ISL29001IROZ Intersil, ISL29001IROZ Datasheet - Page 7

• Manufacturer Part Number: ISL29001IROZ
• Description: IC SENSOR LIGHT-DGTL I2C 6-ODFN
• Manufacturer: Intersil
• Series: -r

Specifications of ISL29001IROZ

• Wavelength: 540nm
• Output Type: I²C™
• Package / Case: 6-WDFN Exposed Pad
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Data Registers
The ISL29001 contains four 8-bit data registers. These
registers cannot be specifically addressed, as is conventional
with other I
on the device always returns all available registers in ascending
order. See Table 2 for a description of each register.
The first two 8-bit data registers contain the most recent
sensor reading. The meaning of the specific value stored in
these data registers depends on the command written via
the I
commands. The first byte read over the I
least-significant byte; the second is the most significant. This
byte ordering is often called “little-endian” ordering.
The third and fourth 8-bit data registers contain the
integration counter value corresponding to the most recent
sensor reading. The ISL29001 includes a free-running
oscillator, each cycle of which increments a 16-bit counter. At
the end of each integration period, the value of this counter
is made available in these two 8-bit registers. Like the
sensor reading, the integration counter value is read across
the I
Note that the integration counter value is only available
when using one of the three externally-timed operating
modes; when using internally-timed modes, the device will
NAK after the two-byte sensor reading has been read.
Internal Timing
When using one of the three internal timing modes, each
integration period of the ISL29001 is timed by 32,768 clock
cycles of an internal oscillator. The nominal frequency of the
internal oscillator is 327.6kHz, which provides 100ms
internally-timed integration periods. The oscillator frequency
is dependent upon an external resistor, R
adjusted by selecting a different resistor value. The
resolution and maximum range of the device are also
affected by changes in R
The oscillator frequency can be calculated using Equation 1:
Accordingly, the integration time, t
as shown in Equation 2.
The full scale range in lux, FSR, is also scaled by R
f
ADDRESS
osc
00H
01H
02H
03H
2
2
=
C interface; see Table 1 for information on the various
C bus in little-endian order.
327.6kHz
2
C peripherals; instead, performing a read operation
Least-significant byte of most recent sensor reading.
Most-significant byte of most recent sensor reading.
Least-significant byte of integration counter value
corresponding to most recent sensor reading.
Most-significant byte of integration counter value
corresponding to most recent sensor reading.
TABLE 2. DATA REGISTERS
⋅
100kΩ
----------------- -
R
EXT
EXT
.
7
CONTENTS
int
, is also a function of R
2
EXT
C interface is the
, and can be
EXT.
(EQ. 1)
EXT,
ISL29001
R
timing and a 1 to 10,000lux range for Diode 1. Doubling this
resistor value to 200kΩ halves the internal oscillator
frequency, providing 200ms internal timing. In addition, the
maximum lux range of Diode 1 is also halved, from
10,000 lux to 5,000 lux, and the resolution is doubled, from
3.3 counts per lux to 6.6 counts per lux.
The acceptable range of this resistor is 50kΩ (providing
50ms internal timing, 20,000 lux maximum reading, ~1.6
counts per lux) to 500kΩ (500ms internal timing, 2,000lux
maximum reading, ~16 counts per lux).
When using one of the three internal timing modes, the
ISL29001’s resolution is determined by the ratio of the max
lux range to 32,768, the number of clock cycles per
integration.
Equation 4 describes the light intensity as a function of the
sensor reading, and as a function of the external resistor.
where E is the measured light intensity, Data1 is the sensor
reading, and R
External Timing
When using one of the three external timing modes, each
integration period of the ISL29001 is determined by the time
which passes between consecutive external timing
commands received over the I
integration by sending an external command and stops the
integration by sending another external command. The
integration time, t
where:
E Lux
t
FSR
t
Recommended
E Lux
int
int
i
f
EXT
(
I2C
I2C
(
500 (Max)
50 (Min)
=
=
R
(kΩ)
=
is the number of I
is the I
100
200
)
is nominally 100kΩ, and provides 100ms internal
i
----------
f
100ms
EXT
)
I2C
I2C
=
10000lux
TABLE 3. R
=
--------------- -
32768
--------------- -
32768
FSR
1
2
⋅
C operating frequency.
----------------- -
100kΩ
EXT
R
⋅
INTEGRATION
⋅
EXT
------------------------------------------ - Data1
(
⋅
Data1
R
int
100kΩ
----------------- -
R
10 000lux
EXT
EXT
is external resistor value.
, therefore is determined by Equation 5:
EXT
TIME
(ms)
,
100
200
500
50
⁄
RESISTOR SELECTION GUIDE
2
100kΩ
C clock cycles to obtain the t
)
2
⋅
C bus. The user starts the
LUX RANGE
20,000
10,000
5,000
2,000
(lux)
RESOLUTION,
COUNTS/LUX
December 10, 2008
1.6
16
3
6
int.
FN6166.6
(EQ. 5)
(EQ. 3)
(EQ. 4)
(EQ. 2)