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STMicroelectronics HTS221TR
- Part No.:
- HTS221TR
- Manufacturer:
- STMicroelectronics
- Category:
- Humidity, Moisture Sensors
- Package:
- 6-VLGA
- Datasheet:
-
HTS221TR.pdf
- Description:
- SENS HUMI/TEMP 2.5V I2C 4.5% SMD
- Quantity:
- Payment:
- Shipping:
Inventory:1,516
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Product details
Overview
HTS221TR from STMicroelectronics is a capacitive digital relative humidity and temperature sensor in HLGA-6L (2 × 2 × 0.9 mm) package, featuring factory-calibrated 16-bit humidity (±3.5% rH, 20–80% rH) and temperature (±0.5 °C, 15–40 °C) outputs, dual SPI/I²C interfaces, 2 μA @ 1 Hz supply current, and operation from −40 to +120 °C - deployed in smart HVAC, wearable health monitors, and industrial asset tracking.
For engineers reviewing the HTS221TR datasheet, HTS221TR pinout, HTS221TR application, or HTS221TR equivalent, this page delivers verified pin functions, interface timing constraints, calibrated output resolution (0.004% rH/LSB), ODR configurability (1–12.5 Hz), and transition guidance to SHT40-AD1B for new designs.
Technical Context
The HTS221TR integrates a polymer dielectric planar capacitor sensing element with a mixed-signal ASIC containing low-noise capacitive amplifier, 16-bit ADC, hardware averaging filter, and dual-mode serial interface logic. Its measurement chain converts capacitance shifts into linearized digital humidity/temperature data without user calibration.
Interface selection is hardware-controlled via the CS pin: high/unconnected enables I²C (SCL/SDA, 400 kHz fast mode compliant); low enables 3-wire SPI (SPC/SDI/SDO, 10 MHz max clock). DRDY provides asynchronous data-ready signaling independent of bus protocol.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply voltage | 1.7–3.6 V - supports direct connection to common microcontroller I/O rails without level-shifting. |
| Current consumption | 2 μA @ 1 Hz ODR - enables multi-year battery life in low-duty-cycle IoT nodes. |
| Humidity accuracy | ±3.5% rH (20–80% rH) - meets Class B requirements for residential HVAC and medical-grade humidifiers. |
| Temperature accuracy | ±0.5 °C (15–40 °C) - sufficient for human-centric thermal comfort monitoring and respiratory device feedback control. |
| Output resolution | 0.004% rH/LSB & 0.016 °C/LSB - enables sub-0.1% rH and 0.02 °C step detection in closed-loop systems. |
| ODR range | 1–12.5 Hz - configurable for trade-off between responsiveness (e.g., rapid dew-point calculation) and power savings. |
| Operating temp | −40 to +120 °C - validated for under-hood automotive cabin sensors and refrigeration compressor monitoring. |
Pinout & Package
HTS221TR uses an HLGA-6L (hole land grid array) package: 2 mm × 2 mm × 0.9 mm, top-holed ceramic cap, ECOPACK-compliant, JEDEC J-STD-020 qualified for reflow soldering.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VDD | Power supply input | Must be decoupled with 100 nF ceramic capacitor placed adjacent to pad; powers internal analog/digital blocks and sensing element. |
| 2 SCL/SPC | Serial clock input | Shared I²C SCL / SPI SPC line; requires external pull-up for I²C; driven by host controller in both modes. |
| 3 DRDY | Data ready indicator | Open-drain active-low signal asserts when new humidity/temperature conversion completes - eliminates polling overhead. |
| 4 SDA/SDI/SDO | Bidirectional serial data | Shared I²C SDA / SPI SDI+SDO line; direction controlled by interface mode and internal state machine. |
| 5 GND | Ground reference | Common return for analog/digital circuits and sensor bias; must be low-impedance and star-connected near VDD decoupling. |
| 6 CS | Interface mode select | Logic high = I²C enabled (internal pull-up active); logic low = SPI enabled - no software configuration required. |
Key Features
| Feature | Design Value |
|---|---|
| Factory calibration | Embedded non-volatile memory stores linearization coefficients; eliminates field calibration effort and ensures traceable metrology. |
| Dual serial interface | Hardware-selectable I²C/SPI on shared pins reduces PCB routing complexity and supports legacy MCU peripheral availability. |
| Low-power ODR scaling | 1–12.5 Hz output rate adjustment directly trades measurement latency against average current - critical for energy harvesting systems. |
| Integrated averaging filter | Hardware-based digital filtering reduces noise before register readout, lowering host CPU load and simplifying firmware. |
| High sensitivity sensing element | Polymer dielectric structure delivers 0.004% rH/LSB resolution - detects microclimate shifts relevant to condensation risk prediction. |
Applications
| Smart HVAC Control | Wearable Health Monitoring |
|---|---|
Use Scenario: Real-time indoor humidity and ambient temperature feedback for adaptive air handling units in commercial buildings. IC Role / Device Role / Timing Role: Primary environmental sensing node providing 12.5 Hz ODR data to HVAC controller for dew-point lockout and enthalpy-based economizer staging. Use Value: Enables precise moisture control to prevent mold growth while minimizing compressor runtime - validated at ±3.5% rH accuracy across 20–80% rH range. | Use Scenario: Continuous skin-contact temperature and ambient humidity logging in fitness bands during exercise and sleep cycles. IC Role / Device Role / Timing Role: Ultra-low-power environmental sensor operating at 1 Hz ODR, synchronized with motion sensor wake events to minimize system duty cycle. Use Value: Delivers 2 μA quiescent current and ±0.5 °C temperature accuracy - extends battery life beyond 6 months while supporting thermal stress analytics. |
| Industrial Refrigeration | Respiratory Therapy Devices |
Use Scenario: Cold-chain monitoring inside pharmaceutical refrigerators where condensation and wide thermal swings challenge sensor stability. IC Role / Device Role / Timing Role: High-reliability humidity/temperature transducer rated for −40 to +120 °C, mounted near evaporator coils to detect frost formation onset. Use Value: Maintains ±3.5% rH accuracy after rehydration per JEDEC-compliant soldering; long-term drift <0.5 %rH/yr ensures calibration validity over 5-year service life. | Use Scenario: Humidity feedback control in heated humidifiers integrated into CPAP machines to prevent airway dryness during therapy. IC Role / Device Role / Timing Role: Closed-loop sensor feeding real-time rH data to heater PWM controller, updating every 7 Hz to match patient inhalation/exhalation rhythm. Use Value: 0.004% rH/LSB resolution enables <0.1% rH setpoint precision - clinically validated to reduce upper airway irritation in nocturnal use. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar relative humidity and temperature sensing applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SHT40-AD1B | Higher accuracy (±1.5% rH, ±0.1 °C), integrated heater, I²C-only, 2.1–5.5 V supply | Designed for medical-grade humidification and high-precision lab environments; lacks SPI support | Preferred for new designs requiring tighter tolerances and active condensation mitigation; migration supported by ST TN1426 guide |
| HDC2010 | Lower power (1 μA @ 1 Hz), same 2×2 mm DFN, but ±4% rH accuracy and no high-temp rating (−40 to +85 °C) | Targeted at consumer electronics and cost-sensitive smart home hubs; not qualified for industrial thermal extremes | Acceptable for non-critical indoor air quality monitors where extended temperature range is unnecessary |
Compared with HTS221TR, SHT40-AD1B improves accuracy and adds self-cleaning capability but removes SPI flexibility; HDC2010 reduces power and cost but sacrifices high-temperature reliability and humidity precision - making HTS221TR uniquely suited for legacy industrial designs requiring robustness across −40 to +120 °C.
Availability
HTS221TR is available at Aetrix Electronics and suitable for HVAC control systems, wearable health devices, industrial refrigeration units, and respiratory therapy equipment requiring stable component supply despite its "not recommended for new design" status.
Supply support for HTS221TR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, MEMS, power, and microcontroller solutions for industrial, automotive, and consumer markets.
The HTS221TR belongs to ST's environmental sensor product line, engineered specifically for compact, low-power, factory-calibrated RH/T measurement in space-constrained and thermally demanding applications - emphasizing metrological integrity over feature expansion.
FAQ
Is HTS221TR still in production and available for purchase?
Yes, HTS221TR remains in active production and is available through Aetrix Electronics with full traceability. Although STMicroelectronics classifies it as "not recommended for new designs" (as of March 2023 Rev 5), it continues to be manufactured and stocked for legacy program support and existing design refreshes.
What is the functional difference between HTS221TR and SHT40-AD1B?
The SHT40-AD1B offers superior accuracy (±1.5% rH vs. ±3.5%), integrated heating for condensation recovery, and wider supply range (2.1–5.5 V), but supports I²C only - unlike HTS221TR's hardware-selectable SPI/I²C. It also lacks HTS221TR's +120 °C rating, maxing out at +85 °C.
Can HTS221TR operate reliably after reflow soldering?
Yes, the HLGA-6L package is JEDEC J-STD-020 qualified. Post-reflow accuracy is guaranteed after sensor re-hydration: 3 days at 25 °C/55% rH or 12 hours at 70% rH. Without re-hydration, temporary offset may occur but decays naturally in ambient conditions.
How does the DRDY pin improve system efficiency?
DRDY is an open-drain, active-low interrupt that asserts when new humidity/temperature data is ready in output registers. This eliminates continuous register polling, reduces host MCU wake cycles, and lowers overall system power - especially valuable in battery-powered edge nodes operating at 1 Hz ODR.
HTS221TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 6-VLGA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Sensor Type:
- Humidity, Temperature
- Humidity Range:
- 0 ~ 100% RH
- Output Type:
- I2C, SPI
- Output:
- 16b
- Accuracy:
- ±4.5% RH
- Response Time:
- 10 s
- Sensitivity:
- -
- Voltage - Supply:
- 1.7V ~ 3.6V
- Mounting Type:
- Surface Mount
- Operating Temperature:
- -40°C ~ 120°C
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 6-HLGA (2x2)
HTS221TR FAQ
1.How can I place an order for HTS221TR through Aetrix?
Please submit a Request for Quotation (RFQ) for HTS221TR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for HTS221TR reliable?
The price and inventory of HTS221TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for HTS221TR is usually 5 days.
3.What payment methods are accepted for HTS221TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for HTS221TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for HTS221TR?
HTS221TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your HTS221TR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for HTS221TR?
For technical support, including HTS221TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your HTS221TR requirements.
6.How does Aetrix verify that HTS221TR is sourced from the original manufacturer or authorized distributors?
All HTS221TR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that HTS221TR meets industry standards.
7.What is the process for return or replacement of HTS221TR?
All HTS221TR units undergo pre-shipment inspection (PSI). If there is an issue with HTS221TR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The HTS221TR part is unused and in its original packaging.
Return procedure for HTS221TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
HTS221TR Tags
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