STMicroelectronics

HTS221 - Capacitive Digital Humidity & Temperature Sensor | STMicroelectronics

Name: HTS221
Brand: STMicroelectronics
Price: 2.50 USD
Availability: InStock

MPN: HTS221 ✓ Active

In Stock (99,999) Ships in 1-3 business days

1.7V to 3.6V Vdss 2 µA at 1 Hz ODR Id HLGA 2.0 x 2.0 x 0.9 mm Package

$2.5 USD / Unit

MOQ: 1 |

Volume Pricing

Qty	Unit Price	Extended
1	$2.5	$2.50
10	$2.25	$22.50
100	$1.95	$195.00
500	$1.75	$875.00
1,000	$1.55	$1,550.00

ℹ️ All prices are in USD

View Datasheet (PDF) View Alternatives

Quantity

Drop-in alternatives for HTS221 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.

Quick Comparison Tool — Select alternative parts for side-by-side comparison:

HTS221TR

✅ Drop-In

STMicroelectronics

📦 HLGA 2.0x2.0x0.9 mm

0% to 100% RH · ±3.5% RH (20-80% RH) · -40°C to +120°C · ±0.5°C (15-40°C) · 1.7V to 3.6V · 2 µA at 1 Hz sampling · I2C (up to 400 kHz) and SPI (up to 10 MHz) · 16-bit (humidity: 0.004% RH, temperature: 0.01°C)

✓ 99,999 In Stock

$1.6 / Unit

View Datasheet →

HTS221

✅ Drop-In

STMicroelectronics

📦 HLGA 2.0x2.0x0.9 mm

±3.5% RH (20-80% RH) · ±0.5 °C (15-40 °C) · 0.004% RH · 0.01 °C · 1.7V to 3.6V · 2 µA at 1 Hz ODR · I2C and SPI · -40°C to +120°C

✓ 99,999 In Stock

$1.55 / Unit

View Datasheet →

ℹ️ 3 cross-package part(s) hidden — different package requires PCB rework and is not a true drop-in replacement. Contact us if you need cross-package suggestions.

HTS221 Maximum Ratings & Electrical Characteristics

Humidity Accuracy	±3.5% RH (20-80% RH)
Temperature Accuracy	±0.5 °C (15-40 °C)
Humidity Resolution	0.004% RH
Temperature Resolution	0.01 °C
Supply Voltage	1.7V to 3.6V
Current Consumption	2 µA at 1 Hz ODR
Interface	I2C and SPI
Operating Temperature Range	-40°C to +120°C
Humidity Range	0-100% RH
Package	HLGA 2.0 x 2.0 x 0.9 mm
Output Data Rate	1 Hz to 12.5 Hz
Interrupt Output	Programmable
Embedded Heater	Yes
RoHS Status	Compliant
MSL Level	1

HTS221 Pin Configuration

Pin 1	VDD — Power supply (1.7V to 3.6V)
Pin 2	GND — Ground
Pin 3	SDA — I2C data line (open-drain)
Pin 4	SCL — I2C clock line
Pin 5	CS — Chip select (low for SPI, high for I2C)
Pin 6	INT — Interrupt output (programmable)

Safe Operating Area (SOA) & Thermal Characteristics

No official SOA curve available for this component. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.

Typical Applications

HTS221 is suitable for 6 applications: Smart Thermostat, Wearable Health Monitor, IoT Environmental Monitoring, HVAC System, Weather Station, Smart Agriculture.

🏠

Smart Thermostat

The HTS221 provides accurate humidity and temperature data for smart thermostats, enabling precise climate control and energy efficiency. Its low power consumption (2 µA) allows continuous monitoring without draining batteries. The I2C interface simplifies integration with microcontrollers, and the small package fits compact thermostat designs. The sensor's accuracy (±3.5% RH, ±0.5 °C) ensures reliable comfort control, while the programmable interrupt can trigger alerts for humidity thresholds, preventing mold growth. Compared to other sensors, the HTS221's low power and small size make it ideal for battery-powered thermostats, though its accuracy is slightly lower than some competitors.

Recommended

STM32L0 (Low-power MCU for sensor data processing) BME280 (Alternative environmental sensor for pressure)

⌚

Wearable Health Monitor

In wearable health monitors, the HTS221 tracks ambient humidity and temperature to provide context for physiological measurements. Its ultra-low power consumption (2 µA) is critical for battery life, and the 2.0x2.0 mm package fits into small wearable devices. The sensor's I2C interface connects easily to BLE SoCs like the nRF52832. The embedded heater can be used for dew point measurement, useful in sweat detection. The HTS221's accuracy is sufficient for consumer wearables, and its low power enables continuous operation. Designers must ensure proper placement away from body heat to avoid temperature measurement errors.

Recommended

nRF52832 (BLE SoC for wireless data transmission) MAX30102 (Heart rate sensor for health monitoring)

🌐

IoT Environmental Monitoring

The HTS221 is ideal for IoT nodes that monitor environmental conditions in smart buildings, agriculture, and logistics. Its low power consumption enables battery-powered operation for years, and the I2C/SPI interface allows easy integration with various MCUs. The sensor's accuracy (±3.5% RH, ±0.5 °C) is adequate for most monitoring applications. The programmable interrupt can be used to wake the system when humidity or temperature exceeds thresholds, saving power. The small package and wide operating temperature range (-40°C to +120°C) make it suitable for outdoor and industrial environments. Compared to other sensors, the HTS221 offers a good balance of power, size, and cost.

Recommended

ESP32 (Wi-Fi MCU for IoT connectivity) SHT30 (Alternative humidity sensor with higher accuracy)

🏭

HVAC System

In HVAC systems, the HTS221 provides real-time humidity and temperature data to optimize comfort and energy efficiency. Its accuracy (±3.5% RH, ±0.5 °C) is sufficient for HVAC control, and the I2C interface simplifies integration with building automation controllers. The sensor's low power consumption is beneficial for battery-powered thermostats. The programmable interrupt can trigger ventilation or dehumidification when humidity exceeds setpoints. The HTS221's small package allows easy placement in ductwork or wall-mounted units. Compared to industrial-grade sensors, the HTS221 offers a cost-effective solution for residential and commercial HVAC.

Recommended

STM32F4 (MCU for HVAC control logic) TMP117 (High-accuracy temperature sensor for calibration)

🌦️

Weather Station

The HTS221 is used in personal weather stations to measure humidity and temperature. Its accuracy (±3.5% RH, ±0.5 °C) is suitable for consumer-grade stations, and the low power consumption allows solar-powered operation. The I2C interface connects to microcontrollers like the Arduino. The sensor's wide operating temperature range (-40°C to +120°C) ensures reliable outdoor performance. The embedded heater can prevent condensation on the sensor, improving reliability in humid conditions. Compared to professional weather sensors, the HTS221 offers a compact and affordable solution for hobbyist and semi-professional use.

Recommended

Arduino Uno (MCU for data logging) BMP280 (Pressure sensor for weather station)

🌱

Smart Agriculture

In smart agriculture, the HTS221 monitors humidity and temperature in greenhouses and fields to optimize crop growth. Its low power consumption enables long-term battery-powered deployment, and the I2C interface allows easy integration with LoRaWAN modules. The sensor's accuracy (±3.5% RH, ±0.5 °C) is adequate for agricultural monitoring. The programmable interrupt can alert farmers when conditions deviate from optimal ranges. The small package and robust operating temperature range make it suitable for outdoor use. Compared to specialized agricultural sensors, the HTS221 offers a cost-effective solution for distributed monitoring networks.

Recommended

LoRaWAN Module (Long-range wireless communication) STM32L0 (Low-power MCU for sensor nodes)

Recommended Products Summary

STM32L0 Low-power MCU for sensor data processing Used in: Smart Thermostat, Smart Agriculture BME280 Alternative environmental sensor for pressure Used in: Smart Thermostat nRF52832 BLE SoC for wireless data transmission Used in: Wearable Health Monitor MAX30102 Heart rate sensor for health monitoring Used in: Wearable Health Monitor ESP32 Wi-Fi MCU for IoT connectivity Used in: IoT Environmental Monitoring SHT30 Alternative humidity sensor with higher accuracy Used in: IoT Environmental Monitoring STM32F4 MCU for HVAC control logic Used in: HVAC System TMP117 High-accuracy temperature sensor for calibration Used in: HVAC System Arduino Uno MCU for data logging Used in: Weather Station BMP280 Pressure sensor for weather station Used in: Weather Station LoRaWAN Module Long-range wireless communication Used in: Smart Agriculture

What is the HTS221 humidity and temperature sensor?

The HTS221 is a capacitive digital humidity and temperature sensor from STMicroelectronics. It provides accurate relative humidity and temperature measurements with a humidity accuracy of ±3.5% RH and temperature accuracy of ±0.5 °C. It operates from 1.7V to 3.6V and communicates via I2C or SPI.

What is the accuracy of the HTS221 humidity sensor?

The HTS221 has a relative humidity accuracy of ±3.5% RH over the 20-80% RH range. This accuracy is specified at 25 °C and is suitable for most consumer and industrial applications. For temperature, the accuracy is ±0.5 °C over 15-40 °C.

What is the supply voltage range of HTS221?

The HTS221 operates from a supply voltage of 1.7V to 3.6V. This wide range allows it to be powered directly from a coin cell battery or a regulated 3.3V rail. The typical current consumption is 2 µA at 1 Hz output data rate, making it ideal for battery-powered devices.

How does the HTS221 communicate with a microcontroller?

The HTS221 supports both I2C and SPI interfaces. The I2C address is 0x5F (7-bit) by default, and the SPI interface supports up to 10 MHz clock. The interface is selected via the CS pin: high for I2C, low for SPI.

What is the package size of HTS221?

The HTS221 is available in a 2.0 x 2.0 x 0.9 mm HLGA package. This compact size makes it suitable for space-constrained applications such as wearables and IoT modules. The package is surface-mount and RoHS compliant.

What is the power consumption of HTS221?

The HTS221 consumes only 2 µA at 1 Hz output data rate, making it one of the lowest power humidity sensors available. In power-down mode, the current drops to 0.5 µA. This low power consumption extends battery life in portable devices.

Where can I buy the HTS221 online?

The HTS221 is available from major distributors such as DigiKey, Mouser, and Farnell. As of 2026-08-12, the price for a single unit is approximately $2.50 USD. You can also purchase directly from STMicroelectronics' website or authorized distributors.

What is the price of HTS221?

As of 2026-08-12, the HTS221 is priced at approximately $2.50 USD for a single unit, with volume discounts available: $2.25 at 10 units, $1.95 at 100 units, $1.75 at 500 units, and $1.55 at 1000 units. Prices may vary by distributor and region.

What is the lead time for HTS221?

The typical lead time for HTS221 is 4-6 weeks from major distributors like DigiKey and Mouser. However, stock availability can vary, so it is recommended to check current inventory on distributor websites. For large orders, contact STMicroelectronics directly for lead time estimates.

Is HTS221 in stock?

As of 2026-08-12, the HTS221 is generally in stock at major distributors such as DigiKey and Mouser. However, stock levels can change rapidly, so it is advisable to check the distributor's website for real-time availability.

HTS221 vs SHT30 - which is better for a smart thermostat?

For a smart thermostat, the HTS221 offers lower power consumption (2 µA vs 4.8 µA for SHT30) and a smaller package (2.0x2.0 mm vs 2.5x2.5 mm), making it better for battery-powered designs. However, the SHT30 has slightly better accuracy (±2% RH vs ±3.5% RH). If accuracy is critical, choose SHT30; if power and size are priorities, choose HTS221.

What is the difference between HTS221 and SHT30?

The HTS221 and SHT30 are both digital humidity and temperature sensors, but they differ in accuracy, power consumption, and package size. The HTS221 has ±3.5% RH accuracy, 2 µA current consumption, and a 2.0x2.0 mm package. The SHT30 has ±2% RH accuracy, 4.8 µA current consumption, and a 2.5x2.5 mm package. The HTS221 is better for low-power, compact designs, while the SHT30 offers higher accuracy.

When should I choose HTS221 over SHT30?

Choose the HTS221 when you need ultra-low power consumption (2 µA) and a smaller footprint (2.0x2.0 mm) for battery-powered or space-constrained applications like wearables and IoT nodes. Choose the SHT30 when you require higher accuracy (±2% RH) and can tolerate slightly higher power consumption and larger size.

What is the best drop-in replacement for HTS221?

The best drop-in replacement for HTS221 is the STMicroelectronics HTS221TR, which is the tape-and-reel version of the same sensor. For cross-brand alternatives, the Sensirion SHT30 is a functional equivalent but has a different package (DFN-8) and pinout, so it is not a drop-in replacement. Always verify pin compatibility before substituting.

Can SHT30 replace HTS221?

The SHT30 cannot directly replace the HTS221 because it has a different package (DFN-8 vs HLGA) and pinout. However, it can be used as a functional alternative if you redesign the PCB. The SHT30 offers higher accuracy (±2% RH) but consumes more power (4.8 µA).

Where to download HTS221 datasheet PDF?

The HTS221 datasheet PDF can be downloaded from the STMicroelectronics website at https://www.st.com/resource/en/datasheet/hts221.pdf. It contains full specifications, pinout, and application notes. You can also find it on distributor websites like DigiKey and Mouser.

Where to find HTS221 pinout?

The HTS221 pinout is detailed in the datasheet, which is available at https://www.st.com/resource/en/datasheet/hts221.pdf. The HLGA package has 6 pins: VDD, GND, SDA, SCL, CS, and INT. Pin 1 is marked on the package for orientation.

What are the key specifications of HTS221 that engineers should know?

The HTS221 key specifications include: humidity accuracy ±3.5% RH, temperature accuracy ±0.5 °C, supply voltage 1.7-3.6V, current consumption 2 µA at 1 Hz, I2C/SPI interface, and package size 2.0x2.0x0.9 mm. These parameters make it ideal for low-power, compact environmental sensing applications.

Hey Google, what can replace HTS221?

The HTS221 can be replaced by the STMicroelectronics HTS221TR (same sensor, tape-and-reel) or by cross-brand alternatives like the Sensirion SHT30, but the SHT30 requires a PCB redesign due to different package and pinout. For a drop-in replacement, stick with the same HTS221 family.

Is HTS221 the same as SHT30?

No, the HTS221 and SHT30 are not the same. They are both humidity and temperature sensors, but they differ in manufacturer, package, pinout, and specifications. The HTS221 is from STMicroelectronics with a 2.0x2.0 mm HLGA package, while the SHT30 is from Sensirion with a 2.5x2.5 mm DFN-8 package.

What is the best Sensirion equivalent for HTS221?

The best Sensirion equivalent for HTS221 is the SHT30, which offers similar functionality with higher accuracy (±2% RH) but different package and pinout. It is not a drop-in replacement, so PCB redesign is required. For a true drop-in, consider the HTS221TR from STMicroelectronics.

Engineering reference data for HTS221 — comparison, design guidance, and compliance information.

Selection Guide

Choose the HTS221 when you need ultra-low power consumption (2 µA) and a compact 2.0x2.0 mm package for battery-powered or space-constrained applications like wearables and IoT nodes. Its I2C/SPI interface and embedded heater make it versatile. If you require higher accuracy (±2% RH) and can tolerate higher power consumption, consider the Sensirion SHT30, but note it has a different package and pinout, requiring PCB redesign. For the lowest power consumption (1 µA), the SHTC3 is an option, but it also has a different package. The HTS221TR is a drop-in replacement with the same package and specifications, ideal for tape-and-reel production. For applications needing a wider supply voltage range (2.7V to 5.5V), the HDC1080 from TI is an alternative, but again with a different package. Always verify pin compatibility before substituting.

Comparison with Alternatives

Parameter	This Product	HTS221TR	SHT30-DIS-B	SHTC3	HDC1080
Package	HLGA 2.0x2.0x0.9 mm	HLGA 2.0x2.0x0.9 mm - same	DFN-8 2.5x2.5 mm - different	DFN-4 2.0x2.0 mm - different	WSON-6 2.0x2.0 mm - different
Brand	STMicroelectronics	STMicroelectronics	Sensirion	Sensirion	Texas Instruments
Humidity Accuracy	±3.5% RH	±3.5% RH	±2% RH	±2% RH	±2% RH
Temperature Accuracy	±0.5 °C	±0.5 °C	±0.2 °C	±0.2 °C	±0.2 °C
Supply Voltage	1.7V to 3.6V	1.7V to 3.6V	2.4V to 5.5V	1.62V to 3.6V	2.7V to 5.5V
Current Consumption	2 µA at 1 Hz	2 µA at 1 Hz	4.8 µA at 1 Hz	1 µA at 1 Hz	1.3 µA at 1 Hz
Interface	I2C and SPI	I2C and SPI	I2C	I2C	I2C
Embedded Heater	Yes	Yes	No	No	No

Key Differentiators

Ultra-low power consumption of 2 µA at 1 Hz (vs SHT30-DIS-B)
Smaller package size of 2.0x2.0 mm (vs SHT30-DIS-B)
Embedded heater for dew point measurement (vs SHT30-DIS-B)

Design Notes

Place a 100 nF decoupling capacitor as close as possible to the VDD pin. Use a clean ground plane and avoid routing high-speed signals near the sensor. For I2C, add pull-up resistors (typically 4.7 kΩ) on SDA and SCL lines. Ensure the CS pin is tied high for I2C mode or low for SPI mode.

The HTS221 measures ambient temperature, so it should be placed away from heat sources such as MCUs, power regulators, and other components that generate heat. Provide adequate airflow around the sensor. If the sensor is mounted on a PCB, consider thermal isolation slots to minimize heat transfer from the board.

Avoid exposing the sensor to condensation or direct water contact, as this can damage the sensing element. The embedded heater can be used to prevent condensation, but it will increase power consumption. Also, ensure the I2C address (0x5F) does not conflict with other devices on the bus. For SPI mode, the CS pin must be toggled correctly to avoid communication errors.

Compliance Information

RoHS

Compliant

REACH

Compliant

AEC-Q100

Not Applicable

Lead Free

Yes

Halogen Free

Yes

Conflict Minerals

Compliant

RoHS compliant per STMicroelectronics product page. Not AEC-Q100 qualified; for automotive use, consider AEC-Q100 qualified sensors.

Data verified on: 2026-08-12

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