7Semi SHT45 Humidity & Temperature Sensor Breakout Board with 4-Pin Connector

Overview

The breakout is based on the Sensirion SHT45 digital humidity and temperature sensor, a high-accuracy environmental sensor from the SHT4x series.

• Measures:

  • Temperature

  • Relative Humidity

   

• Provides fully calibrated digital output via I2C

• Designed for precision applications requiring very low error and high stability

Compared to earlier SHT sensors, the SHT45 offers higher accuracy and better long-term reliability.

Working Principle

The sensor integrates two sensing technologies:

Temperature Measurement

• Based on a bandgap temperature sensor

• Provides accurate temperature readings

• Used for internal comp

Humidity Measurement

• Uses a capacitive polymer sensing element

• Absorbs water vapor changes capacitance

• Internal ADC converts this into digital RH value

Both measurements are corrected using factory calibration coefficients stored in memory.

Measurement Characteristics

Temperature

• Range: 40C to +125C

• Accuracy: 0.1C (typical)

Humidity

• Range: 0% to 100% RH

• Accuracy: 1.0% RH (typical)

Resolution

• High-resolution 16-bit digital output

Among the most accurate sensors in its class.

Electrical Characteristics

• Supply voltage: 1.08V to 3.6V~0.4 A

• Measurement: ~0.51 mA

Extremely low power consumption suitable for battery-operated devices.

Communication Interface

• Interface: I2C (two-wire digital communication)

• Fixed I2C address: 0x44

• Command-based operation (simple read commands)

No complex register mapping required.

Internal Features

Factory Calibration

• Each sensor individually calibrated

• Outputs:

  • Direct temperature (C)

  • Direct humidity (%RH)

Integrated Heater

• Built-in micro-heater

• Used for:

  • Removing condensation

  • Preventing moisture buildup

  • Self-w Drift

    • Excellent long-term stability

    • Minimal recalibration needed

    Fast Measurement Time

    • Measurement duration: ~110 ms

    4-Pin Connector Interface

    Typical pin configuration:

    • VCC Power supply

    • GND Ground

    • SDA I2C data

    • SCL I2C clock

    The 4-pin connector simplifies:

    • Wiring

    • Integration into embedded systems

    Physical Characteristics

    • Sensor IC size: ~1.5 1.5 0.5 mm

    • Breakout board: compact form factor

    • Designed for:

      • Embedded systems

      • Compact environmental sensing

    f-strong>40C to +125C

  • Humidity range: 0100% RH (non-condensing preferred)

  Maintains accuracy across wide environmental conditions.

  Operating Behavior

  Fast Response

  • Quick reaction to environmental changes

  Temperature Compensation

  • Internal compensation improves humidity accuracy

  Heater Usage

  • Can be activated periodically to:

    • Improve reliability in humid environments

    • Reduce sensor contamination

  Limitations

  • Measures relative humidity only

  • Sensitive to:

    • Condensation (without heater usage)

    • Chemical contamination

  • Requires proper airflow for best accuracy

  Bres:

  • Stable power routing

  • I2C interface access

• Uses 4-pin connector for easy integration