Thyristors - DIACs, SIDACs

Image	Part Number	Description / PDF	Quantity	Rfq
	K2000F1 Wickmann / Littelfuse	SIDAC 190-215V 1A TO92	0
	HT5761 Wickmann / Littelfuse	DIAC 28-36V 2A DO35	0
	K1400S Wickmann / Littelfuse	SIDAC 130-146V 1A DO214	0
	LIC01-195H STMicroelectronics	DIAC 195-230V 1.2A IPAK	0
	HT60RP Wickmann / Littelfuse	DIAC 56-70V 1.5A DO35	0
	ST36ARP Wickmann / Littelfuse	DIAC 32-40V 2A DO214	0
	HT5761ARP Wickmann / Littelfuse	DIAC 30-34V 2A DO35	0
	MA2B00100F Panasonic	DIAC 28-36V 2A DO35	0
	K0900S Wickmann / Littelfuse	SIDAC 79-97V 1A DO214	0
	ST32 Wickmann / Littelfuse	DIAC 27-37V 2A DO214	0
	K3000F1 Wickmann / Littelfuse	SIDAC 270-330V 1A TO202	0
	HT40RP Wickmann / Littelfuse	DIAC 35-45V 2A DO35	0
	K2000F23 Wickmann / Littelfuse	SIDAC 190-215V 1A TO202	0
	HT5761RP Wickmann / Littelfuse	DIAC 28-36V 2A DO35	0
	ST34BRP Wickmann / Littelfuse	DIAC 32-36V 2A DO214	0
	HT35RP Wickmann / Littelfuse	DIAC 30-40V 2A DO35	0
	MKP1V160 Sanyo Semiconductor/ON Semiconductor	SIDAC 150-170V 900MA AXIAL	0
	BR100/03,113 NXP Semiconductors	DIAC 28-36V 2A ALF2	0
	ST40 Wickmann / Littelfuse	DIAC 35-45V 2A DO214	0
	K1300S Wickmann / Littelfuse	SIDAC 120-138V 1A DO214	0

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.