Diodes Incorporated SD1A200G

Overview

SD1A200G from Littelfuse (formerly LSC) is a unidirectional SIDAC thyristor designed for high-voltage, low-current trigger applications in gas igniters. It features a 190–210 Vdc breakover voltage (VBO), 170 V peak repetitive off-state voltage (VDRM), 1 A RMS on-state current rating, and ≤60 mA holding current (IH), operating across –40°C to +125°C junction temperature.

For engineers reviewing the SD1A200G datasheet, SD1A200G pinout, SD1A200G application, or SD1A200G equivalent, key selection criteria include precise VBO tolerance, di/dt capability of 80 A/μs, thermal resistance of 15°C/W, RoHS-compliant DO-15 packaging, and suitability for repetitive pulse ignition circuits with minimal footprint.

Technical Context

The SD1A200G operates as a two-terminal, voltage-triggered switching device without gate control. It remains in high-impedance blocking state until applied voltage exceeds its temperature-dependent VBO (190–210 V), then latches into low-impedance conduction until current falls below IH (≤60 mA).

Its DO-15 package supports lead-free soldering at 260°C (10 s), with thermal resistance junction-to-case of 15°C/W and maximum junction temperature of +125°C - enabling reliable operation in compact, thermally constrained igniter assemblies.

Key Specifications

Pinout & Package

Package: JEDEC DO-15 molded plastic case with lead-free plating, RoHS 2011/65/EU compliant. Dimensions: A = 25.4 mm (max), B = 0.71–0.86 mm (lead diameter), C = 2.60–3.60 mm (body width), D = 5.80–7.60 mm (body length).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage-triggered thyristor applications.

Compared with STL1A200G, SD1A200G offers broader VBO tolerance for robustness against line voltage drift; compared with BT169G, it eliminates gate drive design overhead at the cost of fixed trigger timing - making SD1A200G optimal for cost-sensitive, line-synchronous gas ignition.

Availability

SD1A200G is available at Aetrix Electronics and suitable for gas igniter systems, portable propane torch controls, and commercial food warmer ignition modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for SD1A200G 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, with deep expertise in thyristors and discrete power semiconductors.

The SD1A200G belongs to Littelfuse's SIDAC family, engineered specifically for contactless, self-triggering ignition in gas-fired appliances where reliability, compactness, and line-voltage synchronization are critical.

FAQ

What is the maximum allowable junction temperature for continuous operation?

The SD1A200G has a rated operating junction temperature range of –40°C to +125°C. For continuous RMS conduction at 1 A, case temperature must be maintained at or below 80°C per the IT(RMS) derating curve. Exceeding 125°C risks irreversible degradation of the silicon structure and increased leakage current.

Can SD1A200G be used in AC or DC circuits?

SD1A200G is unidirectional and optimized for AC line-synchronized applications like gas igniters. In DC circuits, it triggers once and remains latched until current drops below IH - making it unsuitable for DC unless paired with active current interruption. Its VDRM rating applies only to repetitive AC waveforms (50–60 Hz).

Is the DO-15 package compatible with automated through-hole assembly?

Yes - the DO-15 package meets JEDEC standards for axial-lead components and is compatible with standard wave soldering and selective soldering processes. Lead spacing (B dimension: 0.71–0.86 mm) and body dimensions support pick-and-place accuracy and hole clearance in IPC-7351-compliant footprints.

How does temperature affect breakover voltage performance?

VBO decreases linearly with rising junction temperature: typical drift is –0.1%/°C relative to 25°C value. At +125°C, VBO is ~92% of its 25°C value (e.g., 190 V → ~175 V). This is documented in Fig.3 of the datasheet and must be accounted for in high-ambient designs.