HX711 24-Bit ADC Complete Guide for Load Cells and Weighing Systems

FREE-SKY (HK) ELECTRONICS CO.,LIMITED / 06-08 21:31

The HX711 is a 24-bit analog-to-digital converter designed for load cells and electronic weighing systems. It is commonly used when a microcontroller needs to read very small signals from a strain gauge or Wheatstone bridge load cell. Since load cells produce tiny voltage changes when weight or force is applied, the signal must be amplified and converted into digital data before it can be used. The HX711 solves this problem by combining a low-noise programmable gain amplifier, a high-resolution ADC, a voltage regulator, and a simple two-wire digital interface in one compact IC.

Catalog

1. HX711 Pinout Details

2. HX711 Features and Specifications

3. HX711 Internal Architecture

4. How to Utilize HX711

5. PCB Board of HX711

6. Applications of HX711

7. HX711 vs ADS1232 vs NAU7802

8. HX711 Mechanical Dimensions

9. Manufacturer

HX711 Pinout Details

Pin No.	Pin Name	Description
1	VSUP	Power supply input for the internal regulator.
2	BASE	Regulator control output used to drive an external transistor for voltage regulation.
3	AVDD	Analog power supply output for the HX711 analog circuitry and load cell excitation.
4	VFB	Regulator feedback input used to control the internal voltage regulator.
5	AGND	Analog ground reference.
6	VBG	Bandgap reference bypass pin for reference voltage stabilization.
7	INNA	Channel A negative differential input.
8	INPA	Channel A positive differential input.
9	INNB	Channel B negative differential input.
10	INPB	Channel B positive differential input.
11	PD_SCK	Power-down and serial clock input. Controls data readout and power-down functions.
12	DOUT	Serial data output. Indicates conversion readiness and outputs ADC data.
13	XO	Crystal oscillator output or external clock connection.
14	XI	Crystal oscillator input or external clock input.
15	RATE	Output data rate selection input. Low = 10 SPS, High = 80 SPS.
16	DVDD	Digital power supply for the digital interface circuitry.

HX711 Features and Specifications

Category	Specification
Device Type	24-bit Analog-to-Digital Converter (ADC) for load cell and weigh scale applications
Input Channels	Two selectable differential input channels (Channel A and Channel B)
Programmable Gain Amplifier (PGA)	Integrated low-noise PGA with selectable gains of 32, 64, and 128
Channel A Gain Options	64 or 128
Channel B Gain Option	32
Voltage Regulator	On-chip power supply regulator for load cell excitation and analog circuitry
Oscillator	Built-in oscillator; optional external crystal or clock source supported
Power-On Reset	Integrated automatic power-on-reset function
Digital Interface	Simple two-wire serial interface using DOUT and PD_SCK pins
Control Method	Pin-driven control; no internal registers or programming required
Output Data Rate	Selectable 10 SPS or 80 SPS
Noise Rejection	Simultaneous 50 Hz and 60 Hz power-line noise rejection
Resolution	24-bit
Current Consumption (Normal Mode)	< 1.5 mA (including on-chip regulator)
Current Consumption (Power-Down Mode)	< 1 µA
Operating Supply Voltage	2.6 V to 5.5 V
Operating Temperature Range	-40°C to +85°C
Power-Down Function	Supported through PD_SCK control
External Clock Support	Yes
Internal Oscillator	Yes
Package Type	16-pin SOP-16 (SOP-16L) package
Typical Sensor Interface	Wheatstone bridge load cells and strain gauges

HX711 Internal Architecture

How to Utilize HX711

The circuit diagram below shows a typical weighing system that uses a load cell and the ADS1232

NAU7802
Manufacturer	Avia Semiconductor	Texas Instruments	Nuvoton Technology
Device Type	24-bit Load Cell ADC	24-bit Precision ADC	24-bit Load Cell ADC
ADC Architecture	Sigma-Delta ADC	Sigma-Delta ADC	Sigma-Delta ADC
Resolution	24-bit	24-bit	24-bit
Input Channels	2 Differential Channels	1 Differential Channel	2 Differential Channels
Programmable Gain	32, 64, 128	1, 2, 64, 128	1 to 128
Typical Interface	DOUT + PD_SCK (2-wire)	SPI-like Interface	I²C
Data Output Method	Serial Data Stream	Digital Serial Interface	I²C Register Access
Data Rates	10 SPS, 80 SPS	10 SPS, 80 SPS	10, 20, 40, 80, 320 SPS
Internal Oscillator	Yes	Yes	Yes
External Clock Support	Yes	Yes	No
Integrated PGA	Yes	Yes	Yes
Integrated Voltage Regulator	Yes	No	Yes
Temperature Sensor	No	No	Yes
Internal Calibration	Basic	Advanced	Advanced
Offset Calibration	Limited	Yes	Yes
Gain Calibration	Limited	Yes	Yes
Power Supply Range	2.6V – 5.5V	2.7V – 5.3V	2.7V – 5.5V
Typical Current Consumption	<1.5 mA	~1.1 mA	~0.7 mA
Power-Down Current	<1 µA	<1 µA	<1 µA
Noise Rejection	50/60 Hz	50/60 Hz	50/60 Hz
Internal Registers	No	Limited	Extensive Register Set
Microcontroller Integration	Very Easy	Moderate	Easy
Arduino Library Support	Excellent	Good	Excellent
Raspberry Pi Support	Good	Good	Excellent
ESP32 Support	Excellent	Good	Excellent
External Components Required	Very Few	Moderate	Few
Measurement Accuracy	Good	Very High	Very High
Industrial Precision	Medium	High	High
Cost	Lowest	Highest	Medium
Typical Module Availability	Very Common	Less Common	Common
Best Application	Hobby scales and low-cost projects	Industrial weighing and precision instruments	Smart scales, IoT devices, and advanced weighing systems

HX711 Mechanical Dimensions

Manufacturer

The HX711 is manufactured by Avia Semiconductor, a company specializing in precision analog and mixed-signal integrated circuits for sensor and measurement applications. The company has strong capabilities in designing and producing high-resolution sigma-delta ADCs, low-noise programmable gain amplifiers, and power management circuits integrated into compact semiconductor devices. The HX711 combines a 24-bit ADC, PGA, voltage regulator, oscillator, and digital interface into a single chip, demonstrating Avia Semiconductor's expertise in low-noise analog design and cost-effective mass production.