Taiwan Semiconductor Corporation SMA4F47AH

Overview

SMA4F47AH from Taiwan Semiconductor is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode with a 47V working stand-off voltage, 52.5–58.1V breakdown voltage at 1mA, and 76.3V clamping voltage at 5.2A peak pulse current; it is AEC-Q101 qualified and used in automotive battery management systems and BLDC motor drives.

For engineers reviewing the SMA4F47AH datasheet, SMA4F47AH pinout, SMA4F47AH application, or SMA4F47AH equivalent, key selection criteria include unidirectional polarity, Thin SMA package thermal performance (R_θJL = 20°C/W), 175°C max junction temperature, and compliance with JESD201 Class 2 whisker resistance and RoHS/halogen-free requirements.

Technical Context

The SMA4F47AH operates as a unidirectional avalanche diode for transient overvoltage protection in DC power rails. Its glass-passivated junction ensures stable V_BR with a temperature coefficient of 0.095%/°C, and its 10/1000μs waveform rating supports 400W non-repetitive peak pulse power dissipation.

Designed for PCB mounting on 5mm × 5mm copper pads, it delivers R_θJA = 62°C/W and R_θJC = 16°C/W thermal performance. The device exhibits 1μA maximum reverse leakage at 47V and 3.5V forward voltage at 25A, confirming robust conduction capability during fault conditions.

Key Specifications

Pinout & Package

Package: Thin SMA - Surface-mount plastic package with matte tin-plated leads, UL 94V-0 rated molding compound, and 0.030g mass. Compliant with J-STD-002 solderability and JESD201 Class 2 whisker testing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ47A and 1.5SMC47A, the SMA4F47AH offers optimized thermal resistance (R_θJL = 20°C/W) and AEC-Q101 qualification in a thinner profile, making it uniquely suited for space-constrained, thermally demanding automotive electronics where consistent low-profile mounting and automotive reliability are mandatory.

Availability

SMA4F47AH is available at Aetrix Electronics and suitable for battery management systems, BLDC motor drives, automotive lighting modules, and switching mode power supplies requiring stable component supply with automotive-grade qualification and thin-profile packaging.

Supply support for SMA4F47AH 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 semiconductor manufacturer specializing in discrete power devices, TVS diodes, and rectifiers with global distribution and AEC-Q101 validation capabilities.

The SMA4FxxAH series was developed specifically for automotive and industrial DC power rail protection, emphasizing thin-profile mounting, high-temperature reliability, and precise clamping performance in compact PCB designs.

FAQ

What is the maximum clamping voltage of the SMA4F47AH under standard surge conditions?

The SMA4F47AH has a maximum clamping voltage (V_C) of 76.3 V when subjected to a 10/1000 μs waveform peak pulse current of 5.2 A. This value is measured at T_A = 25°C and defines the upper voltage limit imposed on protected circuitry during transient events. The SMA4F47AH maintains this clamping performance across its specified junction temperature range, supporting robust overvoltage protection in automotive and industrial applications.

Is the SMA4F47AH suitable for bidirectional transient protection?

No, the SMA4F47AH is a unidirectional TVS diode, designed exclusively for protection against positive-going transients on DC lines. Its cathode-band marking indicates polarity-sensitive placement, and it does not suppress negative excursions. For bidirectional protection, a separate device such as the SMA4F47A (bidirectional variant) or a dual-diode configuration would be required. The SMA4F47AH datasheet explicitly specifies unidirectional polarity in its mechanical data section.

Does the SMA4F47AH require special handling or baking before SMT reflow?

No, the SMA4F47AH has a moisture sensitivity level (MSL) of 1 per J-STD-020, meaning it may be stored indefinitely at ambient conditions without floor life restrictions or pre-reflow baking. Its matte tin-plated leads meet J-STD-002 solderability requirements, and the device is qualified for standard lead-free reflow profiles. This eliminates process overhead in high-volume manufacturing and supports just-in-time assembly workflows.

What is the thermal resistance from junction to ambient for the SMA4F47AH?

The SMA4F47AH has a junction-to-ambient thermal resistance (R_θJA) of 62°C/W when mounted on a standard 5 mm × 5 mm copper pad test board. This value assumes natural convection cooling and is critical for estimating steady-state junction temperature rise under continuous power dissipation. For higher-power or elevated-temperature environments, thermal design should leverage the lower R_θJL = 20°C/W to route heat through leads into internal ground planes.

How does the SMA4F47AH differ from the SMAJ47A in terms of automotive qualification?

The SMA4F47AH is explicitly AEC-Q101 qualified, with full test reports covering HTGB, H3TRB, TC, and ESD per automotive stress requirements. In contrast, the SMAJ47A is not AEC-Q101 certified and lacks formal automotive reliability validation. While both share similar electrical specs, only the SMA4F47AH meets the mandatory qualification for use in automotive electronic control units, battery systems, and motor drives where long-term field reliability is contractually enforced.