CNW85 Equivalent & Substitute Parts

Part Overview

The CNW85 is an optoisolator transistor with base output manufactured by onsemi, designed for galvanic isolation applications requiring high voltage isolation. This 6-DIP through-hole component provides 5900Vrms isolation with a single channel transistor output configuration. The CNW85 is classified as obsolete, making identification of suitable substitute components essential for ongoing system support and new design implementations. The obsolete status necessitates evaluation of active alternative optoisolators that maintain functional compatibility within the specified electrical and mechanical parameters.

Substiute Parts

CNW85

onsemiIn Stock: 1581CNW85 Datasheet

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CNY171M

onsemiIn Stock: 20430CNY171M Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the CNW85 is evaluated based on the following critical parameters that define functional compatibility:

Isolation Voltage: The CNW85 provides 5900Vrms isolation. Substitute components must maintain isolation voltage at or above this specification to ensure equivalent galvanic separation in high-voltage applications.

Output Configuration: The transistor with base output type is mandatory for circuits designed around base-driven switching topologies. Substitute parts must preserve this output architecture.

Single Channel Architecture: The CNW85 is a single-channel device. Substitute components must be single-channel to match the original pinout and functional requirements.

Current Transfer Ratio Range: The CTR range of 0.63% to 3.20% @ 10mA defines the gain characteristics. Substitute parts must operate within compatible CTR specifications to maintain circuit performance.

Output Voltage and Current Ratings: Maximum output voltage of 80V and output current of 100mA per channel establish the load-driving capability. Substitute components must support these electrical limits.

Package and Mounting: The 6-DIP through-hole package with 0.400" (10.16mm) pitch is a physical requirement for PCB compatibility. Substitute parts must use identical or compatible package specifications.

The CNY171M is identified as a substitute based on matching the core functional parameters: single-channel transistor with base output, through-hole 6-DIP package, and compatible isolation voltage, output voltage, and current ratings.

Parameter Comparison

Engineering Selection Recommendations

Product Status Consideration: The CNW85 is obsolete, while the CNY171M is active and in production. For new designs or system replacements requiring long-term component availability, the CNY171M provides assured supply continuity.

Compliance and Certification: The CNY171M is ROHS3 compliant, meeting current environmental and regulatory standards. The CNW85 is RoHS non-compliant. Systems requiring compliance with modern procurement standards should transition to the CNY171M.

Electrical Parameter Differences: The CNY171M exhibits significantly higher current transfer ratio (40-80% versus 0.63-3.20%), lower maximum output voltage (70V versus 80V), and lower maximum output current (50mA versus 100mA). These differences require circuit-level evaluation to confirm functional equivalence in the target application.

Isolation Voltage: The CNY171M provides 4170Vrms isolation compared to the CNW85's 5900Vrms. Applications requiring the full 5900Vrms isolation specification cannot use the CNY171M as a direct substitute.

Package Considerations: Both components use 6-DIP through-hole packages, but with different pitch specifications (0.300" versus 0.400"). PCB layout modifications may be required for physical compatibility.

Frequently Asked Questions (FAQ)

Q: Can the CNY171M directly replace the CNW85 in existing PCB designs?

A: Physical replacement requires PCB layout modification due to different DIP pitch specifications (0.300" for CNY171M versus 0.400" for CNW85). Electrical compatibility depends on application-specific requirements for isolation voltage, output current, and current transfer ratio characteristics.

Q: What is the primary difference in current transfer ratio between these components?

A: The CNW85 has a CTR range of 0.63-3.20% @ 10mA, while the CNY171M has a CTR range of 40-80% @ 10mA. The CNY171M provides approximately 12-100 times higher gain. Circuit designs relying on the low CTR characteristics of the CNW85 require redesign to accommodate the CNY171M's higher gain.

Q: Is the CNY171M suitable for applications requiring 5900Vrms isolation?

A: No. The CNY171M provides 4170Vrms isolation, which is 1730Vrms lower than the CNW85 specification. Applications with isolation voltage requirements exceeding 4170Vrms cannot use the CNY171M.

Q: What are the output current limitations when using the CNY171M?

A: The CNY171M maximum output current is 50mA per channel, compared to 100mA for the CNW85. Applications requiring output currents above 50mA cannot use the CNY171M without additional output buffering or alternative component selection.

Q: Does the CNY171M meet modern regulatory compliance requirements?

A: Yes. The CNY171M is ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory standards. The CNW85 is RoHS non-compliant and may not be acceptable for new system designs subject to modern procurement requirements.

Q: Are there timing differences between the CNW85 and CNY171M?

A: The CNY171M specifies turn-on/turn-off times of 2µs and 3µs, and rise/fall times of 4µs and 4.6µs (max). The CNW85 does not provide timing specifications. Applications with timing-critical requirements should evaluate the CNY171M's switching characteristics against circuit timing margins.