Taiwan Semiconductor Corporation SMA4S36AH

Overview

SMA4S36AH from Taiwan Semiconductor is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode with a 36V working stand-off voltage, 40.2–44.5V breakdown voltage at 1mA, and 58.4V clamping voltage at 6.8A peak pulse current; it is AEC-Q101 qualified for automotive power rail protection in BLDC motor drives and battery management systems.

For engineers reviewing the SMA4S36AH datasheet, SMA4S36AH pinout, SMA4S36AH application, or SMA4S36AH equivalent, key selection criteria include its SOD-128 package thermal performance (R_θJL = 20°C/W), unidirectional polarity, 175°C max junction temperature, and compliance with JESD201 Class 2 whisker resistance and RoHS/halogen-free standards.

Technical Context

This TVS diode operates as a unidirectional overvoltage clamp on DC power lines, leveraging glass-passivated junction technology to sustain repetitive 10/1000μs surge events up to 400W without degradation. Its low leakage (<1μA at 36V) and tight V_BR tolerance (±5.5%) support stable protection in high-reliability automotive subsystems.

The device's thermal design centers on low R_θJL (20°C/W) and R_θJC (16°C/W), enabling effective heat transfer from junction to lead and case when mounted on a 5mm × 5mm copper pad - critical for sustained operation under intermittent surge loads in compact PCB layouts.

Key Specifications

Pinout & Package

Package: SOD-128 - Surface-mount, flat-lead, molded plastic case with cathode band marking; meets UL 94V-0 flammability and JESD201 Class 2 whisker resistance requirements.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar transient suppression applications.

Compared with SMAJ36A and SMBJ36A, the SMA4S36AH offers tighter V_BR control and superior thermal resistance in the smaller SOD-128 package - advantageous for space-constrained automotive modules requiring precise clamping and high-temperature reliability.

Availability

SMA4S36AH is available at Aetrix Electronics and suitable for BLDC motor drives, battery management systems, automotive lighting modules, and switching mode power supplies requiring stable component supply with AEC-Q101 assurance and halogen-free compliance.

Supply support for SMA4S36AH 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

Taiwan Semiconductor Corporation (TSC) is a vertically integrated analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, specializing in TVS diodes, rectifiers, MOSFETs, and power management devices.

The SMA4SxxAH series was developed specifically for automotive-grade transient suppression in space-limited, thermally demanding environments - emphasizing AEC-Q101 qualification, tight parametric control, and robust thermal performance in the SOD-128 package.

FAQ

What is the maximum clamping voltage of the SMA4S36AH under standard test conditions?

The SMA4S36AH has a maximum clamping voltage (V_C) of 58.4 V when subjected to a 10/1000 μs waveform peak pulse current (I_PPM) of 6.8 A at T_A = 25°C. This value is measured per JEDEC standards and reflects the device's ability to limit transient voltage across protected circuitry - a critical parameter for ensuring downstream IC survival during surge events. The SMA4S36AH maintains this clamping performance across its specified junction temperature range.

Is the SMA4S36AH suitable for automotive applications?

Yes, the SMA4S36AH is AEC-Q101 qualified and explicitly designed for automotive use cases including BLDC motor drives, lighting modules, and battery management systems. It meets stringent reliability requirements such as temperature cycling, high-temperature reverse bias (HTRB), and mechanical robustness testing. Its 175°C maximum junction temperature, unidirectional polarity, and SOD-128 package with matte tin leads further support under-hood deployment - all confirmed in Taiwan Semiconductor's official qualification report for the SMA4SxxAH family.

What is the polarity configuration of the SMA4S36AH?

The SMA4S36AH is a unidirectional TVS diode, meaning it functions as a reverse-biased clamp - conducting only when the cathode is at a higher potential than the anode. This configuration protects against positive-going transients on DC power lines referenced to ground. The cathode band on the SOD-128 package provides clear visual polarity identification, and the device must be oriented accordingly on the PCB to ensure proper protection function. Forward voltage is specified at 3.5 V @ 25 A, though forward conduction is not its primary operational mode.

Does the SMA4S36AH require moisture sensitivity handling before reflow soldering?

No, the SMA4S36AH has a moisture sensitivity level (MSL) of 1 per J-STD-020, meaning it may be stored indefinitely at ambient conditions (≤30°C/60% RH) without baking or dry-packing requirements. This eliminates pre-reflow bake steps and simplifies manufacturing logistics - particularly beneficial for high-volume automotive electronics production where process efficiency and yield consistency are critical. The MSL-1 rating is verified through standardized preconditioning and saturation testing per industry standard.

What thermal resistance values are specified for the SMA4S36AH in its recommended mounting configuration?

The SMA4S36AH specifies R_θJL = 20°C/W (junction-to-lead), R_θJC = 16°C/W (junction-to-case), and R_θJA = 62°C/W (junction-to-ambient), all measured with the device mounted on a 5 mm × 5 mm copper pad per JEDEC test board guidelines. These values enable accurate thermal modeling for surge duty-cycle analysis and ensure safe operation within the 175°C maximum junction temperature limit. The low R_θJL is especially valuable for transferring heat directly into PCB copper planes without additional heatsinking.