Solid State Relay 24V AC Switch with Galvanic Isolation Reference Design


Design files


The solid state relay 24V AC Switch reference design is a single relay replacement that enables efficient power management for a low power alternative to standard electromechanical relays.  The OFF-mode provides energy to the system controller and the ON mode can switch fast enough to allow backup battery charging where electromechanical relays cannot.  The internal transformer enables isolation and a voltage multiplier ensures enough current to control other relays in the rest of the system.

  • Single electromechanical relay replacement
  • Low power solid state relay with silent operation
  • No clicking noise
  • <1µs Turn-on and Turn-off switching time
  • In OFF-mode, 24-VAC line provides energy to the system
  • <200µA consumption in OFF-mode
  • Cost efficient BOM
??image.gallery.download_en_US?? View video with transcript Video

A fully assembled board has been developed for testing and performance validation only, and is not available for sale.

Design files & products

Design files

Download ready-to-use system files to speed your design process.

TIDUB92B.PDF (1313 K)

Reference design overview and verified performance test data


Detailed schematic diagram for design layout and components


Complete listing of design components, reference designators, and manufacturers/part numbers


Detailed overview of design layout for component placement


Files used for 3D models or 2D drawings of IC components


Design file that contains information on physical board layer of design PCB


PCB layer plot file used for generating PCB design layout


Includes TI products in the design and potential alternatives.

D-type flip-flops

SN74AUP1G74Low-Power Single Positive-Edge-Triggered D-Type Flip-Flop

Data sheet: PDF | HTML
Digital demultiplexers & decoders

SN74LVC1G191-of-2 Decoder/Demultiplexer

Data sheet: PDF | HTML
Inverting buffers & drivers

SN74AUP3G143-ch, 0.8-V to 3.6-V low power inverters with Schmitt-Trigger inputs

Data sheet: PDF

CSD19537Q3100-V, N channel NexFET™ power MOSFET, single SON 3 mm x 3 mm, 14.5 mOhm

Data sheet: PDF | HTML
Real-time clocks (RTCs) & timers

LMC555World’s smallest 555 timer with low power, high accuracy and a Fmax of 3MHz

Data sheet: PDF | HTML

Technical documentation

= Top documentation selected by TI
No results found. Please clear your search and try again.
View all 4
Type Title Date
* Design guide Solid-State Relay (SSR) 24-VAC Switch with Galvanic Isolation Design Guide (Rev. B) Mar. 08, 2016
Technical article How to power your thermostat using solid state relays PDF | HTML Aug. 11, 2016
Technical article A modern approach to solid-state relay design PDF | HTML Jul. 26, 2016
Technical article Click! Clack! What’s the setback in your thermostat? PDF | HTML Jun. 28, 2016

Related design resources

Reference designs

TIDA-00377 Self-Powered AC Solid State Relay with MOSFETs Reference Design TIDA-01064 Low BOM Cost AC Solid State Relay with MOSFETs Reference Design TIDA-01065 Isolated Self-Powered AC Solid State Relay with MOSFETs Reference Design

Support & training

TI E2E™ forums with technical support from TI engineers

View all forum topics

Content is provided "as is" by TI and community contributors and does not constitute TI specifications. See terms of use.

If you have questions about quality, packaging or ordering TI products, see TI support. ​​​​​​​​