> For the complete documentation index, see [llms.txt](https://docs.acrome.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.acrome.net/smd-applications/boardoza-sensors/hx711-analog-digital-converter-adc.md).

# HX711 Analog Digital Converter (ADC)

### Overview

The Boardoza HX711 is a precision 24-bit analog-to-digital converter designed specifically for weigh scales and industrial control applications to interface directly with a bridge sensor. Built around the Avia Semiconductor HX711 architecture, this module integrates a low-noise programmable gain amplifier (PGA) and a regulated power supply, providing a complete "front-end" solution for load cells.

Unlike general-purpose ADCs, the HX711 is optimized for small-signal differential measurements. It eliminates the need for external active components by incorporating on-chip power supply regulators and an on-chip oscillator, drastically reducing the bill of materials and PCB footprint for high-precision force sensing systems.

***

|                                                            Front Side                                                           |                                                           Back Side                                                           |
| :-----------------------------------------------------------------------------------------------------------------------------: | :---------------------------------------------------------------------------------------------------------------------------: |
| ![HX711 Front](https://github.com/Boardoza/Boardoza_HX711_Load_Cell_Amplifier_Breakout_Board/raw/main/assets/HX711%20Front.png) | ![HX711 Back](https://github.com/Boardoza/Boardoza_HX711_Load_Cell_Amplifier_Breakout_Board/raw/main/assets/HX711%20Back.png) |

<div align="left"><figure><img src="/files/A299EENm4ReyTF1As2ym" alt="" width="375"><figcaption></figcaption></figure></div>

***

### Core Technical Specifications

The module is defined by the following operational parameters:

* Resolution: 24-bit output precision, capable of resolving extremely minute voltage changes typical of strain gauge bridges.
* Input Channels: Features two selectable differential input channels (Channel A and Channel B). Channel A is programmable with a gain of 64 or 128, while Channel B has a fixed gain of 32.
* Low-Noise PGA: The integrated Programmable Gain Amplifier enables direct interfacing with low-output sensors (e.g., 2mV/V load cells) without requiring external instrumentation amplifiers.
* Data Rate: User-selectable output data rate of either 10 samples per second (SPS) for high stability or 80 SPS for faster response times.
* Power Supply Rejection: Simultaneous 50Hz and 60Hz supply rejection ensures measurement stability in electrically noisy industrial environments.
* Operating Voltage: Supports a wide supply range from 2.6V to 5.5V, making it compatible with both 3.3V and 5V logic systems.
* Current Consumption: Low operating current (<1.5 mA) and an integrated power-down mode (<1 µA) suitable for battery-powered scales.

***

### Key Engineering Features

#### Specialized Bridge Interface

The module is engineered to drive Wheatstone bridge sensors directly. It provides the excitation voltage (E+ and E-) and reads the differential signal voltage (A+ and A-). The on-chip analog power regulator simplifies the power distribution network, ensuring that the excitation voltage remains stable relative to the ADC reference, which is critical for ratiometric measurement accuracy.

#### Digital Interface Protocol

The HX711 utilizes a custom two-wire serial interface (Clock and Data) that is similar to, but not compatible with, standard SPI. This "bit-banging" protocol allows the host microcontroller to retrieve the 24-bit conversion result and simultaneously configure the gain and channel selection for the *next* conversion cycle via the number of clock pulses sent.

#### On-Chip Oscillator

The internal on-chip oscillator requires no external crystal or capacitor, simplifying board layout and reducing susceptibility to EMI. This robust clock generation ensures consistent timing for the Sigma-Delta modulator and digital filter stages.

***

### Board Pinout

#### J1 Connector

<table><thead><tr><th width="149.5703125" align="center">Pin Number</th><th align="center">Pin Name</th><th>Description</th></tr></thead><tbody><tr><td align="center">1</td><td align="center">VCC</td><td>2.7V - 5.5V Power Input</td></tr><tr><td align="center">2</td><td align="center">VDD</td><td>2.7V - 5.5V Power Input</td></tr><tr><td align="center">3</td><td align="center">DAT</td><td>Serial Data Output</td></tr><tr><td align="center">4</td><td align="center">CLK</td><td>Serial Clock Input</td></tr><tr><td align="center">5</td><td align="center">GND</td><td>Ground</td></tr></tbody></table>

#### J2 Connector

<table><thead><tr><th width="150.0234375" align="center">Pin Number</th><th align="center">Pin Name</th><th>Description</th></tr></thead><tbody><tr><td align="center">1</td><td align="center">B+</td><td>Positive Signal (Second Channel)</td></tr><tr><td align="center">2</td><td align="center">B-</td><td>Negative Signal (Second Channel)</td></tr></tbody></table>

#### J3 Connector (Load Cell Interface)

<table><thead><tr><th width="149.87890625" align="center">Pin Number</th><th align="center">Pin Name</th><th>Description</th></tr></thead><tbody><tr><td align="center">1</td><td align="center">RED/E+</td><td>+ Excitation</td></tr><tr><td align="center">2</td><td align="center">BLK/E-</td><td>- Excitation</td></tr><tr><td align="center">3</td><td align="center">WHT/A-</td><td>- Signal</td></tr><tr><td align="center">4</td><td align="center">GRN/A+</td><td>+ Signal</td></tr></tbody></table>

#### JP1 Jumper Settings

<table><thead><tr><th width="176.27734375" align="center">Pin Configuration</th><th>Data Rate</th></tr></thead><tbody><tr><td align="center">1-2</td><td>80 Samples per Second (SPS)</td></tr><tr><td align="center">2-3</td><td>10 Samples per Second (SPS)</td></tr></tbody></table>

***

### Applications

* Electronic Scales: Kitchen scales, bathroom scales, and postage meters.
* Industrial Weighing: Hopper scales, platform scales, and conveyor belt monitoring.
* Force Sensing: Strain gauge measurement for structural health monitoring.
* Tactile Sensors: Robotics pressure sensing and grip force feedback.

***

### Board Dimensions:

![HX711 Dimension](https://github.com/Boardoza/Boardoza_HX711_Load_Cell_Amplifier_Breakout_Board/raw/main/assets/HX711%20Dimension.png)

***

{% hint style="info" %}
Ready to integrate? You can purchase the **HX711 Analog Digital Converter** directly from our [Online Store](https://www.robotshop.com/products/acrome-load-cell-amplifier-board-hx711?qd=97fe14d7a62dbe4d77087959586fffc1). Worldwide shipping is available for engineering samples and production batches.
{% endhint %}