TUV-assessed digital input reference design for IEC 61508 (SIL-2)


Design files


This 8-channel, group-isolated, digital input module reference design, focuses on applications with the need for industrial functional safety. This design has diagnostics implemented to help detect both permanent and transient random hardware faults. The concept of this input module has been assessed by TUEV SUED (TÜV SÜD) and helps designers meet system compliances of IEC61508-2:2010 (SIL2) and EN13849-1:2015 (Cat2 PLd). Additionally, this design has a hardware fault tolerance (HFT) of 0 (1oo1D architecture) and digital inputs designed to comply with IEC61131-2 (type 1) recommendations.

  • Group-isolated 8-channel digital input compliant to IEC61131-2 (type 1)
  • Concept meets requirements of IEC61508-2:2010 (SIL2) and EN13849-1:2015 (Cat2 PLd) (assessed by TÜV SÜD)
  • Diagnostics and monitoring features
  • Miswiring protection (reverse polarity, digital input short/open/cross-wire)
  • Small footprint
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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.

TIDUEN7.PDF (1715 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


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

TIDRZU3.PDF (2566 K)

PCB layer plot file used for generating PCB design layout

TIDRZU4.ZIP (2441 K)

PCB layer plot file used for generating PCB design layout


Includes TI products in the design and potential alternatives.

AND gates

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Arm Cortex-R MCUs

RM41L23216/32 Bit RISC Flash MCU, Arm Cortex-R4F

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Buck converters (integrated switch)

LM51663V-65V Input, 500mA Synchronous Buck Converter With Ultra-Low Iq

Data sheet: PDF | HTML
Buck converters (integrated switch)

LMR360064.2-V to 60-V, 0.6-A ultra-small synchronous step-down converter

Data sheet: PDF | HTML
Buck converters (integrated switch)

TPS622302 MHz Ultra Small Step Down Converter with DCS-Control in 1x1.5 SON Package

Data sheet: PDF | HTML
Digital isolators

ISO7741Robust EMC, quad-channel, 3/1, reinforced digital isolator

Data sheet: PDF | HTML
General-purpose op amps

TLV9001One-channel, 1-MHz rail-to-rail input and output 1.8-V to 5.5-V operational amplifier

Data sheet: PDF | HTML
Load switches

TPS229175.5-V, 2-A, 80-mΩ , 10-nA leakage load switch adj. rise time and adj output discharge

Data sheet: PDF | HTML
N-channel MOSFETs

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

Data sheet: PDF | HTML
NAND gates

SN74LVC2G1322-ch, 2-input, 1.65-V to 5.5-V NAND gates with Schmitt-Trigger inputs

Data sheet: PDF
Noninverting buffers & drivers

SN74LVC1G125Single 1.65-V to 5.5-V buffer with 3-state outputs

Data sheet: PDF | HTML
Series voltage references

REF30303-V, 50-ppm/°C, 50-µA in 3-pin SOT-23 package series (bandgap) voltage reference

Data sheet: PDF | HTML
Shift registers

SN74AHC5948-Bit Shift Registers With Output Registers

Data sheet: PDF | HTML
Shunt voltage references

TL431LIAdjustable precision shunt regulator with optimized reference current (pin layout: KRA)

Data sheet: PDF | HTML
Supervisor & reset ICs

TPS3700High-voltage (18-V) window voltage detector for overvoltage and undervoltage monitoring

Data sheet: PDF | HTML
Supervisor & reset ICs

TPS3852High-accuracy voltage supervisor with programmable window watchdog timer

Data sheet: PDF | HTML
TVS diodes

TVS05005V flat-clamp surge protection device

Data sheet: PDF | HTML
Temperature switches

TMP302Pin-Selectable Trip Point 1.4V-Capable Family of Temperature Switches

Data sheet: PDF | HTML
eFuses & hot swap controllers

TPS26624.5-V to 60-V, 478mΩ, 0.025-0.88A eFuse with integrated input and output reverse polarity protection

Data sheet: PDF | HTML

Start development

Design tools & simulation

Simulation model

TIDA-010049 Simulation — TIDM060.ZIP (38 K)

Technical documentation

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Type Title Date
* User guide TIDA-010049 TUEV Concept Report Jun. 07, 2019
* Design guide TUV-Assessed Digital Input Reference Design for IEC 61508 (SIL-2) Jun. 05, 2019

Related design resources

Hardware development

TMDSEMU200-U XDS200 USB Debug Probe

Software development

CCSTUDIO Code Composer Studio™ integrated development environment (IDE) HALCOGEN Hardware Abstraction Layer Code Generator for Hercules MCUs

Reference designs

TIDA-01552 8 Channel, 2-A High-Side Driver Reference Design for Digital Output Modules

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