Getting Started with the ProtoCentral ADS1262 32-bit ADC Breakout v4

The ProtoCentral ADS1262 breakout v4 puts Texas Instruments’ 32-bit delta-sigma ADC on a breadboard-friendly board that runs from a single supply pin. This guide takes you from an unboxed board to your first high-resolution voltage reading on an Arduino or ESP32.

Have an earlier board? v4 changed the power pins. Older boards have separate analog and digital supply pins; v4 has a single VCC pin. Check the label next to the pins: if your board has AVDD and DVDD pins, follow the original board’s Getting Started guide instead.

Introduction

The ADS1262 is a 32-bit delta-sigma ADC with a low-noise programmable gain amplifier (PGA), a 2.5 V internal reference, two sensor-excitation current sources (IDACs) and a programmable digital filter. It resolves microvolt-level signals from load cells, strain gauges, RTDs and thermocouples without external signal conditioning.

The ADS1262’s analog supply must be 4.75–5.25 V; it has no 3.3 V analog mode. The v4 board generates that rail itself:

• A TI LM2775 regulated charge pump turns your VCC into a 5.0 V analog supply. It runs at a fixed 2 MHz.
• A two-stage LC filter built from shielded inductors cleans that rail before it reaches the ADC.
• The ADS1262’s digital side runs from VCC through a ferrite, so its I/O level always matches your host. No level translator is needed.

Key Features

• 32-bit ΔΣ ADC, 2.5 SPS to 38,400 SPS
• 10 analog inputs plus AINCOM: 10 single-ended or 5 differential channels
• PGA with gains of 1 to 32, 2.5 V internal reference, two IDACs
• Single VCC pin for 3.3 V or 5 V hosts; the 5 V analog rail is made on board
• On-board pull-ups on START and RST/PWDN, so five signal wires get you to a first reading
• 6.2 V Zener clamp on the 5 V analog rail
• External clock input (CLKIN) with a selection jumper
• Four plated M2 mounting holes

What’s in the Box

Solder the 12-pin strip to the analog header if you want to plug the board into a breadboard or use jumper wires on the inputs; you can also solder sensor wires straight to the pads.

Specifications

Pinout

Host header

With START left unconnected, its pull-up keeps the ADS1262 converting continuously. The library resets the chip over SPI, so RST/PWDN can stay unconnected too.

Analog header

CLK jumper

The 3-pad CLK jumper selects the ADS1262 clock source. As shipped it ties the clock input to GND, which selects the ADS1262’s internal oscillator. Move it to the CLKIN side only if you are feeding an external clock into the CLKIN pin.

Wiring

Power VCC from your host’s logic voltage. The ADS1262’s digital pins run at VCC with no level translator in between. Use 5 V for a 5 V board such as the Arduino Uno, and 3.3 V for a 3.3 V board such as the ESP32. Driving 5 V signals into a board powered at 3.3 V can damage the ADS1262.

Arduino Uno (5 V)

These match the library’s default pins, so the examples run unchanged.

ESP32 (3.3 V)

Don’t use GPIO 6–11 on a classic ESP32: they connect to the module’s internal flash, and wiring anything to them stops the board from booting. Also avoid GPIO 16–17 on WROVER modules, which use them for PSRAM. Pass your pins to the library’s constructor:

ADS1262 adc(5, 21, 22, 4);   // CS, DRDY, START, PWDN
// in setup():
adc.begin(18, 19, 23);       // SCK, MISO, MOSI

Installing the Arduino Library

Option 1 — Library Manager (recommended)

1. In the Arduino IDE, open Tools → Manage Libraries…
2. Search for ProtoCentral ADS1262.
3. Install ProtoCentral ADS1262 32-bit precision ADC Library.

Option 2 — Manual install from GitHub

1. Download the library as a ZIP from github.com/Protocentral/ProtoCentral_ads1262 (Code → Download ZIP).
2. In the Arduino IDE, choose Sketch → Include Library → Add .ZIP Library… and select the file.

Your First Reading

Open File → Examples → ProtoCentral ADS1262 → 01-Basic-Usage. It measures the differential voltage between AIN0 and AIN1 at 100 samples per second, with a gain of 1 and the internal 2.5 V reference. The core of the setup is:

#include <ads1262.h>

ADS1262 adc(7, 6, 5, 4);   // CS, DRDY, START, PWDN — the Uno defaults

void setup() {
    Serial.begin(115200);
    if (!adc.begin()) {
        Serial.println("ADS1262 not found - check wiring and power");
        while (1) delay(1000);
    }
    adc.setDataRate(ADS1262_DR_100_SPS);
    adc.setGain(ADS1262_GAIN_1);
    adc.setReference(ADS1262_REF_INTERNAL_2_5V);
    adc.setInputMux(ADS1262_AIN0, ADS1262_AIN1);
    adc.startConversion();
}

void loop() {
    Serial.println(adc.readVoltage(), 6);
    delay(500);
}

Upload it and open the Serial Monitor at 115200 baud. With nothing connected you’ll see a small offset, typically under 1 mV. Connect a battery or a potentiometer wiper across AIN0 and AIN1 to see a real reading.

The library includes four examples:

Measuring a 0–5 V single-ended signal

For a ground-referenced signal of up to 5 V:

1. Connect the signal to an input (for example AIN0) and tie AINCOM to AVSS.
2. Measure AIN0 against AINCOM and use the 5 V analog supply as the reference.
3. Bypass the PGA. With the PGA enabled, its input range doesn’t reach the supply rails, so readings near 0 V and 5 V clip.

adc.setReference(ADS1262_REF_INTERNAL_AVDD_AVSS);
adc.setInputMux(ADS1262_AIN0, ADS1262_AINCOM);
// MODE2: bit 7 = PGA bypass, bits 6:4 = gain (000 = 1), bits 3:0 = data rate.
// Write it last: setGain() and setDataRate() also write MODE2.
adc.writeRegister(ADS1262_REG_MODE2, 0x80 | ADS1262_DR_100_SPS);

The 5 V rail is the reference here, so its accuracy limits the reading. For the best accuracy on small signals, keep the PGA enabled and use the 2.5 V internal reference.

Troubleshooting

Resources

• Arduino library on GitHub
• v4 schematic (PDF) and KiCad design files
• ADS1262 datasheet (TI)
• LM2775 charge pump datasheet (TI)

License

• Hardware: CERN Open Hardware Licence Version 2 — Permissive (CERN-OHL-P v2)
• Software / library: MIT License
• Documentation: Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)