Sensirion SGP40 & SGP41: Reliable VOC and NOx Monitoring
Discover Sensirion's advanced metal-oxide (MOX) gas sensors for indoor air quality monitoring.
Metal Oxide Gas Sensors
Sensirion's CMOSens® sensor technology integrates metal-oxide (MOX) sensors onto a single chip. These sensors operate by heating the metal oxide surface, causing its electrical resistance to change. Oxidizing gases (like NOx) increase resistance, while reducing gases (like VOCs) decrease resistance.
VOC Index Algorithm
The VOC Index algorithm provides reliable monitoring of indoor VOC levels. It processes raw signals from SGP4x sensors via a microcontroller to generate an index reflecting current VOC levels relative to the sensor's average VOC environment. This index can be used to dynamically control air treatment device fan speeds or inform users about daily activities affecting air quality.
Evaluation Kit SEK-SVM4x
The SEK-SVM4x evaluation kit offers a cost-effective and simple way to evaluate Sensirion's SGP40 (VOC sensor) and SGP41 (VOC + NOx sensor). It features plug-and-play hardware and the 'ControlCenter' viewer software, enabling quick and efficient sensor performance assessment. The kit includes:
- SVM4x sensor module (SGP41, SHT40, microcontroller)
- UART-USB adapter cable
- 6-pin jumper wire cable
The ControlCenter software allows viewing and logging signals from multiple sensors on a single PC, outputting VOC + NOx index values, relative humidity, and temperature.
SGP40: Digital VOC Sensor
The SGP40 is a digital VOC sensor designed for easy integration into air treatment devices and air quality monitors. It features a digital I²C interface, a temperature-controlled micro hot-plate, and humidity compensation for accurate indoor air quality signal processing. Combined with the VOC Index algorithm, it enables direct indoor air quality assessment.
Key Features:
- Siloxane resistance (MOXSens® technology) with a 10-year lifetime
- VOC Index circuitry
- On-chip humidity compensation
- Low self-heating
- Compact footprint: 2.44 x 2.44 x 0.85 mm³
- High sensitivity to most VOCs
- Wide supply voltage range: 1.7 – 3.6 V
- Digital I²C interface
Benefits:
- Reliable sensor hardware
- No signal processing programming required
- High performance across various environments
- Improved RH/T measurement accuracy
- Space-efficient design-in
- Wide-range sensor for general VOCs
- Suitable for a broad range of applications
- Simple design-in and interface
Applications:
- Air purifiers
- Indoor air quality monitors
- Kitchen hoods
- Smart home devices
- Thermostats
- Demand-controlled ventilation
SGP41: Digital VOC & NOx Sensor
The SGP41 is a high-performance digital smart switch and actuator sensor for air treatment devices and air quality monitors. It integrates two sensor types on a single chip, simplifying design-in and reducing costs. Using the gas index algorithm, it processes signals from both sensors to automatically initiate gas pollutant removal.
Key Features:
- Dual sensor on a single chip
- Siloxane resistance (MOXSens® technology) with a 10-year lifetime
- Gas Index circuitry
- On-chip humidity compensation
- Low self-heating
- Compact footprint: 2.44 x 2.44 x 0.85 mm³
- High sensitivity to most VOCs
- Wide supply voltage range: 1.7 – 3.6 V
- Digital I²C interface
Benefits:
- Cost reduction and simplified design-in
- Reliable sensor hardware
- No signal processing programming required
- High performance across various environments
- Improved RH/T measurement accuracy
- Space-efficient design-in
- Wide-range sensor for general VOCs
- Suitable for a broad range of applications
- Simple design-in and interface
Applications:
- Air purifiers
- Indoor air quality monitors
- Kitchen hoods
- Smart home devices
- Thermostats
- Demand-controlled ventilation
Specifications
Gas Sensing Specifications
| Feature | VOC | NOx |
|---|---|---|
| Target Products | SGP40, SGP41 | SGP41 |
| Algorithm Output | 1–500 VOC Index Value¹ | 1–500 NOx Index Value¹ |
| Sensor Output | 16-bit resolution² | |
| Measurement Range | 0–1,000,000 ppb (ethanol equivalent) | 0–10,000 ppm (NO₂) |
| Device Variation | < ±15 VOC Index Value or 15% m.v. (whichever is greater) | < ±50 NOx Index Value or 50% m.v. (whichever is greater) |
| Detection Limit | < 50 ppb (ethanol equivalent) or < 10% (setpoint) (whichever is greater) | < 20 ppb (NO₂) or < 10% (setpoint) (whichever is greater) |
| Response Time (T63%) | < 10 s | < 250 s |
| Switch-on Time | < 60 s | |
Electrical Specifications
| Feature | Value |
|---|---|
| Supply Voltage Range (V) | 1.7 – 3.6 |
| Idle Current (µA) | 34 |
| Current Consumption (mA) | 1.8 V operating: 3.5 (VOC), 3.0 (NOx) 3.3 V operating: 2.6 (VOC), 3.0 (NOx) |
| Interface | I²C |
| Size | 2.44 x 2.44 x 0.85 mm³ |
| IAQ Standard Compliance | RESET, WELL |
¹ Sensirion's gas index algorithm processes raw signals externally to provide ready-to-use air quality signals.
² Raw signals are proportional to the logarithm of the MOX resistance.
