Taiwan Semiconductor Corporation SA54C

Overview

SA54C from Taiwan Semiconductor is a unidirectional 54 V working stand-off transient voltage suppressor (TVS) diode in DO-204AC (DO-15) package, rated for 500 W peak pulse power at 10/1000 μs, with 60.0–73.3 V breakdown voltage at 1 mA test current and 86.3 V maximum clamping voltage at 5.4 A peak pulse current; used for ESD and lightning surge protection in automotive power supplies and industrial control inputs.

For engineers reviewing the SA54C datasheet, SA54C pinout, SA54C application, or SA54C equivalent, key selection criteria include clamping voltage margin relative to protected IC V_DD, leakage current below 1 μA at 54 V, unidirectional polarity marking, DO-15 thermal derating above 25°C, and AEC-Q101 qualification status verification.

Technical Context

The SA54C operates as a silicon avalanche diode that enters controlled reverse breakdown during overvoltage transients, diverting surge current away from downstream circuitry while maintaining clamped voltage below 86.3 V at 5.4 A. Its 1 mA breakdown test current and 54 V stand-off rating define its placement before DC-DC input stages or microcontroller I/O lines.

It exhibits <1.0 ps response time from 0 V to V_BR, low dynamic impedance under surge, and thermal stability up to 175°C junction temperature. The device is not bidirectional-cathode band marking indicates polarity, and forward conduction is limited to 3.5 V at 35 A per absolute maximum ratings.

Key Specifications

Pinout & Package

Package: DO-204AC (DO-15), axial leaded, epoxy-molded case with UL 94V-0 flammability rating and pure tin-plated leads compliant with J-STD-002 solderability. Cathode indicated by band marking; anode and cathode terminals are non-reversible for unidirectional operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ54A and P6KE56A, the SA54C offers lower clamping voltage (86.3 V vs. ≥93.6 V) and tighter V_BR range (60.0–73.3 V), making it preferable for protecting 100 V-rated components where voltage margin is constrained, while retaining DO-15 through-hole compatibility and AEC-Q101 availability in CH variant.

Availability

SA54C is available at Aetrix Electronics and suitable for automotive power input protection, industrial PLC analog input protection, and LED driver overvoltage clamp applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for SA54C 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, rectifiers, and MOSFETs for industrial, automotive, and consumer markets.

The SA Series TVS diodes are engineered for high-energy transient suppression in harsh environments, with emphasis on AEC-Q101 qualification, tight parameter distribution, and robust DO-15 packaging for reliability-critical power and interface protection.

FAQ

What is the maximum clamping voltage of the SA54C under standard 10/1000 μs surge conditions?

The SA54C has a maximum clamping voltage (V_C) of 86.3 V at 5.4 A peak pulse current under the 10/1000 μs waveform. This value is measured per ANSI/IEEE C62.35 and defines the upper voltage limit imposed on protected circuitry during a standardized surge event. Designers must verify this clamping level remains below the absolute maximum rating of downstream components. The SA54C achieves this performance while maintaining 54 V working stand-off and sub-1 ps response.

Is the SA54C unidirectional or bidirectional, and how is polarity identified?

The SA54C is a unidirectional TVS diode, designed for DC line protection with defined anode and cathode terminals. Polarity is marked by a cathode band on the DO-204AC (DO-15) package body. When installed, the cathode connects to the line being protected (e.g., +54 V rail), and the anode connects to ground or return. Bidirectional variants in the SA series use "CA" suffix (e.g., SA54CA), which the SA54C does not carry.

Does the SA54C meet AEC-Q101 qualification, and what does that mean for automotive use?

The base SA54C is not AEC-Q101 qualified; however, the SA54CH variant (with "H" suffix) is explicitly qualified per AEC-Q101 for automotive applications. AEC-Q101 certification confirms the device passes stress tests including high-temperature operating life, temperature cycling, and mechanical shock-required for under-hood and chassis-mounted modules. For automotive designs, specify SA54CH to ensure compliance; SA54C alone lacks this validation.

What is the reverse leakage current of the SA54C at its rated working voltage?

The SA54C exhibits reverse leakage current (I_R) of less than 1 μA at its 54 V working stand-off voltage (V_WM). This low leakage is confirmed per the manufacturer's electrical characteristics table and is critical for battery-powered or low-quiescent-current systems where cumulative leakage could impact standby power budget. The specification holds at T_A = 25°C and is derated at elevated temperatures per the published thermal curves.

How does the SA54C's 500 W peak pulse power rating translate to real-world surge handling capability?

The SA54C's 500 W rating is specified for a single 10/1000 μs exponential surge waveform, representing a standardized lightning-induced or inductive-switching transient. In practice, this enables the SA54C to safely clamp surges up to 5.4 A peak current while limiting voltage to 86.3 V. Repetitive surges require derating per the published pulse derating curve (Fig.2), and sustained power dissipation is limited to 3 W at 75°C lead temperature-critical for thermal design in enclosed enclosures.