OPT3006 Datasheet, PDF (11/41 Pages) Texas Instruments – OPT3006 Ultra-Thin Ambient Light Sensor

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OPT3006
SBOS698 – OCTOBER 2016
7.3 Feature Description
7.3.1 Human Eye Matching
The OPT3006 spectral response closely matches that of the human eye. If the ambient light sensor
measurement is used to help create a good human experience, or create optical conditions that are optimal for a
human, the sensor must measure the same spectrum of light that a human sees.
The device also has excellent infrared light (IR) rejection. This IR rejection is especially important because many
real-world lighting sources have significant infrared content that humans do not see. If the sensor measures
infrared light that the human eye does not see, then a true human experience is not accurately represented.
Furthermore, if the ambient light sensor is hidden underneath a dark window (such that the end-product user
cannot see the sensor) the infrared rejection of the OPT3006 becomes significantly more important because
many dark windows attenuate visible light but transmit infrared light. This attenuation of visible light and lack of
attenuation of IR light amplifies the ratio of the infrared light to visible light that illuminates the sensor. Results
can still be well matched to the human eye under this condition because of the high infrared rejection of the
OPT3006.
7.3.2 Automatic Full-Scale Range Setting
The OPT3006 has an automatic full-scale range setting feature that eliminates the need to predict and set the
optimal range for the device. In this mode, the OPT3006 automatically selects the optimal full-scale range for the
given lighting condition. The OPT3006 has a high degree of result matching between the full-scale range
settings. This matching eliminates the problem of varying results or the need for range-specific, user-calibrated
gain factors when different full-scale ranges are chosen. For further details, see the Automatic Full-Scale Setting
Mode section.
7.3.3 Interrupt Operation, INT Pin, and Interrupt Reporting Mechanisms
The device has an interrupt reporting system that allows the processor connected to the I²C bus to go to sleep,
or otherwise ignore the device results, until a user-defined event occurs that requires possible action.
Alternatively, this same mechanism can also be used with any system that can take advantage of a single digital
signal that indicates whether the light is above or below levels of interest.
The interrupt event conditions are controlled by the high-limit and low-limit registers, as well as the configuration
register latch and fault count fields. The results of comparing the result register with the high-limit register and
low-limit register are referred to as fault events. The fault count register dictates how many consecutive same-
result fault events are required to trigger an interrupt event and subsequently change the state of the interrupt
reporting mechanisms, which are the INT pin, the flag high field, and the flag low field. The latch field allows a
choice between a latched window-style comparison and a transparent hysteresis-style comparison.
The INT pin has an open-drain output, which requires the use of a pull-up resistor. This open-drain output allows
multiple devices with open-drain INT pins to be connected to the same line, thus creating a logical NOR or AND
function between the devices. The polarity of the INT pin can be controlled with the polarity of interrupt field in
the configuration register. When the POL field is set to 0, the pin operates in an active low behavior that pulls the
pin low when the INT pin becomes active. When the POL field is set to 1, the pin operates in an active high
behavior and becomes high impedance, thus allowing the pin to go high when the INT pin becomes active.
Additional details of the interrupt reporting registers are described in the Interrupt Reporting Mechanism Modes
and Internal Registers sections.
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