PS9121-F3-AX Equivalent & Substitute Parts

Part Overview

The PS9121-F3-AX is a logic output optoisolator manufactured by CEL, designed for high-speed isolation applications requiring 3750Vrms isolation voltage and 15kV/µs common mode transient immunity. This component features open collector output configuration with 15Mbps data rate capability and is housed in a 5-SO surface mount package.

The PS9121-F3-AX has been discontinued at DiGi Electronics, necessitating identification of functionally equivalent substitute components. Alternative parts must maintain compatibility with the isolation voltage, output type, package configuration, and operating temperature range to ensure direct replacement capability in existing designs.

Substiute Parts

PS9121-F3-AX

CELIn Stock: 6812PS9121-F3-AX Datasheet

Current PartRFQ

HCPL-M611-560E

Broadcom LimitedIn Stock: 4062HCPL-M611-560E Datasheet

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PS9122-F3-AX

Renesas Electronics CorporationIn Stock: 18447PS9122-F3-AX Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the PS9121-F3-AX is determined by strict adherence to the following critical parameters:

Mandatory Compatibility Criteria:

• Isolation voltage: 3750Vrms (exact match required)
• Number of channels: 1 (single channel configuration)
• Output type: Open Collector (topology requirement)
• Package / Case: 6-SOIC (0.173", 4.40mm Width), 5 Leads (physical and electrical footprint)
• Mounting type: Surface Mount (assembly compatibility)
• Input type: DC (signal interface)

Performance Parameters Allowing Variation:

• Common Mode Transient Immunity: 10kV/µs or higher acceptable
• Data Rate: 1Mbps or higher acceptable
• Current - Output / Channel: 20mA or higher acceptable
• Operating Temperature: -40°C to 85°C minimum range acceptable
• Propagation Delay: Variation acceptable if system timing permits

The substitute parts HCPL-M611-560E and PS9122-F3-AX meet all mandatory criteria while offering alternative performance characteristics suitable for different application requirements.

Parameter Comparison

Engineering Selection Recommendations

HCPL-M611-560E (Broadcom Limited): This substitute is suitable for applications where higher output current capacity (50mA versus 25mA) is beneficial. The Schottky clamped output configuration provides faster switching characteristics. The 10kV/µs CMTI rating remains adequate for most isolation applications, though it is lower than the original PS9121-F3-AX specification. Supply voltage requirement of 4.5V to 5.5V differs from the original 2.7V to 3.6V range and must be verified against system power architecture. Product status is Active, ensuring long-term availability and supply chain stability. ROHS3 compliance and MSL 1 rating match the original component.

PS9122-F3-AX (Renesas Electronics Corporation): This substitute maintains identical isolation voltage (3750Vrms) and CMTI rating (15kV/µs) as the original PS9121-F3-AX, providing direct performance equivalence in these critical parameters. However, the data rate is significantly reduced to 1Mbps compared to 15Mbps, and propagation delay is substantially higher (700ns/500ns versus 75ns/75ns). This substitute is appropriate only for low-speed isolation applications where timing margins are not constrained. Supply voltage requirement is 7V, differing from the original specification. Product status is Active with extended operating temperature range (-40°C to 100°C). ROHS3 compliance and MSL 1 rating match the original component.

Selection Basis: Both substitute parts maintain the mandatory compatibility criteria: 3750Vrms isolation, single channel, open collector output, identical package configuration, and surface mount assembly. Selection between substitutes depends on application-specific requirements for data rate, output current, supply voltage, and CMTI performance. HCPL-M611-560E is recommended for higher-speed applications with 4.5V to 5.5V supply availability. PS9122-F3-AX is recommended for low-speed applications with 7V supply availability and extended temperature operation.

Frequently Asked Questions (FAQ)

Q: Can HCPL-M611-560E directly replace PS9121-F3-AX in all applications?

A: HCPL-M611-560E is physically and electrically compatible in terms of package, isolation voltage, and output type. However, the supply voltage range differs (4.5V–5.5V versus 2.7V–3.6V), and CMTI is reduced to 10kV/µs. Applications operating at 2.7V–3.6V supply or requiring 15kV/µs CMTI must verify compatibility before substitution.

Q: What is the primary limitation of PS9122-F3-AX as a substitute?

A: PS9122-F3-AX has significantly reduced data rate (1Mbps versus 15Mbps) and substantially higher propagation delay (700ns/500ns versus 75ns/75ns). This substitute is suitable only for low-speed isolation applications where timing constraints are not critical. High-speed applications require HCPL-M611-560E or continued sourcing of PS9121-F3-AX inventory.

Q: Are all three parts pin-compatible?

A: Yes. PS9121-F3-AX, HCPL-M611-560E, and PS9122-F3-AX share identical package configuration (6-SOIC, 0.173" width, 5 leads) and pinout, enabling direct PCB footprint compatibility.

Q: What compliance certifications apply to substitute parts?

A: Both HCPL-M611-560E and PS9122-F3-AX are ROHS3 compliant, REACH unaffected, and classified as EAR99 for export control purposes. Moisture sensitivity level is MSL 1 (unlimited) for both substitutes, matching the original PS9121-F3-AX specification.

Q: Which substitute offers the best performance match to PS9121-F3-AX?

A: PS9122-F3-AX matches the original CMTI specification (15kV/µs) and isolation voltage exactly. However, HCPL-M611-560E offers superior data rate performance (10MBd versus 1Mbps) and higher output current capacity (50mA versus 25mA). Selection depends on whether CMTI performance or data rate performance is the primary design constraint.

Q: Can supply voltage differences affect circuit operation?

A: Yes. PS9121-F3-AX operates at 2.7V–3.6V, HCPL-M611-560E at 4.5V–5.5V, and PS9122-F3-AX at 7V. Substitution requires verification that the system power supply can accommodate the substitute part's voltage requirements. Voltage regulators or supply modifications may be necessary.