PS9121-A Optoisolator Equivalent & Substitute Parts

Part Overview

The PS9121-A 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 an open collector output, single channel configuration, and operates across a -40°C to 85°C temperature range in a 5-SO surface mount package.

The PS9121-A is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications currently utilizing this component.

Substiute Parts

PS9121-A

CELIn Stock: 2453PS9121-A Datasheet

Current PartRFQ

HCPL-060L

Broadcom LimitedIn Stock: 3429HCPL-060L Datasheet

DirectRFQ

HCPL-M611-560E

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

SimilarRFQ

PS9122-F3-AX

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

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the PS9121-A optoisolator is determined by the following critical parameters:

Primary Compatibility Criteria:

• Isolation voltage: 3750Vrms (all substitutes maintain this specification)
• Number of channels: 1 (single channel configuration required)
• Input type: DC logic input
• Output type: Open collector topology
• Package type: 5-SO or 6-SOIC surface mount (5 leads)
• Operating temperature range: -40°C to 85°C minimum

Secondary Performance Criteria:

• Common mode transient immunity (CMTI): 15kV/µs or higher
• Data rate: 15Mbps or higher
• Output current capability: 25 mA or higher
• Supply voltage compatibility: 2.7V ~ 3.6V or broader range

The substitute parts are grouped into two categories based on their alignment with these parameters:

Direct Substitute (HCPL-M611-560E): Maintains identical package format (5-SO), isolation voltage, channel count, and output type. Meets CMTI and data rate requirements with active product status and RoHS3 compliance.

Compatible Substitute (HCPL-060L): Provides equivalent electrical performance with enhanced output current capability (50 mA) and Schottky clamped output. Uses 8-SO package variant with taller profile. Maintains isolation voltage, channel count, and DC input type.

Functional Substitute (PS9122-F3-AX): Shares identical package format (5-SO), isolation voltage, and channel configuration. Maintains 15kV/µs CMTI matching the original part. Data rate reduced to 1Mbps with extended temperature range to 100°C.

Parameter Comparison

Engineering Selection Recommendations

HCPL-M611-560E Selection Criteria:

Select HCPL-M611-560E when direct package compatibility and identical pinout are required. This part maintains the 5-SO package format matching the PS9121-A footprint. HCPL-M611-560E holds active product status with ROHS3 compliance, ensuring long-term availability and regulatory alignment. The 10kV/µs CMTI specification is lower than the original 15kV/µs; applications requiring the full 15kV/µs transient immunity should evaluate circuit-level mitigation or select PS9122-F3-AX. Supply voltage is limited to 4.5V ~ 5.5V, requiring verification against original 2.7V ~ 3.6V designs. Data rate of 10MBd supports applications up to 10Mbps; designs requiring 15Mbps operation should confirm margin requirements.

HCPL-060L Selection Criteria:

Select HCPL-060L when enhanced output current capability (50 mA versus 25 mA) and Schottky clamped output characteristics provide circuit advantages. This part maintains 3750Vrms isolation and 15MBd data rate performance. The 8-SO package uses a taller profile (8-SOIC, 0.154" width) compared to the original 5-SO format; PCB layout and assembly equipment compatibility must be verified. HCPL-060L offers dual supply voltage support (2.7V ~ 3.6V and 4.5V ~ 5.5V), providing flexibility for mixed-voltage systems. Active product status and broad inventory availability support production continuity. RoHS non-compliance status requires evaluation against regulatory requirements for the end application.

PS9122-F3-AX Selection Criteria:

Select PS9122-F3-AX when package footprint compatibility and 15kV/µs CMTI matching are critical design requirements. This part maintains identical 5-SO package format and pinout with the PS9121-A. PS9122-F3-AX provides 15kV/µs CMTI specification matching the original part exactly. Extended operating temperature range (-40°C to 100°C) supports applications requiring higher temperature operation. Data rate is reduced to 1Mbps; this part is suitable for low-speed isolation applications only. Supply voltage is fixed at 7V, requiring circuit redesign if original 2.7V ~ 3.6V operation is required. ROHS3 compliance and active product status ensure regulatory alignment and supply availability. Output current of 20 mA is lower than the original 25 mA specification; load requirements must be verified.

Frequently Asked Questions (FAQ)

Q: Can HCPL-M611-560E be used as a direct drop-in replacement for PS9121-A?

A: HCPL-M611-560E shares the identical 5-SO package format and pinout with PS9121-A, enabling direct PCB placement compatibility. However, three electrical parameters differ: CMTI is reduced from 15kV/µs to 10kV/µs, data rate is reduced from 15Mbps to 10MBd, and supply voltage range is 4.5V ~ 5.5V instead of 2.7V ~ 3.6V. Applications must verify that these parameter changes do not exceed circuit margin requirements.

Q: What is the primary difference between HCPL-060L and the other substitutes?

A: HCPL-060L uses an 8-SO package format instead of the 5-SO format of PS9121-A. This package change requires PCB layout modification and assembly equipment verification. HCPL-060L provides enhanced output current (50 mA) and Schottky clamped output topology, which may improve switching performance in certain applications. The 8-SO package is physically larger, requiring confirmation that board space permits the substitution.

Q: Is PS9122-F3-AX suitable for high-speed applications?

A: PS9122-F3-AX is not suitable for high-speed applications. Data rate is specified at 1Mbps, compared to 15Mbps for PS9121-A. Propagation delay is significantly higher (700ns/500ns versus 75ns/75ns). This part is appropriate only for low-speed isolation applications where data rates do not exceed 1Mbps.

Q: Which substitute part has the best regulatory compliance?

A: Both HCPL-M611-560E and PS9122-F3-AX hold ROHS3 compliance status. HCPL-060L is RoHS non-compliant. For applications requiring RoHS compliance, select either HCPL-M611-560E or PS9122-F3-AX based on electrical performance requirements.

Q: Can HCPL-060L be used in a 2.7V ~ 3.6V supply circuit?

A: HCPL-060L supports dual supply voltage ranges: 2.7V ~ 3.6V and 4.5V ~ 5.5V. This part can operate in 2.7V ~ 3.6V circuits, providing supply voltage flexibility. However, the 8-SO package format requires PCB layout changes compared to the original 5-SO PS9121-A.

Q: What is the inventory status of these substitute parts?

A: HCPL-M611-560E has 4017 pieces in stock. HCPL-060L has 3400 pieces in stock. PS9122-F3-AX has 18342 pieces in stock. All three substitutes are available as new original components.

Q: Are there any temperature range limitations when substituting?

A: PS9121-A operates from -40°C to 85°C. HCPL-M611-560E and HCPL-060L maintain this identical range. PS9122-F3-AX extends the upper limit to 100°C, supporting higher temperature applications. Applications requiring operation above 85°C should select PS9122-F3-AX; applications limited to 85°C maximum can use any substitute.

Q: What output current capability should be considered for substitution?

A: PS9121-A specifies 25 mA output current per channel. HCPL-M611-560E provides 50 mA, offering increased drive capability. HCPL-060L also provides 50 mA. PS9122-F3-AX provides 20 mA, which is lower than the original specification. Applications with output current requirements exceeding 20 mA should avoid PS9122-F3-AX. Applications with requirements below 20 mA can use any substitute.