Taiwan Semiconductor Corporation SA28

Overview

SA28 from Taiwan Semiconductor is a unidirectional 500W transient voltage suppressor (TVS) diode in DO-204AC (DO-15) package, with 28V working stand-off voltage (VWM), 31.1–38.0V breakdown voltage (VBR @ 1mA), and 48.4V clamping voltage (VC) at 10A peak pulse current. It delivers fast response (<1.0ps), low leakage (<1μA @ 28V), and AEC-Q101 qualification for automotive-grade surge protection.

For engineers reviewing the SA28 datasheet, SA28 pinout, SA28 application, or SA28 equivalent, this device is selected for high-reliability DC power rail and signal line protection where precise VWM margin, sub-50V clamping under 10A transients, and automotive temperature range (−55°C to +175°C) are required.

Technical Context

The SA28 operates as a unidirectional avalanche diode, triggered when reverse voltage exceeds its specified VBR range (31.1–38.0V at 1mA). Its clamping action limits transient energy to ≤48.4V at 10A (10/1000μs waveform), enabling robust protection of downstream ICs without latch-up or thermal runaway.

Designed for single-polarity DC systems, it features low dynamic impedance and <1μA reverse leakage above 28V, ensuring minimal standby power loss. The DO-204AC package supports lead-free soldering per J-STD-002 and meets UL 94V-0 flammability rating.

Key Specifications

Pinout & Package

DO-204AC (DO-15) axial-leaded package with cathode band marking for polarity identification. Leads are pure tin-plated and solderable per J-STD-002; case meets UL 94V-0 flammability rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SA28, SMAJ28A offers bidirectional capability in a surface-mount package but requires layout change and may over-clamp in unidirectional systems; P6SMB28A provides higher 600W rating and lower VC in SMB form, yet occupies more area than DO-15 - SA28 remains optimal for cost-sensitive, through-hole automotive and industrial designs requiring exact 28V standoff and proven AEC-Q101 compliance.

Availability

SA28 is available at Aetrix Electronics and suitable for automotive power rail protection, industrial sensor interface protection, and DC-DC converter input protection requiring stable component supply and full traceability.

Supply support for SA28 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 automotive, industrial, and consumer markets.

The SA Series was developed specifically for high-reliability transient suppression in harsh environments, emphasizing AEC-Q101 qualification, wide VWM range (5–170V), and consistent 500W surge capability in DO-15 packaging.

FAQ

What is the breakdown voltage range for SA28?

The SA28 has a minimum breakdown voltage (VBR) of 31.1 V and a maximum of 38.0 V, measured at 1 mA test current per ANSI/IEEE C62.35. This range ensures consistent avalanche triggering across production lots while allowing design margin above the 28 V working stand-off voltage. The SA28's VBR tolerance directly impacts clamping predictability in real-world surge events.

Is SA28 suitable for automotive applications?

Yes, SA28 is AEC-Q101 qualified and rated for operation from −55°C to +175°C, making it suitable for under-hood and body-control module applications. Its DO-204AC package passes JESD201 Class 2 whisker testing and tin-plated leads meet J-STD-002 solderability standards - all verified per TSC's L2105 specification release. SA28 meets ISO 7637-2 Pulse 1 and 5a immunity requirements when applied per layout guidelines.

What is the clamping voltage of SA28 at its rated peak pulse current?

The SA28 clamps to a maximum of 48.4 V at 10 A peak pulse current (IPPM), using the standard 10/1000 μs double-exponential waveform. This value is guaranteed across temperature and lot variations, and defines the upper voltage limit imposed on protected circuitry during surge events. Designers use this VC value to verify that downstream components remain within absolute maximum ratings.

Does SA28 have bidirectional capability?

No, SA28 is a unidirectional TVS diode, indicated by the absence of "CA" or "C" suffix and confirmed by its cathode-band marking and single-polarity electrical characteristics. Bidirectional variants (e.g., SA28CA) exist in the same SA Series but are distinct orderable parts. Using SA28 in bidirectional circuits risks failure during positive transients on the anode side.

What package type does SA28 use and what are its key mechanical properties?

SA28 uses the DO-204AC (DO-15) axial-leaded package, with pure tin-plated leads compliant with J-STD-002, UL 94V-0 molding compound, and a typical weight of 0.400 g. Its polarity is marked by a cathode band, and it meets JESD201 Class 2 whisker resistance. This through-hole package supports high-power dissipation in legacy and high-reliability designs where lead strength and thermal mass matter.