STMicroelectronics SMA6T36AY

Overview

SMA6T36AY from STMicroelectronics is a unidirectional 600 W automotive-grade transient voltage suppressor (TVS) diode designed for ISO 7637-2 pulse protection in 12 V/24 V vehicle power networks. It features a 36 V breakdown voltage (V_BR = 30.8–37.8 V), 49.9 V clamping voltage at 12 A (10/1000 µs), and ≤0.2 µA leakage at 25 °C - enabling robust surge immunity in engine control units, body electronics, and infotainment power rails.

For engineers reviewing the SMA6T36AY datasheet, SMA6T36AY pinout, SMA6T36AY application, or SMA6T36AY equivalent, key selection criteria include its AEC-Q101 qualification, 150 °C junction temperature rating, JEDEC DO-214AC (SMA) package compatibility, and verified performance against ISO 10605 ±30 kV ESD and ISO 7637-2 Pulse 1/2a/3a/3b transients.

Technical Context

This TVS operates as a clamping device in parallel with sensitive loads, activating above its reverse standoff voltage (V_RWM = 30.8 V) to divert surge current while limiting voltage to ≤49.9 V at 12 A (10/1000 µs). Its planar silicon junction ensures low dynamic resistance (R_D = 1.06 Ω) and stable V_BR temperature coefficient (α_T = 9.9 × 10⁻⁴/°C).

It meets stringent automotive reliability requirements: MSL Level 1 moisture sensitivity, JESD22-B102 E3 solderability, IPC7531 footprint compliance, and whisker resistance per JESD201 Class 2 - all validated under −55 °C to +150 °C operating junction range.

Key Specifications

Pinout & Package

Supplied in JEDEC DO-214AC (SMA) surface-mount package with matte tin-plated leads, compliant with IPC7531 footprint and RoHS/ECOPACK2 environmental standards. Dimensions: 4.80–5.35 mm × 2.25–2.90 mm × 1.90–2.45 mm (L × W × H).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar unidirectional TVS diode applications.

Compared with SMA6T36A, the SMA6T36AY adds full AEC-Q101 traceability and high-temperature reliability data; compared with SMCJ36A, it trades surge capacity for compact SMA packaging - making it optimal for space-constrained automotive ECUs requiring certified robustness.

Availability

SMA6T36AY is available at Aetrix Electronics and suitable for engine control units, body control modules, infotainment head units, and ADAS camera power supplies requiring stable component supply across automotive production lifecycles.

Supply support for SMA6T36AY includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power management solutions with broad manufacturing and quality certification infrastructure.

The SMA6TY series belongs to ST's Transil™ automotive TVS portfolio, engineered specifically to meet OEM requirements for ISO 7637-2 and ISO 10605 transient immunity in 12 V/24 V vehicle electrical architectures.

FAQ

What is the maximum clamping voltage of SMA6T36AY under ISO 7637-2 Pulse 1 conditions?

The SMA6T36AY clamps to ≤49.9 V at 12 A (10/1000 µs waveform), which directly covers ISO 7637-2 Pulse 1 (−150 V, 50 Ω source impedance). Measured V_CL remains stable up to 150 °C junction temperature due to its 9.9 × 10⁻⁴/°C temperature coefficient, ensuring consistent protection during sustained engine heat exposure.

Can SMA6T36AY be used in bidirectional signal line protection?

No - SMA6T36AY is unidirectional and must be connected with cathode toward the protected line. For bidirectional protection (e.g., CAN bus lines), ST offers the pin-compatible SMA6T36CAY variant, which provides symmetrical clamping in both polarities and is marked with "6BPY" on the package body.

Does SMA6T36AY require derating at elevated ambient temperatures?

Yes - its 600 W peak pulse power is specified at T_j = 25 °C. Derating follows Figure 3 in DS6931: at 125 °C initial junction temperature, maximum pulse power drops to ~65% (≈390 W). Layout must ensure thermal resistance to ambient ≤4.5 °C/W using ≥1 cm² copper per lead to maintain rating at high T_amb.

How does the dynamic resistance (R_D = 1.06 Ω) impact system-level surge protection design?

The 1.06 Ω dynamic resistance determines voltage overshoot beyond V_BR during surge events: V_CL = V_BR + R_D × I_PP. At 12 A, this contributes 12.7 V of resistive drop - critical for verifying that total clamped voltage stays below the absolute maximum rating of downstream ICs such as automotive MCUs rated for 50 V max input.