SMA4F6.5AY Equivalent & Substitute Parts

Part Overview

The SMA4F6.5AY is a unidirectional transient voltage suppressor (TVS) diode manufactured by STMicroelectronics, designed for surface mount applications in automotive-grade circuits. This component operates with a 6.5V reverse standoff voltage and provides 11.2V maximum clamping voltage at peak pulse current, with a peak pulse power rating of 400W. The device is packaged in DO-221AC SMAflat configuration and meets AEC-Q101 automotive qualification standards.

The SMA4F6.5AY carries a Last Time Buy product status, indicating discontinued production. Identification of equivalent and substitute parts is necessary to maintain design continuity and ensure component availability for ongoing production and field service applications.

Substiute Parts

SMA4F6.5AY

STMicroelectronicsIn Stock: 10219SMA4F6.5AY Datasheet

Current PartRFQ

SM4T7V6AY

STMicroelectronicsIn Stock: 736SM4T7V6AY Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the SMA4F6.5AY is determined by strict alignment of the following electrical and mechanical parameters:

Critical Substitution Parameters:

• Voltage - Reverse Standoff (Typ): 6.5V
• Voltage - Breakdown (Min): 7.2V
• Unidirectional channel configuration (1 channel)
• Automotive Grade classification
• AEC-Q101 qualification
• Surface Mount technology
• Peak Pulse Power rating: 400W
• Moisture Sensitivity Level: 1 (Unlimited)

The SM4T7V6AY qualifies as a substitute part based on matching reverse standoff voltage (6.5V), breakdown voltage (7.2V), unidirectional topology, automotive grade, AEC-Q101 certification, surface mount configuration, and identical peak pulse power rating. Differences in clamping voltage (14.5V vs. 11.2V), peak pulse current specification format (8/20µs vs. 10/1000µs), and package designation (DO-214AC SMA vs. DO-221AC SMAflat) reflect design variations within the same functional class and do not preclude substitution when circuit requirements permit higher clamping voltage performance.

Parameter Comparison

Engineering Selection Recommendations

SMA4F6.5AY (Main Part): The SMA4F6.5AY is classified as Last Time Buy, indicating production discontinuation. This part carries full automotive qualification (AEC-Q101) and operates across an extended temperature range (-55°C to 175°C). Existing inventory of 10,202 pieces is available. Selection of this part is appropriate only for applications with existing design validation and where remaining inventory meets production volume requirements.

SM4T7V6AY (Substitute Part): The SM4T7V6AY maintains Active product status with ongoing manufacturing availability. This part meets identical automotive qualification (AEC-Q101) and core electrical parameters (6.5V reverse standoff, 7.2V breakdown voltage). The substitute operates across -55°C to 150°C, which covers standard automotive temperature requirements. Current inventory of 627 pieces supports immediate procurement. The SM4T7V6AY is suitable for new designs and ongoing production where the higher clamping voltage (14.5V vs. 11.2V) and different peak pulse current specification do not conflict with circuit protection requirements.

Both parts maintain REACH Unaffected status, EAR99 export classification, and identical Moisture Sensitivity Level (MSL 1). Selection between these parts depends on design validation history, temperature range requirements, and circuit-specific clamping voltage tolerance.

Frequently Asked Questions (FAQ)

Q: Can SM4T7V6AY directly replace SMA4F6.5AY in existing designs?

A: Direct replacement requires circuit validation. Both parts share identical reverse standoff voltage (6.5V) and breakdown voltage (7.2V), but differ in clamping voltage (14.5V vs. 11.2V) and package configuration (DO-214AC SMA vs. DO-221AC SMAflat). PCB layout modifications may be necessary due to package differences. Electrical performance differences must be evaluated against circuit protection requirements.

Q: What is the significance of the different peak pulse current specifications?

A: The SMA4F6.5AY specifies 35.7A at 10/1000µs pulse duration, while SM4T7V6AY specifies 160A at 8/20µs pulse duration. These represent different test conditions and pulse waveforms. Both parts maintain identical 400W peak pulse power rating. The specification difference reflects different measurement methodologies rather than direct performance comparison.

Q: Are both parts suitable for automotive applications?

A: Yes. Both the SMA4F6.5AY and SM4T7V6AY carry Automotive Grade classification and AEC-Q101 qualification. Both maintain MSL 1 (Unlimited) moisture sensitivity rating and REACH Unaffected status, meeting automotive supply chain requirements.

Q: What is the impact of the operating temperature range difference?

A: The SMA4F6.5AY operates to 175°C junction temperature, while SM4T7V6AY operates to 150°C. For standard automotive applications operating within -55°C to 150°C, both parts are equivalent. Applications requiring operation above 150°C junction temperature require the SMA4F6.5AY or alternative parts with extended temperature ratings.

Q: How do package differences affect PCB design?

A: The SMA4F6.5AY uses DO-221AC SMAflat package with flat leads, while SM4T7V6AY uses DO-214AC SMA package. These are distinct footprints requiring different PCB land patterns. Existing designs validated for SMAflat configuration require layout modification and re-validation for SMA package substitution.

Q: Why is SMA4F6.5AY classified as Last Time Buy?

A: Last Time Buy status indicates STMicroelectronics has discontinued production of this part number. Existing inventory remains available for purchase, but no future manufacturing is planned. Users should transition to active alternatives such as SM4T7V6AY for long-term supply security.