SHT21-TR-0.4KS

Introduction to SHT21-TR-0.4KS
- It’s a Sensirion SHT21 family digital humidity and temperature sensor. The “TR-0.4KS” suffix indicates a Tape‑and‑Reel packaging variant for mass production.
- Interface: 2‑wire I2C serial output; default I2C address commonly 0x40.
- Output: digital RH and temperature measurements (commands support single-shot/trigger and continuous modes).
- Power and range: low power operation with a supply voltage of 1.8–3.6 V.
- Features: integrated humidity and temperature sensing with a compact package and robust performance suitable for embedded and portable applications.
- Applications: HVAC and environmental sensing, consumer electronics, IoT, medical devices, agriculture.
- Getting started: refer to the Sensirion SHT21 datasheet for electrical characteristics, timing, and command sequences; use example code from Sensirion or MCU vendors for integration.

Equivalent or replacement parts for the Sensirion SHT21-TR-0.4KS include:
- Sensirion SHT20, SHT25 (same family)
- Sensirion SHT30 / SHT31 (newer upgraded replacements)
- Silicon Labs Si7021
- TE/Measurement Specialties HTU21D
- TI HDC1080
Verify electrical/pin compatibility, accuracy and calibration differences in the datasheets before substituting.

SHT21-TR-0.4KS features:
- Digital humidity and temperature sensor with I2C (2‑wire) interface
- Factory‑calibrated and temperature‑compensated
- Operating range: -40°C to 125°C; humidity 0–100% RH
- Supply voltage: 1.8–3.6 V
- Low power consumption with fast measurement/readout
- Two‑wire serial readout with hold/no‑hold modes
- Small, robust SMD package; suitable for compact designs
- Tape & Reel (TR) packaging for high‑volume assembly
- RoHS compliant; no external calibration required beyond factory data

The SHT21-TR-0.4KS is a 4‑pin SMD sensor. Pin functions are:
- VDD: positive supply voltage (power in)
- GND: ground reference
- SDA: I²C data line (bidirectional serial data)
- SCL: I²C clock line (serial clock input)
(“TR” denotes tape-and-reel packaging for automated assembly.)

- Manufacturer: Sensirion AG (Sensirion)
- What kind of company: A Swiss-based MEMS sensor company that designs and manufactures environmental sensor solutions (e.g., humidity and temperature sensors) for automotive, consumer electronics, medical, and industrial markets.

- Smart home and HVAC systems for humidity/temperature control
- Building automation and industrial monitoring (including clean rooms)
- Consumer electronics and wearables for environmental sensing
- Agriculture and greenhouse climate control
- Automotive cabin climate monitoring
- Medical devices and laboratory equipment environmental sensing
- Food storage and supply-chain humidity/temperature monitoring
Note: SHT21-TR-0.4KS is a compact, low-power digital humidity and temperature sensor (I2C) suitable for space- and power-constrained applications.

SHT21-TR-0.4KS denotes the SHT21 sensor shipped in tape-and-reel (TR) format. The sensor itself is a 3-pin surface-mount device (SMD), typically in a SOT-23-style package.