Datasheet
Industry’s Lowest-Power
Ambient Light Sensor with ADC
Table 9. Recommended Manual Mode Settings for Configuration Register (0x02) and
Threshold Registers (0x05, 0x06)
Note: In manual mode, exceeding the lux (max) causes an overload error (exponent = 1111).
Typical Operating Sequence
To utilize the ultra-low power consumption of the IC in
end applications, an interrupt pin is provided to eliminate
the need for the system to poll the device continuously.
Since every clock and data bit transmitted on I
2
C can
consume up to 1mA (assuming 1.8kI pullup resistor to
a 1.8V rail), minimizing the number of I
2
C transactions
on the data bus can save a lot of power. In addition,
eliminating the need to poll the device frees up process-
ing resources for the master, improving overall system
performance.
The typical sequence of communication with the IC is
as follows:
1) Master reads lux reading from registers 0x03 and
0x04.
2) Master sets the upper lux threshold and lower lux
threshold in registers 0x05 and 0x06 so that a user-
programmed window is defined around the current
lux readings.
3) Master sets suitable threshold timer data in register
0x07.
4) Master works on other tasks until alerted by the INT
pin going low. This is where the master spends much
of its time.
5) When alerted by the INT pin going low, the master
reads the Interrupt Status register 0x00 to confirm
the source of interrupt was the IC. The master takes
appropriate action.
6) Repeat from Step 1.
APPLICATION CONDITIONS
RECOMMENDED SETTINGS
FOR CONFIGURATION
REGISTER (0x03)
RANGE OF EXPONENTS FOR
UPPER AND LOWER REGISTERS
(0x05 AND 0x06)
LUX LSB
(MIN)
LUX
(MAX)
LUX LSB
(MAX)
INTEGRATION
TIME (ms)
TIM CDR
EXPONENT
(MIN)
EXPONENT
(MAX)
0.045 2938 11.52 800 000 0 0000 1000
0.09 5875 23.04 400 001 0 0001 1001
0.18 11,750 46.08 200 010 0 0010 1010
0.36 23,501 92.16
100 011 0
0011 1011
800 000 1
0.72 47,002 184.32
50 100 0
0100 1100
400 001 1
1.44 94,003 368.64
25 101 0
0101 1101
200 010 1
2.88 188,006 737.28
12.5 110 0
0110 1110
100 011 1
5.76 188,006 737.28
6.25 111 0
0111 1110
50 100 1
11.52 188,006 737.28 25 101 1 1000 1110
23.04 188,006 737.28 12.5 110 1 1001 1110
46.08 188,006 737.28 6.25 111 1 1010 1110
Maxim Integrated
13
MAX44009