ISL29015IROZ-EVALZ Intersil, ISL29015IROZ-EVALZ Datasheet - Page 7

• Manufacturer Part Number: ISL29015IROZ-EVALZ
• Description: EVALUATION BOARD FOR ISL29015
• Manufacturer: Intersil

Specifications of ISL29015IROZ-EVALZ

• Sensor Type: Light, Digital Output
• Sensing Range: 65535Lux
• Interface: I²C, SMBus
• Sensitivity: 540nm
• Voltage - Supply: 2.25 V ~ 3.3 V
• Embedded: No
• Utilized Ic / Part: ISL29015
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

.
Data Registers (02 hex and 03 hex)
The device has two 8-bit read-only registers to hold the data
from LSB to MSB for ADC. The most significant bit (MSB) is
accessed at 03 hex, and the least significant bit (LSB) is
accessed at 02 hex. For 16-bit resolution, the data is from
D0 to D15; for 12-bit resolution, the data is from D0 to D11;
for 8-bit resolution, the data is from D0 to D7. The registers
are refreshed after every conversion cycle.
Calculating Lux
The ISL29015’s ADC output codes, DATA, are directly
proportional to lux in the ambient light sensing.
Here, E
determined by the Full Scale Range and the ADC’s
maximum output counts. The constant is independent on the
light sources (fluorescent, incandescent and sunlight)
because of the light sources’ IR component is removed
during the light signal process. The constant can also be
viewed as the sensitivity: the smallest lux measurement the
device can measure is shown in Equation 2.
α
E
4. Range: Bits 1 and 0. The Full Scale Range (FSR) can be
ADDRESS
cal
BITS
=
1:0
00
01
10
11
BITS 3:2
(A/D) converter samples the photodiode current signal for
a measurement.
adjusted via I
possible values of FSR for the 499kΩ R
(hex)
----------------------------
Count
Range k ( )
02
03
=
00
01
10
11
α
cal
1
2
3
4
×
k
max
DATA
is the calculated lux reading. The constant α is
D0 is LSB for 4, 8, 12 or 16-bit resolution, D3 is MSB
for 4-bit resolution, D7 is MSB for 8-bit resolution
D15 is MSB for 16-bit resolution, D11 is MSB for
12-bit resolution
RANGE(k)
TABLE 5. RESOLUTION/WIDTH
2
2
2
2
Range1
Range2
Range3
Range4
NUMBER OF CLOCK CYCLES
TABLE 7. DATA REGISTERS
16
12
8
4
TABLE 6. RANGE/FSR LUX
2
= 256
= 16
C using Bits 1 and 0. Table 6 lists the
= 65,536
= 4,096
ALS SENSING
FSR (LUX) @
7
CONTENTS
16,000
64,000
1,000
4,000
EXT
Refer to page 3
Refer to page 3
Refer to page 3
Refer to page 3
FSR @ IR
SENSING
n-BIT ADC
resistor.
16
12
8
4
(EQ. 1)
(EQ. 2)
ISL29015
Here, Range(k) is defined in Table 6. Count
maximum output counts from the ADC.
The transfer function used for n-bit ADC becomes:
Here, n = 4, 8, 12 or 16. This is the number of ADC bits
programmed in the command register. 2
maximum number of counts possible from the ADC output.
Data is the ADC output stored in the data registers (02 hex
and 03 hex).
Integration and Conversion Time
The ADC resolution and f
time, t
t
where n is the number of bits of resolution and n = 4, 8, 12 or
16. 2
programmed at the command register 01(hex) bits 3 and 2.
External Scaling Resistor R
Range
The ISL29015 uses an external resistor R
internal oscillator frequency, f
range. f
For user simplicity, the proportionality constant is referenced
to 499kΩ:
Noise Rejection
In general, integrating type ADC’s have excellent
noise-rejection characteristics for periodic noise sources whose
frequency is an integer multiple of the conversion rate. For
instance, a 60Hz AC unwanted signal’s sum from 0ms to
k*16.66ms (k = 1,2...k
integration time to be an integer multiple of the periodic noise
signal, greatly improves the light sensor output signal in the
presence of noise.
ADC Output in IR Sensing
The ISL29015’s ADC output codes, DATA, are directly
proportional to the IR intensity received in the IR sensing
phase.
E
Range
f
int
**Recommended R
OSC
cal
R
499**
(kΩ)
250
EXT
=
=
n
2
=
int
, therefore, is the number of clock cycles. n can be
n
Range k ( )
---------------------------
OSC
=
499kΩ
----------------- -
.
×
R
TABLE 8. INTEGRATION TIME OF n-BIT ADC
499kΩ
----------------- -
------------- -
f
EXT
R
n = 16-BIT
2
OSC
n
1
EXT
and Range are inversely proportional to R
45ms
90ms
×
=
725
×
×
EXT
2
Range k ( )
DATA
n
kHz
×
i
) is zero. Similarly, setting the device’s
resistor value
--------------------------------------------- -
725kHz
n = 12-BIT
2.812ms
5.63ms
OSC
R
EXT
OSC
×
determines the integration
499kΩ
EXT
and the light sensing
n = 8-BIT
175.5µs
for f
351µs
n
EXT
represents the
OSC
max
to fix its
is the
and
October 31, 2008
n = 4-BIT
10.8µs
21.6µs
(EQ. 3)
FN6522.0
(EQ. 5)
(EQ. 6)
(EQ. 4)
EXT
.