Diodes Incorporated SD1A150E

Overview

SD1A150E from Littelfuse (formerly LSC) is a unidirectional SIDAC thyristor designed for controlled high-voltage triggering in gas igniter circuits, featuring a 142–157 Vdc breakover voltage (VBO), 120 V peak repetitive off-state voltage (VDRM), and 1 A RMS on-state current rating in a DO-41 package.

For engineers reviewing the SD1A150E datasheet, SD1A150E pinout, SD1A150E application, or SD1A150E equivalent, key selection criteria include verified breakover voltage tolerance, holding current ≤60 mA, di/dt capability ≥80 A/μs, thermal resistance of 15 °C/W, and RoHS-compliant lead-free plating for ignition reliability in compact consumer and appliance designs.

Technical Context

The SD1A150E operates as a two-terminal, voltage-triggered switching device with no gate control-conduction initiates when applied voltage exceeds its temperature-dependent VBO range (142–157 V at 25°C). It latches on until current falls below the holding threshold (IH ≤ 60 mA).

Its DO-41 package enables direct PCB mounting in space-constrained igniter assemblies, and its 80 A/μs critical rate of rise of on-state current ensures robust turn-on without false triggering under fast-rising transients common in piezoelectric or capacitive discharge ignition systems.

Key Specifications

Pinout & Package

DO-41 molded plastic package with axial leads; RoHS-compliant lead-free plating; case conforms to JEDEC DO-41 mechanical standard.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar unidirectional SIDAC triggering applications.

Compared with SD1A150D and K2000E, the SD1A150E offers optimal balance of VBO centering at 150 V, lowest thermal resistance, and smallest DO-41 footprint-making it ideal for new compact gas igniter designs requiring high production yield and thermal headroom.

Availability

SD1A150E is available at Aetrix Electronics and suitable for gas igniters, appliance safety controls, portable propane heaters, and commercial kitchen igniters requiring stable component supply with tight VBO tolerance and RoHS compliance.

Supply support for SD1A150E 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

Littelfuse (acquired LSC Semiconductor) is a global leader in circuit protection, power control, and sensing technologies, specializing in high-reliability discrete semiconductors for harsh-environment applications.

The SD1A150E belongs to Littelfuse's SIDAC family engineered specifically for contactless, voltage-triggered ignition in gas-fired appliances-emphasizing precision VBO control, thermal stability, and long-term parametric consistency.

FAQ

What is the maximum allowable junction temperature for continuous operation?

The SD1A150E has an operating junction temperature range of −40°C to +125°C. For continuous RMS current at 1 A, thermal design must ensure junction temperature remains ≤125°C, considering RthJC = 15 °C/W and ambient conditions. Derating is required above 80°C case temperature per the IT(RMS) curve in Fig.2.

Can SD1A150E replace a standard DIAC in AC phase-control circuits?

No-SD1A150E is unidirectional and lacks symmetrical breakover characteristics. It conducts only from anode to cathode and cannot trigger TRIACs in bidirectional AC applications. Use bidirectional DIACs like DB3 or NTE6408 for phase-control dimmers or motor speed controllers.

Is the SD1A150E compatible with lead-free reflow soldering processes?

Yes-the device features lead-free plating and is rated for maximum lead solder temperature of 260°C for 10 seconds. It meets JEDEC J-STD-020 moisture sensitivity level (MSL) requirements for standard reflow profiles, including peak temperatures up to 260°C.

How does junction temperature affect breakover voltage performance?

VBO decreases linearly with rising junction temperature: Fig.3 shows VBO(TJ)/VBO(25°C) ratio drops to ~0.92 at +125°C. At 125°C, VBO shifts from 150 V to approximately 138 V-designers must verify system voltage margins remain sufficient across full operating temperature range.