The AS7331 is a low-power, low noise integrated UV sensor. The three separated UVA, UVB and UVC channels convert optical radiation signals via UV optimized photodiodes to a digital result and realize a continuous or triggered measurement. The irradiance responsivity can be adjusted via Gain, conversion time and internal clock frequency to effect sensitivity, full scale range and LSB. The by the AS7331 detected amount of radiation in the set Gain and conversion time configuration will be provided as digital counts by the AS7331. The AS7331 offers a range of 12 Gain steps by a factor of two for each step. The conversion time is internally controlled over a wide range of 15 steps by a factor of two for each step. With the input pin (SYN), the conversion time can be externally controlled to adapt the measurement to the given environment and time base.
With its irradiance responsivity factor and conversion time, the AS7331 supports an overall huge dynamic range up to 3.43E+10 (resolution multiplied by gain range). It achieves an accuracy of up to 24-bit signal resolution (internal via I²C and shifter 16-bit), with an irradiance responsivity per count down to 2.38 nW/cm² at 64 ms integration time. Via an integrated divider, the 16-bit I²C output can be adjusted to the significant bits of interest.
The AS7331 Evluation Kit enables initial sensor measurements with the AS7331 spectral UV-sensor. The AS7331 EVK hardware is split in two parts, the sensorboard with an I2C interface and a communication board with USB output where the sensorboard is connected to. Additional to this the EVK provides a comfortable GUI which enables the access to all sensor settings. Furthermore measurements can be recorded and exported via csv file for further analysises. Also a source development kit (SDK) is included in the EVK. This SDK provides prepared libraries and sample codes to support comfortable firmware design-ins.