MAX9635ESA+ Maxim Integrated Products, MAX9635ESA+ Datasheet - Page 12

• Manufacturer Part Number: MAX9635ESA+
• Description: Optical Sensors - Board Mount LOW-POW AMBIENT LIGHT SENSR W/ADC
• Manufacturer: Maxim Integrated Products

Specifications of MAX9635ESA+

• Supply Current: 0.65 uA
• Operating Supply Voltage: 1.7 V to 3.6 V
• Package / Case: uTDFN-6
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Industry’s Lowest-Power
Ambient Light Sensor with ADC
The count is multiplied by 0.045, which is the LSB.
Because of the logarithmic nature of autoranging cir-
cuitry implemented on the IC, resolution of ambient lux
readings scale with the absolute measurement. Table 8
lists the lux resolution and the lux ranges obtained from
the IC.
Interrupt is enabled by setting bit 0 of register 0x01 to
1 (see Table 1). INT, an open-drain output, pulls low
when an interrupt condition occurs (lux readings that
exceed threshold limits for a period greater than that set
by the Time register). The interrupt status bit is cleared
automatically if register 0x00 is read or if the interrupt is
disabled (INTE = 0).
The IC’s interrupt circuit requires the upper and lower
limit thresholds to be in a specific format to be properly
interpreted. The upper and lower limits, from registers
0x05 and 0x06 must match the lux high-byte format. This
consists of the 4 bits of the exponent and the 4 most sig-
nificant bits of the mantissa (E3 E2 E1 E0 M7 M6 M5 M4).
In this case, there is the following formula:
Lower lux threshold = (2
The exponent is a 4-bit number ranging from 0000 to
1110 (zero to 14).
Table 8. Lux per LSB in Automatic Mode
12
LUx (MIN)
11,796.5
23,593.0
47,185.9
94,371.8
1474.6
2949.1
5898.2
184.3
368.6
737.3
11.5
23.0
46.1
92.2
0
Threshold Register Data Format
(exponent)
LUx (MAx)
188,006.4
11,796.5
23,593.0
47,185.9
94,371.8
1474.6
2949.1
5898.2
184.3
368.6
737.3
11.5
23.0
46.1
92.2
Interrupt Settings
x mantissa) x 0.045
AUTOMATIC MODE
LUx PER LSB IN
184.32
368.64
737.28
0.045
11.52
23.04
46.08
92.16
0.09
0.18
0.36
0.72
1.44
2.88
5.76
The mantissa is an 8-bit number ranging from 0000 0000
to 1111 0000 (zero to 240).
Upper lux threshold = (2
The exponent is a 4-bit number ranging from 0000 to
1110 (zero to 14).
The mantissa is an 8-bit number ranging from 0000 1111
to 1111 1111 (15 to 255).
In the auto range mode (MANUAL = 0), the upper thresh-
old and lower threshold bytes must be in a format that
matches the format used in register 0x03, the lux high
byte. There are only two rules to follow:
• For very low lux levels (light levels below 11.5 lux),
• For all other conditions (light levels above 11.5 lux)
In manual mode (MANUAL = 1), Table 9 gives the range
of exponent (E3 E2 E1 E0) that can be used for each
TIM[2:0] and CDR bit setting.
set the exponent to zero, the code is merely: 0000
MMMM where the 4 zeroes are the exponent, and the
MMMM represent the 4 most significant bits of the
mantissa.
where the exponent is not zero, the format is: EEEE
1MMM. Notice that bit M7 (most significant bit) must
always be a 1. The other bits do not matter. EEEE is
limited to a maximum value of 1110. The maximum
usable setting is a code of 1110 1111.
COUNTS (MIN)
1,048,576
2,097,152
131,072
262,144
524,288
16,384
32,768
65,536
1024
2048
4096
8192
256
512
0
(exponent)
x mantissa) x 0.045
COUNTS (MAx)
1,048,576
2,097,152
4,177,920
131,072
262,144
524,288
16,384
32,768
65,536
1024
2048
4096
8192
256
512