ISL29023IROZ-T7 Intersil, ISL29023IROZ-T7 Datasheet - Page 4

• Manufacturer Part Number: ISL29023IROZ-T7
• Description: IC SENSOR LIGHT-DGTL I2C 6ODFN
• Manufacturer: Intersil

Specifications of ISL29023IROZ-T7

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Principles of Operation
Photodiodes and ADC
The ISL29023 contains two photodiode arrays which convert
light into current. The spectral response for ambient light
sensing and IR sensing is shown in Figure 5 in the performance
curves section. After light is converted to current during the light
signal process, the current output is converted to digital by a
built-in 16-bit Analog-to-Digital Converter (ADC). An I
command reads the ambient light or IR intensity in counts.
The converter is a charge-balancing integrating type 16-bit
ADC. The chosen method for conversion is best for converting
small current signals in the presence of an AC periodic noise. A
100ms integration time, for instance, highly rejects 50Hz and
60Hz power line noise simultaneously. See “Integration and
Conversion Time” on page 7.
The built-in ADC offers user flexibility in integration time or
conversion time. There are two timing modes: Internal Timing
Mode and External Timing Mode. In Internal Timing Mode,
integration time is determined by an internal oscillator (f
and the n-bit (n = 4, 8, 12, 16) counter inside the ADC. In
External Timing Mode, integration time is determined by the
time between two consecutive I
commands. A good balancing act of integration time and
resolution (depending on the application) is required for optimal
results.
The ADC has I
accommodate various lighting conditions. For very dim
conditions, the ADC can be configured at its lowest range
(Range 1) in the ambient light sensing.
Low-Power Operation
The ISL29023 initial operation is at the power-down mode
after a supply voltage is provided. The data registers contain
the default value of 0. When the ISL29023 receives an I
command to do a one-time measurement from an I
master, it will start ADC conversion with light sensing. It will
go to the power-down mode automatically after one
conversion is finished and keep the conversion data
available for the master to fetch anytime afterwards. The
ISL29023 will continuously do ADC conversion with light
sensing if it receives an I
measurement. It will continuously update the data registers
with the latest conversion data. It will go to the power-down
mode after it receives the I
Ambient Light and IR Sensing
There are four operational modes in ISL29023: Programmable
ALS once with auto power-down, programmable IR sensing
once with auto power-down, programmable continuous ALS
sensing and programmable continuous IR sensing. These four
modes can be programmed in series to fulfill the application
needs. The detailed program configuration is listed in
“Command Register I 00(hex)” on page 5.
2
C programmable range select to dynamically
2
C command of continuous
2
C command of power-down.
4
2
C External Timing Mode
2
2
C
C
OSC
2
C
),
ISL29023
When the part is programmed for ambient light sensing, the
ambient light with wavelength within the “Ambient Light
Sensing” spectral response curve in Figure 5 is converted
into current. With ADC, the current is converted to an
unsigned n-bit (up to 16 bits) digital output.
When the part is programmed for infrared (IR) sensing, the
IR light with wavelength within the “IR Sensing” spectral
response curve in Figure 5 is converted into current. With
ADC, the current is converted to an unsigned n-bit (up to
16-bits) digital output.
Interrupt Function
The active low interrupt pin is an open drain pull-down
configuration. The interrupt pin serves as an alarm or
monitoring function to determine whether the ambient light
level exceeds the upper threshold or goes below the lower
threshold. It should be noted that the function of ADC
conversion continues without stopping after interrupt is
asserted. If the user needs to read the ADC count that
triggers the interrupt, the reading should be done before the
data registers are refreshed by the following conversions.
The user can also configure the persistency of the interrupt
pin. This reduces the possibility of false triggers, such as
noise or sudden spikes in ambient light conditions. An
unexpected camera flash, for example, can be ignored by
setting the persistency to 8 integration cycles.
I
There are eight 8-bit registers available inside the ISL29023.
The two command registers define the operation of the
device. The command registers do not change until the
registers are overwritten. The two 8-bit data Read Only
registers are for the ADC output. The data registers contain
the ADC's latest digital output, or the number of clock cycles
in the previous integration period.
The ISL29023’s I
wired as 1000100. When 1000100x with x as R or W is sent
after the Start condition, this device compares the first 7 bits of
this byte to its address and matches.
Figure 1 shows a sample one-byte read. Figure 2 shows a
sample one-byte write. The I
SCL (clock) line, while either the master or the slave can drive
the SDA (data) line. Figure 2 shows a sample write. Every I
transaction begins with the master asserting a start condition
(SDA falling while SCL remains high). The following byte is
driven by the master, and includes the slave address and
read/write bit. The receiving device is responsible for pulling
SDA low during the acknowledgement period. Every I
transaction ends with the master asserting a stop condition
(SDA rising while SCL remains high).
For more information about the I
the Philips
2
C Interface
™
I
2
C specification documents.
2
C interface slave address is internally hard-
2
C bus master always drives the
2
C standard, please consult
March 3, 2009
2
C
FN6691.0
2
C