ISL29010IROZ-T7 Intersil, ISL29010IROZ-T7 Datasheet - Page 7

• Manufacturer Part Number: ISL29010IROZ-T7
• Description: IC SENSOR LIGHT-DGTL I2C 6-ODFN
• Manufacturer: Intersil

Specifications of ISL29010IROZ-T7

• Wavelength: 540nm
• Output Type: I²C™
• Package / Case: 6-ODFN
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ISL29010IROZ-T7TR

Number of Clock Cycles, n-bit ADC
The number of clock cycles determines “n” in the n-bit ADC; 2
clock cycles is a n-bit ADC. n is programmable in the command
register in the width function. Depending on the application, a
good balance of speed and resolution has to be considered
when deciding for n. For fast and quick measurement, choose
the smallest n = 3. For maximum resolution without regard of
time, choose n = 15. Table 10 compares the trade-off between
integration time and resolution. See Equations 10 and 11 for the
relation between integration time and n. See Equation 3 for the
relation of n and resolution.
External Scaling Resistor R
The ISL29010 uses an external resistor R
internal oscillator frequency, f
determines the f
device. f
proportional to R
constant is referenced to fixed constants 100kΩ and
655kHz:
f
When the Range/Gain bits are set to Range1 or Range2,
f
are set to Range3 and Range4.
f
The automatic f
improvement of signal-to-noise ratio when detecting very low
lux signals.
f
R
OSC
OSC
OSC
OSC
TABLE 10. RESOLUTION AND INTEGRATION TIME
EXT
f
set. This is nominally 327kHz when R
f
are set. This is nominally 655kHz when R
OSC
OSC
15
11
n
7
3
1
1
2
runs at half speed compared to when Range/Gain bits
= 100kΩ
=
=
=
1 is oscillator frequency when Range1 or Range2 are
2 is the oscillator frequency when Range3 or Range4
OSC
1
-- -
2
1
-- - f
2
100kΩ
----------------- -
R
(
×
EXT
OSC
SELECTION
(ms)
100kΩ
----------------- -
12.8
0.05
t
200
, a dual speed mode oscillator, is inversely
R
0.8
INT
EXT
f
OSC
OSC
OSC
×
2
EXT
)
655
RANGE1
×
. For user simplicity, the proportionality
= 327kHz
, integration time and the FSR of the
adjustment feature allows significant
655
RESOLUTION
kHz
LUX/COUNT
kHz
0.06
15.6
250
1.0
OSC
7
EXT
. Consequently, R
0.025
(ms)
and f
t
100
6.4
0.4
INT
EXT
f
OSC
EXT
RANGE4
EXT
osc
is 100kΩ.
= 655kHz
RESOLUTION
(LUX/COUNT)
to fix its
is 100kΩ.
16,000
1,000
62.5
EXT
2
(EQ. 7)
(EQ. 6)
(EQ. 8)
ISL29010
n
Integration Time or Conversion Time
Integration time is the period during which the device’s
analog-to-digital ADC converter samples the photodiode
current signal for a lux measurement. Integration time, in
other words, is the time to complete the conversion of analog
photodiode current into a digital signal (number of counts).
Integration time affects the measurement resolution. For
better resolution, use a longer integration time. For short and
fast conversions use a shorter integration time.
The ISL29010 offers user flexibility in the integration time to
balance resolution, speed and noise rejection. Integration time
can be set internally or externally and can be programmed in
the command register 00(hex) Bit 5.
INTEGRATION TIME IN INTERNAL TIMING MODE
This timing mode is programmed in the command register
00(hex) Bit 5. Most applications will be using this timing
mode. When using the Internal Timing Mode, f
n-bits resolution determine the integration time. t
function of the number of clock cycles and f
t
Since f
t
is shown in Equation 10:
t
t
INT
INT
INT
*Integration time in milliseconds
**Recommended R
INT
TABLE 11. INTEGRATION TIMES FOR TYPICAL R
m = 4, 8, 12, and16. n is the number of bits of resolution.
2
programmed at the command register 00(hex) Bits 1 and 0.
t
for Internal Timing Mode and Gain/Range is set to Range1
or Range2.
t
for Internal Timing Mode and Gain/Range is set to Range3
or Range4.
INT
INT
R
100**
(kΩ)
m
1
200
500
2
50
EXT
is dual time. The integration time as a function of R
=
therefore is the number of clock cycles. n can be
=
1 is the integration time when the device is configured
=
2 is the integration time when the device is configured
2
OSC
m
2
2
m
m
×
×
----------
f
×
is dual speed depending on the Gain/Range bit,
osc
n = 15-BIT
1
--------------------------------------------- -
327kHz
--------------------------------------------- -
655kHz
1000
100
200
400
EXT
R
R
for Internal Timing Mode only
RANGE1
RANGE2
EXT
EXT
×
×
resistor value
100kΩ
100kΩ
n = 11-BIT
6.4
13
26
64
n = 11-BIT
3.2
6.5
13
32
OSC
RANGE3
RANGE4
OSC
February 13, 2008
.
EXT
INT
and
is a
VALUES
0.013
0.025
0.050
0.125
n = 3
(EQ. 11)
(EQ. 10)
FN6414.0
(EQ. 9)
EXT