# Portable Potentiostat ## Description Portable potentiostat PCB with low-noise analog front end, dual 3.3 V rails, and 4-layer mixed-signal layout for heavy-metal voltammetry. ## Project Details - **Owner:** alfonso-ontiveros - **Created:** 4/14/2026 - **Last Updated:** 4/17/2026 - **Visibility:** Public ## Key Components ### IC1 — [LT6657AHMS8-2.5](https://www.flux.ai/vasyl/lt6657ahms8-25~eds.md) - Role Details: Low-drift 2.5 V reference feeding the potentiostat reference node and ADC reference path - Package: MSOP-8 - Role: Voltage Reference - Manufacturer Part Number: LT6657AHMS8-2.5 - Part Type: Integrated Circuit - Datasheet URL: https://www.analog.com/media/en/technical-documentation/data-sheets/6657fd.pdf - Voltage: 2.5V - Implementation Details: Pins 1, 5, 7, and 8 are DNC. Datasheet states 'CONNECTED INTERNALLY' and 'DO NOT CONNECT EXTERNAL CIRCUITRY TO THESE PINS.' Leave all DNC pins floating with no copper or net attachment. - Manufacturer Name: Analog Devices Inc. **Pins:** - ~SHDN [pin 3] - DNC [pin 5] - DNC [pin 1] - DNC [pin 8] - DNC [pin 7] - GND [pin 4] - OUT [pin 6] - Vin [pin 2] ### J1 — [282837-3](https://www.flux.ai/adrian95/282837-3~5mc.md) - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: TE Connectivity AMP Connectors - Part Type: Connector - Role Details: Three-position hand-solderable field connector for WE, RE, and CE electrode leads - Manufacturer Part Number: 282837-3 - Datasheet URL: https://www.te.com/usa-en/product-282837-3.datasheet.pdf - Role: Electrode Connector - Package: TerminalBlock_5.08_3pos **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 2] - Pin_3 [pin 3] ### J3 — [TSW-105-07-G-S](https://www.flux.ai/adrian95/tsw-105-07-g-s~klw.md) - Manufacturer Part Number: TSW-105-07-G-S - Manufacturer Name: Samtec - Role: SWD Header - Datasheet URL: https://suddendocs.samtec.com/catalog_english/tsw_th.pdf - Role Details: 1x5 2.54mm programming header carrying GND, VTref, SWCLK, SWDIO, and RESET - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector **Pins:** - 01 [pin 01] - 02 [pin 02] - 03 [pin 03] - 04 [pin 04] - 05 [pin 05] ### J4 — [61300411121](https://www.flux.ai/adrian95/61300411121~pw9.md) - Manufacturer Name: Wurth Elektronik - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 61300411121 - Implementation Details: Header pin 1 is the RTIA common node tied to C2 of U1. Install a shunt from pin 1 to pin 2 for 100kΩ, pin 1 to pin 3 for 1MΩ, or pin 1 to pin 4 for 10MΩ. Only one shunt should be installed at a time. - Role Details: Common-plus-selection header that lets a shunt choose one of several RTIA resistors during bring-up - Package or Case Code: HDRV4W95P0X254_1X4_1016X254X854P - Datasheet URL: https://www.we-online.com/components/products/datasheet/61300411121.pdf - Role: RTIA Select Header - Part Type: Connector **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] ### SW1 — [Slide Switch SW_SPDT](https://www.flux.ai/404src/slide-switch-swspdt~nq.md) - Datasheet URL: https://www.taydaelectronics.com/datasheets/A-5111.pdf - Role: Power Switch - Purchase Url: https://www.taydaelectronics.com/slide-switch-1p2t-through-hole-0-5a-50vdc.html - Role Details: Master battery on/off switch before the local regulators - Manufacturer Name: Wealth Metal - Implementation Details: SS12F44G5 is a 1P2T non-shorting switch with center terminal as common. For SPST battery on/off use, the unused throw is intentionally left unconnected. - Manufacturer Part Number: SS12F44G5 **Pins:** - A [pin 1] - B [pin 2] - C [pin 3] ### SW2 — [B3F-4000](https://www.flux.ai/adrian95/b3f-4000~zx9.md) - Manufacturer Name: Omron Electronics Inc-EMC Div - Role Details: Manual reset pushbutton for field recovery and firmware loading - Role: Reset Switch - Part Type: Switch - Datasheet URL: https://omronfs.omron.com/en_US/ecb/products/pdf/en-b3f.pdf - Manufacturer Part Number: B3F-4000 - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] ### U1 — [LMP91000SDE/NOPB](https://www.flux.ai/adrian95/lmp91000sdenopb~d5k.md) - Operating Voltage: 2.7V to 5.25V - Manufacturer Name: Texas Instruments - Package: WSON-14 - Role Details: Controls WE/RE/CE electrochemical cell and outputs analog measurement signal referenced to external VREF - Manufacturer Part Number: LMP91000SDE/NOPB - Role: Potentiostat AFE - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.ti.com/lit/ds/symlink/lmp91000.pdf - Part Type: Integrated Circuit **Pins:** - AGND [pin 7] - C1 [pin 10] - C2 [pin 9] - CE [pin 14] - DGND [pin 1] - EP [pin 15] - MENB [pin 2] - NC [pin 5] - RE [pin 13] - SCL [pin 3] - SDA [pin 4] - VDD [pin 6] - VOUT [pin 8] - VREF [pin 11] - WE [pin 12] ### U2 — [ADS1120-PW](https://www.flux.ai/kicad-part-library/ads1120-pw~p4h.md) - Manufacturer Part Number: ADS1120-PW - Implementation Details: Unused ADS1120 pins handled per datasheet: CLK tied to DGND to force internal oscillator; AIN2 tied to AVDD/3V3_A as a defined unused analog input; DRDY held high with a weak pull-up because it is not used; AIN3/REFN1 intentionally left floating because the datasheet calls it out as an exception that should remain unconnected when unused. - Package: TSSOP-16 - Package or Case Code: TSSOP-16_4.4x5mm_P0.65mm - Role Details: External 16-bit ADC used for first-pass low-noise digitization because original EVM ADC was not available in library - Manufacturer Name: Texas Instruments Inc. - Datasheet URL: http://www.ti.com/lit/ds/symlink/ads1120.pdf - Role: ADC **Pins:** - ~{CS} [pin 2] - ~{DRDY} [pin 14] - AIN0/REFP1 [pin 11] - AIN1 [pin 10] - AIN2 [pin 7] - AIN3/REFN1 [pin 6] - AVDD [pin 12] - AVSS [pin 5] - CLK [pin 3] - DGND [pin 4] - DIN [pin 16] - DOUT/~{DRDY} [pin 15] - DVDD [pin 13] - REFN0 [pin 8] - REFP0 [pin 9] - SCLK [pin 1] ### U3 — [TPS79301-EP](https://www.flux.ai/kicad-part-library/tps79301-ep~q3p.md) - Max Output Voltage: 3.3V - Manufacturer Part Number: TPS79301-EP - Package or Case Code: SOT-23-6 - Min Output Voltage: 3.3V - Role: Analog LDO - Datasheet URL: http://www.ti.com/lit/ds/symlink/tps79333-ep.pdf - Role Details: Generates low-noise 3.3 V analog rail for LMP91000, reference, and ADC analog supply - Package: SOT-23-6 - Manufacturer Name: Texas Instruments Inc. **Pins:** - BP [pin 4] - EN [pin 3] - FB [pin 5] - GND [pin 2] - IN [pin 1] - OUT [pin 6] ### U4 — [TPS79301-EP](https://www.flux.ai/kicad-part-library/tps79301-ep~q3p.md) - Min Output Voltage: 3.3V - Package or Case Code: SOT-23-6 - Package: SOT-23-6 - Manufacturer Part Number: TPS79301-EP - Role Details: Generates isolated 3.3 V digital rail for MCU and digital side of ADC - Role: Digital LDO - Manufacturer Name: Texas Instruments Inc. - Datasheet URL: http://www.ti.com/lit/ds/symlink/tps79333-ep.pdf - Max Output Voltage: 3.3V **Pins:** - BP [pin 4] - EN [pin 3] - FB [pin 5] - GND [pin 2] - IN [pin 1] - OUT [pin 6] ### U5 — [ATSAMD10C13A-SS](https://www.flux.ai/vasyl/atsamd10c13a-ss~vy2.md) - Datasheet URL: http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-42242-SAM-D10_Datasheet.pdf - Part Type: Microcontroller - Role Details: Controls the LMP91000 over I2C and acquires data from the ADC over SPI for portable instrument firmware - Implementation Details: Unused MCU pins PA02, PA08/XIN, and PA09/XOUT are hardware-biased with weak 100 kOhm pulldowns and should also be configured in firmware to a defined state. SWD and reset remain available for programming/debug. - Manufacturer Name: Microchip - Role: Microcontroller - Package: SOIC-14 - Manufacturer Part Number: ATSAMD10C13A-SS **Pins:** - GND [pin 11] - PA02 [pin 13] - PA04 [pin 14] - PA05 [pin 1] - PA08/XIN [pin 2] - PA09/XOUT [pin 3] - PA14 [pin 4] - PA15 [pin 5] - PA24 [pin 9] - PA25 [pin 10] - PA28/~RST [pin 6] - PA30/SWCLK [pin 7] - PA31/SWDIO [pin 8] - VDD [pin 12] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/alfonso-ontiveros/portable-potentiostat~qk](https://www.flux.ai/alfonso-ontiveros/portable-potentiostat~qk).* --- *Generated from [https://www.flux.ai/alfonso-ontiveros/portable-potentiostat~qk](https://www.flux.ai/alfonso-ontiveros/portable-potentiostat~qk)*