## Overview of SHT43-BDCB-R3 The **SHT43-BDCB-R3** is a high-precision digital temperature and humidity sensor manufactured by **Sensirion**. It belongs to the 4th generation (SHT4x series) and is specifically designed for high-reliability applications, often used in automotive or demanding industrial environments. --- ### Key Technical Specifications | Parameter | Specification | Notes | | :--- | :--- | :--- | | **Supply Voltage (VDD)** | 1.08 V to 3.6 V | Compatible with 1.8V, 2.5V, and 3.3V systems | | **Idle Current** | 80 nA (typical) | Optimized for battery-powered devices | | **Average Current** | 2.3 µA | At 1 measurement per second | | **I2C Speed** | Up to 1 MHz | Supports Fast Mode Plus | | **RH Accuracy** | ±1.8% RH | Typical range 25-75% RH | | **Temp. Accuracy** | ±0.2 °C | Typical range 0-60 °C | | **Package Type** | DFN-4 | 1.5 x 1.5 x 0.5 mm footprint | --- ### Functional Electronic Components #### 1. The Sensor Elements The device utilizes Sensirion's proprietary **CMOSens® Technology**. * **Capacitive Humidity Sensor:** Measures changes in capacitance of a polymer dielectric layer as it absorbs water molecules. * **Bandgap Temperature Sensor:** A precision PTAT (Proportional To Absolute Temperature) circuit integrated into the silicon. #### 2. Signal Processing ASIC The internal Application-Specific Integrated Circuit (ASIC) performs several critical roles: * **ADC (Analog-to-Digital Converter):** Converts the raw analog signals from the sensors into high-resolution digital data. * **Calibration Memory:** Each unit is individually calibrated. The correction factors are stored in non-volatile memory and applied automatically during measurement. * **Digital Interface:** Handles the I2C communication protocol, including device addressing and CRC (Cyclic Redundancy Check) checksum generation. #### 3. Integrated Power Management & Heater * **LDO Regulators:** Internal regulators allow the chip to operate stably across a wide voltage range (1.08V - 3.6V). * **On-chip Heater:** A programmable power heater is integrated to remove condensed water or creep effects in high-humidity environments. It can be activated via I2C commands at different power levels and durations. --- ### Pin Configuration (DFN-4) ```text +-------+ SCL | 1 4 | SDA | [P] | VSS | 2 3 | VDD +-------+ (Bottom View / P = Thermal Pad) ``` 1. **SCL:** Serial Clock (I2C input). 2. **VSS:** Ground. 3. **VDD:** Supply Voltage. 4. **SDA:** Serial Data (I2C bidirectional). --- ### Application Circuit Example To integrate the SHT43 into a circuit, minimal external components are required: ```c // Typical Schematic Requirements: // 1. VDD to VSS: 100nF decoupling capacitor (placed close to the chip). // 2. SDA/SCL lines: 1kOhm to 10kOhm pull-up resistors (connected to VDD). // 3. Thermal Pad: Should be left floating or connected to VSS. ``` ---