SMA6F20AY Equivalent & Substitute Parts

Part Overview

The SMA6F20AY 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 20V reverse standoff voltage and provides transient protection with a 32.4V maximum clamping voltage at peak pulse current of 19.4A. The part is classified as Last Time Buy, indicating discontinuation from active production. Equivalent and substitute parts are necessary to ensure continued availability for new designs, production continuity, and long-term component sourcing strategies.

Substiute Parts

SMA6F20AY

STMicroelectronicsIn Stock: 966SMA6F20AY Datasheet

Current PartRFQ

SM6F20AY

STMicroelectronicsIn Stock: 935SM6F20AY Datasheet

MFR RecommendedRFQ

SMA6T24AY

STMicroelectronicsIn Stock: 5916SMA6T24AY Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SMA6F20AY is determined by electrical and mechanical compatibility across the following critical parameters:

Electrical Compatibility Criteria:

• Voltage - Reverse Standoff (Typ): 20V nominal operation
• Voltage - Breakdown (Min): Minimum 22.2V threshold
• Voltage - Clamping (Max) @ Ipp: Maximum clamping voltage under peak pulse conditions
• Current - Peak Pulse: Peak pulse current handling capability
• Power - Peak Pulse: 600W dissipation capacity
• Unidirectional Channels: Single channel configuration

Mechanical Compatibility Criteria:

• Mounting Type: Surface Mount
• Grade: Automotive
• Qualification: AEC-Q101 compliance
• Operating Temperature Range: -55°C to 175°C minimum

Substitute Parts Identified:

1. SM6F20AY (MFR Recommended): Maintains 20V reverse standoff voltage and 600W peak pulse power. Differs in package format (SOD-128 vs. SMAflat) and peak pulse current specification (93A at 8/20µs vs. 19.4A at 10/1000µs). Clamping voltage increases to 42.8V.

2. SMA6T24AY (Similar): Maintains automotive grade and AEC-Q101 qualification. Reverse standoff voltage increases to 20.5V with clamping voltage of 42.8V. Peak pulse current rated at 93A (8/20µs). Package format is DO-214AC (SMA), matching the original SMAflat lead style more closely than SM6F20AY.

Parameter Comparison

Engineering Selection Recommendations

For SMA6F20AY Replacement:

SM6F20AY Selection Criteria: This part is designated as the manufacturer-recommended substitute. It maintains electrical compatibility with identical reverse standoff voltage (20V) and peak pulse power rating (600W). The part is in Active product status, ensuring long-term availability. AEC-Q101 automotive qualification and -55°C to 175°C operating temperature range provide equivalent environmental performance. The primary design consideration is package format transition from SMAflat (DO-221AC) to SOD-128Flat, which requires PCB layout modification. Peak pulse current specification differs due to measurement standard variation (8/20µs vs. 10/1000µs), with SM6F20AY rated at 93A. Clamping voltage increases to 42.8V, providing enhanced transient suppression margin.

SMA6T24AY Selection Criteria: This part offers package compatibility closer to the original SMA6F20AY, utilizing DO-214AC (SMA) format with minimal PCB redesign. Active product status ensures availability. AEC-Q101 qualification and automotive grade maintain compliance requirements. Reverse standoff voltage increases marginally to 20.5V, and clamping voltage reaches 42.8V. Operating temperature range is -40°C to 150°C, which is narrower than the original -55°C to 175°C specification. This part is suitable for applications where the reduced temperature range is acceptable and package footprint compatibility is prioritized.

Compliance Verification: Both substitute parts maintain REACH Unaffected status, EAR99 export classification, and identical HTSUS coding. Both are AEC-Q101 qualified for automotive applications. Selection between SM6F20AY and SMA6T24AY depends on PCB layout constraints and operating temperature requirements specific to the application.

Frequently Asked Questions (FAQ)

Q: Can SM6F20AY directly replace SMA6F20AY without PCB modification?

A: No. SM6F20AY uses SOD-128Flat package format, while SMA6F20AY uses DO-221AC SMAflat leads. PCB footprint and land pattern modifications are required. SMA6T24AY offers closer package compatibility with DO-214AC (SMA) format.

Q: What is the difference between the peak pulse current ratings (19.4A vs. 93A)?

A: The ratings use different measurement standards. SMA6F20AY specifies 19.4A at 10/1000µs pulse duration, while SM6F20AY and SMA6T24AY specify 93A at 8/20µs pulse duration. These are not directly comparable values; they reflect different test conditions defined by the respective datasheets.

Q: Why does the clamping voltage increase from 32.4V to 42.8V in the substitute parts?

A: The substitute parts (SM6F20AY and SMA6T24AY) are designed with higher clamping voltage characteristics. This provides additional transient suppression margin and is compatible with the 20V reverse standoff voltage class. Circuit designs must verify that the higher clamping voltage does not exceed component voltage ratings downstream.

Q: Is SMA6T24AY suitable for applications requiring -55°C operation?

A: No. SMA6T24AY operates from -40°C to 150°C (TJ), which does not meet the -55°C minimum of the original SMA6F20AY. Applications requiring -55°C operation must use SM6F20AY, which maintains the -55°C to 175°C range.

Q: Are both substitute parts AEC-Q101 qualified?

A: Yes. Both SM6F20AY and SMA6T24AY carry AEC-Q101 automotive qualification, matching the original SMA6F20AY specification.

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

A: SMA6F20AY (original) has 909 pieces in stock with Last Time Buy status. SM6F20AY has 866 pieces in stock and is Active. SMA6T24AY has 5860 pieces in stock and is Active. For long-term sourcing, Active status parts are preferred.

Q: Can I use SMA6T24AY if my application does not require the full -55°C to 175°C temperature range?

A: Yes, provided the application operating temperature falls within -40°C to 150°C (TJ). Verify that the higher clamping voltage (42.8V vs. 32.4V) is acceptable for downstream components and circuit protection requirements.

Q: Do the substitute parts have the same moisture sensitivity level?

A: SMA6F20AY and SMA6T24AY both specify MSL 1 (Unlimited). SM6F20AY does not specify MSL in the provided data. Consult the SM6F20AY datasheet for moisture sensitivity classification if this parameter is critical for your application.