ALS-PDIC17-79NB-TR8 Datasheet, PDF (11/21 Pages) Everlight Electronics Co., Ltd – I2 Digital Ambient Light Sensor

Surface - Mount
I²C Digital Ambient Light Sensor
ALS-PDIC17-79NB/TR8
Theory of Operation
The photocurrent, generated by the built-in photodiode while being illuminated, is proportionally
converted to frequency; the digital frequency signal is then integrated by a 15-bit counter for a predetermined
period of time (tint). This period of time is called integration time which can be adjusted by changing the
nominal value of the resistor between the RINT and GND terminals. The converted data are read out through
a two-wire, I2C Interface bus. Since the photodiode has been specially processed to suppress the spectral
response in infrared region, the readout is very close to the photopic transfer function, v(λ), which is the
mathematic expression of human-eye's response to ambient light.
Address Option for I²C
The I²C address is determined before placing an order; users can assign any one of the three
addresses (0x39, 0x29, 0x40) for their specific application. Without any prior request for a specific I2C address,
the default address is 0x39.
Table 1. Conncecting options of I²C address
Address Pin
Configuration
Floating
Tied to GND
Tied to VCC
I2C Address
0x39 (default)
0x29
0x44
ADC Register
The ADC register contains 16 bits with a 15-bit wide data from D0 to D14 and a valid bit D15. The
register is divided into two groups; D[15..8] is the most significant (MS) byte and D[7..0] is the least significant
(LS) byte. See Table 2 for details.
Table 2. ADC Register Structure
Valid Bit
Data Bits
D15
D14
D13 ~ D8
D7~D1
D0
MSB
LSB
Most Significant (MS) byte
Least Significant (LS) byte
Everlight Electronics Co., Ltd.
Document No: DLS-xxxxxxx Rev1
11
http://www.everlight.com
Oct. 12, 2010