Thyristors - DIACs, SIDACs

Part Number	Description / PDF	Quantity
K3601GRP Wickmann / Littelfuse	SIDAC 340-380V 1A DO15	0
K1050GURP Wickmann / Littelfuse	SIDAC 95-110V 1A UNI DO-15	0
SMT10002T3	THYRISTOR SURGE PROTECTION DEVIC	262500
K0820S1URP Wickmann / Littelfuse	SIDAC 75-90V 1A UNI DO-214AC	0
MKP1V240RLG Wickmann / Littelfuse	SIDAC 220-250V 900MA AXIAL	0
NTE6415 NTE Electronics, Inc.	D-SYDAC 45-60V	358
K2400EH70AP Wickmann / Littelfuse	SIDAC 220-250V 1A TO92	0
MKP3V120G	SIDAC, 130V MAX	1692
K2501GRP Wickmann / Littelfuse	SIDAC 240-280V 1A DO15	0
K1200E70AP Wickmann / Littelfuse	SIDAC 110-125V 1A TO92	0
K2000S1URP Wickmann / Littelfuse	SIDAC 190-210V 1A UNI DO-214AC	0
K1500E70AP Wickmann / Littelfuse	SIDAC 140-170V 1A TO92	0
K2200E70 Wickmann / Littelfuse	SIDAC 205-230V 1A TO92	1712
BR100-03LLD Diotec Semiconductor	DIAC DO-213AA 28V 36V	0
K2002G Wickmann / Littelfuse	SIDAC 190-215V 1A DO15	0
K2200EH70AP Wickmann / Littelfuse	SIDAC 205-230V 1A TO92	0
K2500SHRP Wickmann / Littelfuse	SIDAC 240-280V 1A DO214	0
K2201G Wickmann / Littelfuse	SIDAC 200-230V 1A DO15	0
SMDB3 STMicroelectronics	DIAC 28-36V 1A SOT23-3	3308
K3002G Wickmann / Littelfuse	SIDAC 270-330V 1A DO15	597

Thyristors - DIACs, SIDACs

1. Overview

DIACs (Diodes for Alternating Current) and SIDACs (Silicon Diodes for Alternating Current) are bidirectional trigger devices used primarily to control thyristor-based circuits. These three-layer semiconductor devices exhibit negative resistance characteristics and are critical in AC power control systems. They enable precise switching of high-voltage AC loads through their unique breakover voltage behavior, making them essential in lighting, motor control, and industrial automation applications.

2. Main Types and Functional Classification

Type	Functionality	Application Examples
DIAC	Low-power bidirectional trigger diode with symmetrical breakover voltage	TRIAC gate triggering in dimmer switches
SIDAC	Higher current/voltage capability with precise voltage clamping	Industrial motor speed controllers
Programmable DIAC	Voltage-adjustable triggering through external resistors	Customizable power control systems

3. Structure and Composition

DIACs/SIDACs typically consist of a four-layer (PNPN) silicon structure with two main terminals (A1/A2). The symmetrical doping profile creates a negative resistance region during reverse bias. Advanced devices incorporate:

Epitaxial silicon layers for precise voltage control
Passivation layers for voltage stability
Metallization patterns for thermal management
Plastic/ceramic packaging for environmental protection

4. Key Technical Specifications

Parameter	Description	Importance
Breakover Voltage (VBO)	Voltage threshold for conduction (typically 20-32V)	Determines triggering point
Trigger Current (IT)	Minimum current to sustain conduction	Impacts load compatibility
Holding Current (IH)	Current level to maintain on-state	Affects circuit stability
Peak Current (IPT)	Maximum transient current capability	Overload protection
dv/dt	Voltage change rate immunity	Prevents false triggering

5. Application Areas

Key industries and equipment:

Lighting: Smart dimming systems, LED drivers
Industrial: Conveyor belt controllers, heating systems
Consumer: Washing machine motor controls
Power Electronics: AC voltage regulators

Example: DIACs in phase-control dimmers trigger TRIACs at specific AC cycle points to adjust light intensity.

6. Leading Manufacturers and Products

Manufacturer	Product Series	Key Features
STMicroelectronics	DB3	Standard DIAC with 32V VBO
ON Semiconductor	SIDAC103	100V, 3A industrial SIDAC
Vishay	TECC94	High surge current capability

7. Selection Guidelines

Key considerations:

Match VBO to TRIAC gate requirements
Verify current ratings with load characteristics
Choose packaging based on thermal needs
Consider dv/dt ratings for noisy environments
Evaluate temperature stability for industrial applications

8. Industry Trends

Emerging developments:

Integration with wide-bandgap semiconductors (SiC/GaN)
Miniaturization for PCB space optimization
Improved dv/dt immunity for EV charging systems
Smart grid compatibility with IoT-enabled controllers

Market growth driven by energy-efficient lighting and industrial automation demands.