ISL29012IROZ-EVALZ Intersil, ISL29012IROZ-EVALZ Datasheet - Page 3

• Manufacturer Part Number: ISL29012IROZ-EVALZ
• Description: EVALUATION BOARD ISL29012IROZ
• Manufacturer: Intersil

Specifications of ISL29012IROZ-EVALZ

• Sensor Type: Light, Digital Output
• Sensing Range: 128000Lux
• Interface: I²C, SMBus
• Sensitivity: 540nm
• Voltage - Supply: 2.5 V ~ 3.3 V
• Embedded: No
• Utilized Ic / Part: ISL29012
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Pin Descriptions
Principles of Operation
Photodiodes
The ISL29012 contains two photodiode arrays which convert
light into current. One diode (D1) is sensitive to both visible
and infrared light, while the other one (D2) is only sensitive to
infrared light; see Figure 21. Using the infrared portion of the
light as a baseline, the visible light can be extracted. The
ambient light output is the difference between D1 and D2. The
resultant ALS spectral response vs wavelength is shown in
Figure 7 in the “Typical Performance Curves” on page 11.
After light is converted to current during the light data process,
the current output is converted to digital by a single built-in
integrating type signed 15-bit Analog-to-Digital Converter
(ADC). An I
counts.
The converter is a charge-balancing integrating type signed
15-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 Time or Conversion Time” on page 7 and “Noise
Rejection” on page 8.
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 dual speed
oscillator (f
the ADC. In External Timing Mode, integration time is
determined by the time between two consecutive I
Timing Mode commands. See “External Timing Mode” on
page 7. A good balancing act of integration time and resolution
depending on the application is required for optimal results.
The ADC has four I
dynamically accommodate various lighting conditions. For
very dim conditions, the ADC can be configured at its lowest
range. For very bright conditions, the ADC can be configured
at its highest range.
PIN NUMBER
1
2
3
4
5
6
OSC
2
C command reads the visible light intensity in
), and the n-bit (n = 4, 8, 12,16) counter inside
2
PIN NAME
C programmable range selects to
REXT
GND
VDD
SCL
SDA
INT
3
Positive supply; connect this pin to a regulated 2.5V to 3.3V supply.
Ground pin. The thermal pad is connected to the GND pin.
External resistor pin for ADC reference; connect this pin to ground through a (nominal) 100kΩ resistor with
1% tolerance.
Interrupt pin; LO for interrupt/alarming, open drain output.
I
I
2
2
C serial clock
C serial data
2
C External
ISL29012
The I
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
exceeds the upper threshold or goes below the lower
threshold. The user can also configure the persistency of the
interrupt pin. This helps to avoid 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) 8-bit registers available inside the ISL29012.
The command and control registers define the operation of the
device. The command and control registers do not change until
the registers are overwritten. There are two 8-bit registers that
set the high and low interrupt thresholds. There are four 8-bit
data Read Only registers. Two bytes for the sensor reading and
another two bytes for the timer counts. The data registers
contain the ADC's latest digital output, and the number of clock
cycles in the previous integration period.
The ISL29012’s I
internally as 1000100. When 1000100x with x as R or W is
sent after a 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. Figure 3 shows a sync_I
diagram sample for externally controlled integration time.
The I
either the master or the slave can drive the SDA (data) line.
Figure 2 shows a sample write. Every I
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
condition (SDA rising while SCL remains high).
For more information about the I
the Phillips
2
C Interface
2
C bus lines can be pulled above VDD, 5.5V max.
2
DESCRIPTION
C bus master always drives the SCL (clock) line, while
2
C transaction ends with the master asserting a stop
™
I
2
C specification documents.
2
C interface slave address is hardwired
2
C standard, please consult
2
C transaction begins
December 10, 2008
2
C timing
FN6476.1