Taiwan Semiconductor Corporation SA28CH

Overview

SA28CH 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 AEC-Q101 qualification for automotive-grade surge immunity and protects power rails and I/O lines against ESD and inductive switching transients.

For engineers reviewing the SA28CH datasheet, SA28CH pinout, SA28CH application, or SA28CH equivalent, this page provides verified electrical parameters, clamping performance at 10/1000μs waveform, thermal derating behavior, polarity marking, and AEC-Q101 compliance status - all critical for automotive power supply protection and industrial control interface hardening.

Technical Context

The SA28CH operates as a unidirectional avalanche diode, triggered when reverse voltage exceeds its VBR range (31.1–38.0V). Its low dynamic impedance enables rapid clamping to ≤48.4V at 10A IPPM under 10/1000μs surge, limiting energy dissipation in protected circuits. It exhibits <1μA reverse leakage at 28V VWM and a 35mV/°C VBR temperature coefficient.

Designed for single-polarity DC rail protection, it features pure tin-plated leads compliant with J-STD-002, UL 94V-0 molding compound, and JESD201 Class 2 whisker resistance. Its junction operates from –55°C to +175°C, supporting under-hood automotive environments without derating up to 75°C ambient.

Key Specifications

Pinout & Package

DO-204AC (DO-15) package: axial-leaded, molded epoxy case with cathode band marking. Leads are pure tin-plated, solderable per J-STD-002. Polarity is unidirectional; cathode band denotes the terminal connected to circuit ground or return path during clamping.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ28A and P6SMB28AH, SA28CH uniquely combines AEC-Q101 qualification, DO-204AC axial form factor, and 48.4V clamping at 10A - making it the only option validated for automotive power rail protection where through-hole mounting and high-reliability surge immunity are jointly required.

Availability

SA28CH is available at Aetrix Electronics and suitable for automotive electronic control units, industrial sensor interfaces, LED lighting systems, and motor control boards requiring stable component supply with guaranteed AEC-Q101 compliance and long-lifecycle support.

Supply support for SA28CH 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 is TSC's AEC-Q101-qualified transient voltage suppressor family designed specifically for robust overvoltage protection in 12V/24V automotive power networks and harsh industrial environments.

FAQ

What does the "H" suffix in SA28CH signify?

The "H" suffix in SA28CH indicates full AEC-Q101 qualification, confirming that the device has passed stress tests for automotive-grade reliability-including temperature cycling, humidity bias HAST, mechanical shock, and high-temperature operating life. This makes SA28CH suitable for deployment in engine control units, body control modules, and other under-hood or safety-critical automotive systems where standard industrial TVS diodes would not be approved.

Is SA28CH unidirectional or bidirectional, and how is polarity marked?

SA28CH is a unidirectional TVS diode. Polarity is marked by a cathode band on the DO-204AC (DO-15) package body - the banded end connects to system ground or the low-side reference point. This configuration allows it to clamp only negative-going transients on positive rails, matching typical 24V automotive power architecture where the chassis serves as the return path.

What is the maximum clamping voltage of SA28CH under standard test conditions?

The maximum clamping voltage of SA28CH is 48.4 V at 10 A peak pulse current (IPPM), measured using the 10/1000 μs double-exponential surge waveform per IEC 61000-4-5. This value is guaranteed across the full operating temperature range (–55°C to +175°C) and defines the upper voltage limit imposed on protected circuitry during surge events.

Can SA28CH replace SA28A in an existing design?

No - SA28CH and SA28A are not interchangeable. SA28CH is AEC-Q101 qualified and rated for automotive use, while SA28A lacks that qualification and has different clamping performance (VC = 59.0 V @ 11.5 A). Substituting SA28A for SA28CH risks non-compliance with automotive functional safety requirements and may result in insufficient protection margin during load-dump events.

What is the junction-to-ambient thermal resistance (RθJA) for SA28CH in standard mounting?

Taiwan Semiconductor does not publish RθJA for SA28CH in the SA Series datasheet. Thermal performance is specified via steady-state power dissipation: 3 W at TL = 75°C with 9.5 mm lead lengths mounted on 10 × 10 mm copper pads. For thermal modeling, users should apply JEDEC JESD51-2A guidelines and validate junction temperature using the given derating curve (Fig.2) and actual PCB copper area.