SMB15F28AY Equivalent & Substitute Parts

Part Overview

The SMB15F28AY is a unidirectional transient voltage suppressor (TVS) diode manufactured by STMicroelectronics, designed for surface mount applications in automotive-grade circuits. This component provides transient overvoltage protection with a 28V reverse standoff voltage and 59V maximum clamping voltage at peak pulse current. The part is classified as obsolete, necessitating identification of active equivalent alternatives that maintain electrical and mechanical compatibility for ongoing production and repair applications.

Substiute Parts

SMB15F28AY

STMicroelectronicsIn Stock: 5960SMB15F28AY Datasheet

Current PartRFQ

SM15T33AY

STMicroelectronicsIn Stock: 3690SM15T33AY Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the SMB15F28AY is based on electrical parameter equivalence within the following criteria:

Critical Matching Parameters:

• Voltage - Reverse Standoff: 28V nominal (tolerance range 28V to 28.2V acceptable)
• Voltage - Clamping (Max) @ Ipp: 59V (exact match required)
• Current - Peak Pulse (8/20µs): 169A (exact match required)
• Power - Peak Pulse: 1500W (exact match required)
• Type: Zener, Unidirectional
• Grade: Automotive with AEC-Q101 qualification
• Mounting Type: Surface Mount

Package Compatibility Consideration: The SMB15F28AY uses DO-221AA (SMBflat) packaging. Substitute parts may use alternative surface mount packages (DO-214AB/SMC) provided the electrical parameters remain equivalent and the mounting footprint is compatible with the application circuit board design.

The SM15T33AY meets all critical electrical parameters and maintains automotive-grade qualification, making it a valid substitute despite package variation and extended operating temperature range differences.

Parameter Comparison

Engineering Selection Recommendations

SM15T33AY as Primary Substitute:

The SM15T33AY is the recommended substitute for the obsolete SMB15F28AY based on the following factors:

1. Electrical Equivalence: All critical electrical parameters match or fall within acceptable tolerance ranges. The clamping voltage (59V), peak pulse current (169A), and power dissipation (1500W) are identical.

2. Automotive Compliance: Both components carry automotive-grade designation with AEC-Q101 qualification, ensuring suitability for automotive applications.

3. Active Product Status: The SM15T33AY is an active product with confirmed inventory availability (3648 pcs), whereas the SMB15F28AY is obsolete.

4. Regulatory Compliance: Both components maintain identical REACH and ECCN classifications, ensuring no regulatory barriers to substitution.

5. Package Consideration: The SM15T33AY uses DO-214AB (SMC) packaging instead of DO-221AA (SMBflat). Circuit board layout and footprint compatibility must be verified before implementation.

6. Operating Temperature Limitation: The SM15T33AY operates within -40°C to 150°C, compared to the original part's -55°C to 175°C range. Applications requiring operation below -40°C or above 150°C require alternative solutions.

Frequently Asked Questions (FAQ)

Q: Can the SM15T33AY directly replace the SMB15F28AY in all applications?

A: Electrical substitution is valid for all applications within the SM15T33AY operating temperature range (-40°C to 150°C). Physical package differences (DO-214AB/SMC vs. DO-221AA/SMBflat) require circuit board footprint verification. Applications requiring operation below -40°C or above 150°C require alternative components.

Q: What are the key electrical parameters that define substitution compatibility?

A: Substitution compatibility is determined by matching: reverse standoff voltage (28V nominal), clamping voltage (59V), peak pulse current (169A at 8/20µs), and power dissipation (1500W). All these parameters are identical between the SMB15F28AY and SM15T33AY.

Q: Why does the SM15T33AY have a different operating temperature range?

A: The SM15T33AY operates from -40°C to 150°C junction temperature, whereas the SMB15F28AY operates from -55°C to 175°C. This difference reflects the thermal characteristics of the different package types (SMC vs. SMBflat). Applications operating at the temperature extremes of the original part require thermal analysis or alternative component selection.

Q: Are there any regulatory or compliance differences between these parts?

A: No. Both components maintain identical REACH, ECCN (EAR99), and automotive-grade AEC-Q101 qualifications. Regulatory substitution is unrestricted.

Q: What is the primary consideration when switching from SMBflat to SMC packaging?

A: The primary consideration is circuit board layout compatibility. The SMBflat (DO-221AA) and SMC (DO-214AB) packages have different footprints and lead configurations. The PCB design must accommodate the SMC package dimensions and lead spacing before implementation.

Q: Is the SM15T33AY available in the same packaging as the SMB15F28AY?

A: No. The SM15T33AY uses DO-214AB (SMC) packaging, while the SMB15F28AY uses DO-221AA (SMBflat) packaging. Both are surface mount packages with equivalent electrical performance but different physical dimensions and footprints.

Q: What inventory status should be considered for production planning?

A: The SMB15F28AY is obsolete with 5886 pcs in stock. The SM15T33AY is an active product with 3648 pcs in stock. For new designs and ongoing production, the SM15T33AY should be specified to ensure long-term component availability.