermal coverage compared to the IS203 (-25°C to 100°C).

Both devices maintain identical maximum output voltage (70V), output current (50mA), and saturation voltage (400mV) specifications, supporting direct functional substitution in applications where isolation voltage differences are not critical design constraints.

Frequently Asked Questions (FAQ)

Q: Can the SFH600-3 directly replace the IS203 without PCB modifications?

A: Yes, both devices use identical 6-DIP (0.300", 7.62mm) through-hole packaging, enabling direct pin-for-pin substitution on existing PCBs. However, the output configuration difference (transistor with base on SFH600-3 versus standard transistor on IS203) may require circuit-level evaluation depending on application requirements.

Q: What is the primary difference between these two optoisolators?

A: The isolation voltage specification differs significantly. The IS203 provides 7.5Vpk isolation, while the SFH600-3 provides 5300Vrms isolation. The SFH600-3 also includes a base connection on the output transistor, offering additional circuit design flexibility. Current transfer ratio ranges also differ, with the IS203 providing higher minimum and maximum CTR values.

Q: Are both devices compliant with current regulatory standards?

A: Yes, both the IS203 and SFH600-3 are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements for electronic component manufacturing and use.

Q: What is the significance of the SFH600-3 Last Time Buy status?

A: Last Time Buy status indicates that Vishay Semiconductor Opto Division will discontinue production of the SFH600-3 after existing inventory is depleted. New designs should not incorporate this device. It is suitable only as a temporary substitute when the primary part becomes unavailable.

Q: Do operating temperature ranges affect substitution decisions?

A: The SFH600-3 supports a wider operating temperature range (-55°C to 100°C) compared to the IS203 (-25°C to 100°C). For applications requiring operation below -25°C, the SFH600-3 provides extended low-temperature capability. For standard industrial applications within -25°C to 100°C, both devices perform equivalently.

Q: Are there electrical performance differences that impact circuit design?

A: Yes, current transfer ratio specifications differ. The IS203 minimum CTR is 225% at 10mA, while the SFH600-3 minimum CTR is 160% at 10mA. Applications with tight CTR tolerance requirements or dependent on higher gain characteristics should account for these differences during circuit validation.