Low BOM Cost AC Solid State Relay with MOSFETs Reference Design


Design files


The low BOM cost ac solid state relay with MOSFETs reference design is a single relay replacement that enables efficient power management for a low-power alternative to standard electromechanical relays in thermostat applications. This SSR reference design is the base model of the self-powered solid state relay providing a low BOM cost solution for low cost thermostats.

  • No clicking sound
  • Low cost BOM
  • Self-powered
  • Zero power from the thermostat battery
  • Inherent snubber circuit reducing voltage spike created by inductive loads
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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.

TIDUC87A.PDF (1727 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

TIDRNO3.ZIP (36283 K)

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

TIDCCN7.ZIP (1062 K)

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.

Shunt voltage references

ATL4312.5-V low-IQ adjustable precision shunt regulator

Data sheet: PDF | HTML

LP339Quad low-power commercial grade standard comparator

Data sheet: PDF
D-type flip-flops

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

Data sheet: PDF | HTML

CSD18541F560-V, N channel NexFET™ power MOSFET, single LGA 1.5 mm x 0.8mm, 65 mOhm, gate ESD protection

Data sheet: PDF | HTML

Technical documentation

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Type Title Date
* Design guide Low-Cost AC Solid-State Relay With MOSFETs Reference Design (Rev. A) Mar. 06, 2017
More literature How to power your thermostat using solid state relays Sep. 29, 2016
More literature A modern approach to solid-state relay design Sep. 29, 2016
More literature Click! Clack! What's the setback in your thermostat? Sep. 29, 2016

Related design resources

Reference designs

TIDA-00377 Self-Powered AC Solid State Relay with MOSFETs Reference Design TIDA-00751 Solid State Relay 24V AC Switch with Galvanic Isolation Reference Design TIDA-01065 Isolated Self-Powered AC Solid State Relay with MOSFETs Reference Design

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