# Universal I/O Controller ## Description Single-channel Universal Input schematic with LM76202 field protection, AD7708 ADC measurement core, CD4066 mode switching, HC595 control mapping, and comparator-backed digital input support for DI, analog, 0-10 V, 0-20 mA, resistance, RTD, and thermistor modes. ## Project Details - **Owner:** michelelmurr - **Created:** 5/6/2026 - **Last Updated:** 5/12/2026 - **Visibility:** Public ## Key Components ### D1 — [SM6T18A](https://www.flux.ai/jecstronic/sm6t18a~t3f.md) - Role: Input Protection - Manufacturer Part Number: SM6T18A - Datasheet URL: https://www.mouser.com/datasheet/2/389/sm6t100a-1916590.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Diode - Manufacturer Name: STMicroelectronics - Role Details: TVS clamp on universal input field terminal **Pins:** - A [pin 2] - K [pin 1] ### H1 — [M3*12+3](https://www.flux.ai/lcsc/m312plus3~uy8l.md) - Manufacturer Part Number: M3*12+3 - Role Details: Corner M3 mounting point for 100x160mm Universal I/O Controller PCB - Role: Mounting Hole - Part Type: Hardware Fasteners (Screws) - LCSC Part Number: C110574 - Package or Case Code: TH_BD4.7-D3.0 - Manufacturer Name: 国产 **Pins:** - 1 [pin 1] ### H2 — [M3*12+3](https://www.flux.ai/lcsc/m312plus3~uy8l.md) - Package or Case Code: TH_BD4.7-D3.0 - Manufacturer Name: 国产 - LCSC Part Number: C110574 - Part Type: Hardware Fasteners (Screws) - Role Details: Corner M3 mounting point for 100x160mm Universal I/O Controller PCB - Manufacturer Part Number: M3*12+3 - Role: Mounting Hole **Pins:** - 1 [pin 1] ### H3 — [M3*12+3](https://www.flux.ai/lcsc/m312plus3~uy8l.md) - Role: Mounting Hole - Manufacturer Part Number: M3*12+3 - Package or Case Code: TH_BD4.7-D3.0 - Manufacturer Name: 国产 - Role Details: Corner M3 mounting point for 100x160mm Universal I/O Controller PCB - LCSC Part Number: C110574 - Part Type: Hardware Fasteners (Screws) **Pins:** - 1 [pin 1] ### H4 — [M3*12+3](https://www.flux.ai/lcsc/m312plus3~uy8l.md) - Role: Mounting Hole - Manufacturer Part Number: M3*12+3 - Package or Case Code: TH_BD4.7-D3.0 - Manufacturer Name: 国产 - Role Details: Corner M3 mounting point for 100x160mm Universal I/O Controller PCB - Part Type: Hardware Fasteners (Screws) - LCSC Part Number: C110574 **Pins:** - 1 [pin 1] ### IC1 — [LM4040AIZ-2.5/NOPB](https://www.flux.ai/adrian95/lm4040aiz-2p5nopb~xoa.md) - Role: ADC Reference - Manufacturer Part Number: LM4040AIZ-2.5/NOPB - Part Type: Integrated Circuit - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: 2.5V reference for AD7708 REFIN1+; REFIN1- returns to AGND - Datasheet URL: https://www.ti.com/lit/ds/symlink/lm4040-n.pdf - Manufacturer Name: Texas Instruments Inc. **Pins:** - ANODE [pin 1] - CATHODE [pin 2] - NC [pin 3] ### J1 — [KF128-5.08-2P-AA](https://www.flux.ai/lcsc/kf128-5p08-2p-aa~0pbi.md) - Product Info Url: https://lcsc.com/product-detail/New-Quadratic-Unclassified-Data_Cixi-Kefa-Elec-KF128-5-08-2P_C474952.html - Current Rating: 24A - Manufacturer Name: KEFA(科发) - Connector Pitch: 5.08mm - LCSC Part Number: C474952 - Connector Gender: Female - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2408211511_Cixi-Kefa-Elec-KF128-5-08-2P-AA_C474952.pdf - Package or Case Code: CONN-TH_P5.08_KF128-5.08-2P - Connector Rows: 1 - JLCPCB Part Class: Extended Part - Manufacturer Part Number: KF128-5.08-2P-AA - Connector Type: Screw terminal - Part Type: Screw terminal - Operating Temperature: -40℃~+105℃ - Connector Positions: 2 **Pins:** - 1 [pin 1] - 2 [pin 2] ### J10 — [TSW-116-07-G-S](https://www.flux.ai/adrian95/tsw-116-07-g-s~78t.md) - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: Samtec - Part Type: Connector - Manufacturer Part Number: TSW-116-07-G-S - Datasheet URL: https://suddendocs.samtec.com/catalog_english/tsw_th.pdf - Role Details: Expanded 1x16 software interface: power, SPI, HC595 latch/control, comparator outputs, UO analog command inputs - Role: Control Header **Pins:** - 01 [pin 01] - 02 [pin 02] - 03 [pin 03] - 04 [pin 04] - 05 [pin 05] - 06 [pin 06] - 07 [pin 07] - 08 [pin 08] - 09 [pin 09] - 10 [pin 10] - 11 [pin 11] - 12 [pin 12] - 13 [pin 13] - 14 [pin 14] - 15 [pin 15] - 16 [pin 16] ### J9 — [Pin Header 01x06 2.54mm PROGRAMMING CONNECTOR](https://www.flux.ai/zalak201285/pin-header-01x06-2p54mm-programming-connector~ji.md) - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - JTCK [pin 2] - JTDI [pin 1] - JTDO [pin 3] - JTMS [pin 4] - NJTRST [pin 5] - RESET [pin 6] ### U1 — [LM76202QPWPRQ1](https://www.flux.ai/lcsc/lm76202qpwprq1~cty2.md) - Implementation Details: LM76202-Q1 24V field-input protection: UVLO divider R31=143k/R32=10k (~18V rising), OVP divider R33=274k/R34=10k (~33.8V cutoff), ILIM R35=5.36kΩ (~2.23A), IMON R36=20kΩ, dVdT C26=12nF, input bypass C27=1µF, output bulk C22=47µF. - Role Details: LM76202 protects/supervises FIELD_24V input for universal I/O field circuits - Manufacturer Name: Texas Instruments - Manufacturer Part Number: LM76202QPWPRQ1 - Datasheet URL: https://www.ti.com/lit/ds/symlink/lm76202-q1.pdf - LCSC Part Number: C1849484 - Role: Power Protection - JLCPCB Part Class: Extended Part - Package or Case Code: HTSSOP-16_L5.0-W4.4-P0.65-LS6.4-BL-EP - Part Type: Monitors & Reset Circuits **Pins:** - ~{FLT} [pin 14] - ~{SHDN} [pin 7] - dVdT [pin 12] - EP [pin 17] - GND [pin 9] - ILIM [pin 11] - IMON [pin 10] - IN [pin 1] - IN [pin 2] - MODE [pin 6] - NC [pin 13] - NC [pin 4] - OUT [pin 16] - OUT [pin 15] - OVP [pin 5] - RTN [pin 8] - UVLO [pin 3] ### U10 — [AP2204K-3.3TRG1](https://www.flux.ai/lcsc/ap2204k-3p3trg1~bqht.md) - LCSC Part Number: C112032 - Manufacturer Part Number: AP2204K-3.3TRG1 - Manufacturer Name: DIODES(美台) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_Diodes-Incorporated-AP2204K-3-3TRG1_C112032.pdf - JLCPCB Part Class: Extended Part - Package or Case Code: SOT-23-5_L3.0-W1.7-P0.95-LS2.8-BR - Part Type: Linear Voltage Regulators (LDO) - Role Details: Generates 3V3 for AD7708 DVDD/AVDD, HC595, CD4066 controls, and logic pull-ups from 5V_IN - Product Info Url: https://lcsc.com/product-detail/Low-Dropout-Regulators-LDO_DIODES_AP2204K-3-3TRG1_AP2204K-3-3TRG1_C112032.html - Role: 3V3 Regulator **Pins:** - ADJ/NC [pin 4] - EN [pin 3] - GND [pin 2] - VIN [pin 1] - VOUT [pin 5] ### U2 — [AD7708BRUZ](https://www.flux.ai/lcsc/ad7708bruz~z71i.md) - LCSC Part Number: C651436 - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2304140030_Analog-Devices-AD7708BRUZ_C651436.pdf - Package or Case Code: TSSOP-28_L9.7-W4.4-P0.65-LS6.4-BL - JLCPCB Part Class: Extended Part - Role Details: Digitizes four scaled universal-input channels and resistance sensor measurements - Manufacturer Name: ADI(亚德诺) - Part Type: Analog To Digital Converters (ADCs) - Product Info Url: https://lcsc.com/product-detail/Analog-To-Digital-Converters-ADCs_Analog-Devices_AD7708BRUZ_Analog-Devices-ADI-LINEAR-AD7708BRUZ_C651436.html - Manufacturer Part Number: AD7708BRUZ - Role: ADC **Pins:** - ~{CS} [pin 21] - ~{RDY} [pin 22] - ~{RESET} [pin 19] - AGND [pin 4] - AGND [pin 17] - AIN1 [pin 7] - AIN2 [pin 8] - AIN3 [pin 9] - AIN4 [pin 10] - AIN5 [pin 11] - AIN6 [pin 15] - AIN7 [pin 1] - AIN8 [pin 2] - AINCOM [pin 12] - AVDD [pin 3] - DGND [pin 25] - DIN [pin 24] - DOUT [pin 23] - DVDD [pin 26] - P1 [pin 18] - P2 [pin 16] - REFIN1(-) [pin 5] - REFIN1(+) [pin 6] - REFIN2(-)/AIN10 [pin 14] - REFIN2(+)/AIN9 [pin 13] - SCLK [pin 20] - XTAL1 [pin 28] - XTAL2 [pin 27] ### U3 — [LM2903DR2G](https://www.flux.ai/adrian95/lm2903dr2g~3fw.md) - Role Details: LM290-family comparator converts universal input nodes to digital threshold signals - Part Type: Integrated Circuit - Manufacturer Part Number: LM2903DR2G - Role: Comparator - Datasheet URL: https://www.onsemi.com/pdf/datasheet/lm393-d.pdf - Manufacturer Name: onsemi - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - GND [pin 4] - INPUTS_A_1 [pin 2] - INPUTS_A_2 [pin 3] - INPUTS_B_1 [pin 5] - INPUTS_B_2 [pin 6] - OUTPUT_A [pin 1] - OUTPUT_B [pin 7] - VCC [pin 8] ### U4 — [74HC595PW,118](https://www.flux.ai/vasy_skral/74hc595pwc118~lf.md) - Part Type: Integrated Circuit - Role Details: HC595 expands software outputs for mode-select switches and digital output control - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 74HC595PW,118 - Manufacturer Name: Nexperia USA Inc. - Datasheet URL: https://assets.nexperia.com/documents/data-sheet/74HC_HCT595.pdf - Role: I/O Expansion **Pins:** - ~OE [pin 13] - ~SRCLR [pin 10] - GND [pin 8] - QA [pin 15] - QB [pin 1] - QC [pin 2] - QD [pin 3] - QE [pin 4] - QF [pin 5] - QG [pin 6] - QH [pin 7] - QH' [pin 9] - RCLK [pin 12] - SER [pin 14] - SRCLK [pin 11] - VCC [pin 16] ### U6 — [CD4066BPWR](https://www.flux.ai/vasy_skral/cd4066bpwr~x5p.md) - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Integrated Circuit - Role: Mode Switch - Role Details: Routes UI1 among voltage, current shunt, resistance/RTD/thermistor excitation, and ADC filter paths - Manufacturer Part Number: CD4066BPWR - Manufacturer Name: Texas Instruments - Datasheet URL: https://www.ti.com/lit/ds/symlink/cd4066b.pdf **Pins:** - CONTROL_A [pin 13] - CONTROL_B [pin 5] - CONTROL_C [pin 6] - CONTROL_D [pin 12] - SIG_A_IN/OUT [pin 1] - SIG_A_OUT/IN [pin 2] - SIG_B_IN/OUT [pin 4] - SIG_B_OUT/IN [pin 3] - SIG_C_IN/OUT [pin 8] - SIG_C_OUT/IN [pin 9] - SIG_D_IN/OUT [pin 11] - SIG_D_OUT/IN [pin 10] - VDD [pin 14] - VSS [pin 7] ### Y1 — [ABS07-32.768KHZ-T](https://www.flux.ai/adrian95/abs07-32768khz-t~822.md) - Datasheet URL: https://abracon.com/Resonators/ABS07.pdf - Part Type: Oscillator - Manufacturer Name: Abracon LLC - License: https://creativecommons.org/licenses/by/4.0/ - Role: ADC Clock - Manufacturer Part Number: ABS07-32.768KHZ-T - Role Details: 32.768kHz crystal between AD7708 XTAL1 and XTAL2 **Pins:** - P1 [pin 1] - P2 [pin 2] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/michelelmurr/universal-io-controller~30](https://www.flux.ai/michelelmurr/universal-io-controller~30).* --- *Generated from [https://www.flux.ai/michelelmurr/universal-io-controller~30](https://www.flux.ai/michelelmurr/universal-io-controller~30)*