ISL29003 Datasheet

ISL29003
Data Sheet
Light-to-Digital Output Sensor with High
Sensitivity, Gain Selection, Interrupt
Function and I2C Interface
The ISL29003 is an integrated light sensors with a 16-bit
integrating type ADC, I2C user programmable lux range
select for optimized counts/lux, and I2C multi-function control
and monitoring capabilities. The internal ADC provides 16-bit
resolution while rejecting 50Hz and 60Hz flicker caused by
artificial light sources.
November 17, 2011
FN7464.6
Features
• Range select via I2C
- Range 1 = 0 lux to 1000 lux
- Range 2 = 0 lux to 4000 lux
- Range 3 = 0 lux to 16,000 lux
- Range 4 = 0 lux to 64,000 lux
• Human eye response (540nm peak sensitivity)
• Temperature compensated
In normal operation, power consumption is less than 300µA.
Furthermore, an available software power-down mode
controlled via the I2C interface reduces power consumption
to less than 1µA.
• 16-bit resolution
The ISL29003 supports a hardware interrupt that remains
asserted low until the host clears it through I2C interface.
• Simple output code, directly proportional to lux
Designed to operate on supplies from 2.5V to 3.3V, the
ISL29003 is specified for operation over the -40°C to +85°C
ambient temperature range.
• 50Hz/60Hz rejection
• User-programmable upper and lower threshold interrupt
• IR + UV rejection
• 2.5V to 3.3V supply
• 6 Ld ODFN (2.1mmx2mm)
Ordering Information
PART NUMBER
(Notes 1, 2, 3)
• Adjustable resolution: up to 65 counts per lux
• Pb-free (RoHS compliant)
PACKAGE
(Pb-free)
PKG. DWG. #
ISL29003IROZ (Note 4)
6 Ld ODFN
L6.2x2.1
ISL29003IROZ-T7
6 Ld ODFN
L6.2x2.1
ISL29003IROZ-EVAL
Evaluation Board
Applications
• Ambient light sensing
• Backlight control
NOTES:
• Temperature control systems
• Camera light meters
• Lighting controls
Block Diagram
VDD
1
PHOTODIODE 1
MUX
Pinout
ISL29003
(6 LD ODFN)
TOP VIEW
SHDN
4. Not recommended for new designs.
INT TIME
3. For Moisture Sensitivity Level (MSL), please see device
information page for ISL29003. For more information on MSL
please see tech brief TB466.
• Contrast control
GAIN/RANGE
2. These Intersil Pb-free plastic packaged products employ special
Pb-free material sets; molding compounds/die attach materials
and 100% matte tin plate - e3 termination finish, which is RoHS
compliant and compatible with both SnPb and Pb-free soldering
operations. Intersil Pb-free products are MSL classified at
Pb-free peak reflow temperatures that meet or exceed the
Pb-free requirements of IPC/JEDEC J STD-020.
MODE
1. Please refer to TB347 for details on reel specifications.
INTEGRATING
ADC
IREF
SCL
6
SDA
INTERRUPT
4 INT
COUNTER
5 SCL
4 INT
REXT 3
5
INT
216
THERMAL
PAD
I2C
EXT
TIMING
FOSC
GND 2
DATA
REGISTER
PHOTODIODE 2
6 SDA
VDD 1
COMMAND
REGISTER
3
2
REXT
GND
ISL29003
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC 2006-2008, 2011. All Rights Reserved
I2C Bus is a registered trademark owned by NXP Semiconductors Netherlands, B.V
Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.
ISL29003
Absolute Maximum Ratings (TA = +25°C)
Thermal Information
VDD Supply Voltage between VDD and GND . . . . . . . . . . . . . 3.6V
I2C Bus Pin Voltage (SCL, SDA) . . . . . . . . . . . . . . . . . -0.2V to 5.5V
I2C Bus Pin Current (SCL, SDA) . . . . . . . . . . . . . . . . . . . . . . <10mA
INT, REXT Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . . -0.2V to VDD
ESD Rating
Human Body Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2kV
Thermal Resistance (Typical, Note 5)
θJA (°C/W)
6 Ld ODFN Package . . . . . . . . . . . . . . . . . . . . . . . .
88
Maximum Die Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . +90°C
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +100°C
Operating Temperature . . . . . . . . . . . . . . . . . . . . . . .-40°C to +85°C
Pb-free reflow profile . . . . . . . . . . . . . . . . . . . . . . . . . .see link below
http://www.intersil.com/pbfree/Pb-FreeReflow.asp
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product reliability and
result in failures not covered by warranty.
NOTE:
5. θJA is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See
Tech Brief TB379.
IMPORTANT NOTE: All parameters having Min/Max specifications are guaranteed. Typical values are for information purposes only. Unless otherwise noted, all tests
are at the specified temperature and are pulsed tests, therefore: TJ = TC = TA
Electrical Specifications
PARAMETER
VDD = 3V, TA = +25°C, REXT = 100kΩ 1% tolerance, unless otherwise specified, Internal Timing Mode
operation (See “Principles of Operation” on page 3).
DESCRIPTION
CONDITION
MIN
(Note 8)
MAX
(Note 8)
UNIT
3.3
V
0.29
0.33
mA
0.1
1
µA
TYP
VDD
Power Supply Range
2.25
IDD
Supply Current
IDD1
Supply Current Disabled
Software disabled
fOSC1
Internal Oscillator Frequency
Gain/Range = 1 or 2
290
327
360
kHz
fOSC2
Internal Oscillator Frequency
Gain/Range = 3 or 4
580
655
720
kHz
FI2C
I2C Clock Rate
400
kHz
DATA0
Diode1 Dark ADC Code
5
Counts
DATA1
Full Scale ADC Code
65535
Counts
DATA2
Diode1 ADC Code Gain/Range = 1 Accuracy Mode1
24440
Counts
DATA3
Diode2 ADC Code Gain/Range = 1 Accuracy Mode2
DATA4
Diode1 ADC Code Gain/Range = 2 Accuracy Mode1
DATA5
Diode2 ADC Code Gain/Range = 2 Accuracy Mode2
DATA6
Diode1 ADC Code Gain/Range = 3 Accuracy Mode1
DATA5
Diode2 ADC Code Gain/Range = 3 Accuracy Mode2
DATA6
Diode1 ADC Code Gain/Range = 4 Accuracy Mode1
DATA6
Diode2 ADC Code Gain/Range = 4 Accuracy Mode2
VREF
Voltage of REXT Pin
VTL
SCL and SDA Threshold LO
(Note 7)
1.05
V
VTH
SCL and SDA Threshold HI
(Note 7)
1.95
V
ISDA
SDA Current Sinking Capability
3
5
mA
IINT
INT Current Sinking Capability
3
5
mA
1
E = 0 lux, Mode1, Gain/Range = 1
E = 300 lux, fluorescent light,
Gain/Range = 1
(Note 6)
15760
20200
2020
Counts
E = 300 lux, fluorescent light,
Gain/Range = 2
(Note 6)
5050
Counts
505
Counts
E = 300 lux, fluorescent light,
Gain/Range = 3
(Note 6)
1262
Counts
126
Counts
E = 300 lux, fluorescent light,
Gain/Range = 4
(Note 6)
316
Counts
32
Counts
0.485
0.51
0.535
V
NOTES:
6. Fluorescent light is substituted by a green (λ = 540nm) LED during production.
7. The voltage threshold levels of the SDA and SCL pins are VDD dependent: VTL = 0.35*VDD. VTH = 0.65*VDD
8. Compliance to datasheet limits is assured by one or more methods: production test, characterization and/or design.
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ISL29003
Pin Descriptions
PIN NUMBER
PIN NAME
DESCRIPTION
1
VDD
Positive supply; connect this pin to a regulated 2.5V to 3.3V supply
2
GND
Ground pin. The thermal pad is connected to the GND pin
3
REXT
External resistor pin for ADC reference; connect this pin to ground through a (nominal) 100kΩ resistor
4
INT
Interrupt pin; LO for interrupt/alarming. The INT pin is an open drain.
5
SCL
I2C serial clock
6
SDA
I2C serial data
Principles of Operation
Photodiodes
The ISL29003 contains two photodiodes. Diode1 is sensitive
to both visible and infrared light, while Diode2 is mostly
sensitive to infrared light. The spectral response of the two
diodes are independent from one another. See Figure 7
Spectral Response vs Wavelength in the performance curves
section. The photodiodes convert light to current. Then, the
diodes’ current outputs are converted to digital by a single
built-in integrating type 16-bit Analog-to-Digital Converter
(ADC). An I2C command mode determines which photodiode
will be converted to a digital signal. Mode1 is Diode1 only.
Mode2 is Diode2 only. Mode3 is a sequential Mode1 and
Mode2 with an internal subtract function (Diode1 - Diode2).
Analog-to-Digital Converter (ADC)
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 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 8 and “Noise
Rejection” on page 9.
The built-in ADC offers the user flexibility in integration time or
conversion time. Two timing modes are available; Internal
Timing Mode and External Timing Mode. In Internal Timing
Mode, integration time is determined by an internal dual speed
oscillator (fOSC), 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 I2C External
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 I2C programmable range select to
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.
The I2C bus lines can be pulled above VDD, 5.5V max.
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 eliminates any 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.
I2C Interface
There are eight (8) 8-bit registers available inside the ISL29003.
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 ISL29003’s I2C interface slave address is hardwired
internally as 1000100. When 1000100x with x as R or W is
sent after the Start condition, this device compares the first
seven 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_iic timing
diagram sample for externally controlled integration time.
The I2C bus master always drives the SCL (clock) line, while
either the master or the slave can drive the SDA (data) line.
Figure 2 shows a sample write. Every I2C 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 I2C transaction ends with the master asserting a stop
condition (SDA rising while SCL remains high).
For more information about the I2C standard, please consult
the Philips® I2C specification documents.
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ISL29003
I2C DATA
Start
I2C SDA
In
DEVICE ADDRESS
A6
I2C SDA
Out
I2C CLK
A5
A4
A3
A2
A1
A0
W
A
W
A
SDA DRIVEN BY MASTER
1
2
3
4
5
6
REGISTER ADDRESS
R7
8
9
R5
R4
R3
R2
R1
R0
SDA DRIVEN BY MASTER
A
7
R6
A
1
2
3
4
5
6
7
8
STOP
DEVICE ADDRESS
START
A
A6
A5
A
SDA DRIVEN BY MASTER
9
1
2
A4
3
A3
A2
4
A1
5
6
A0
7
W
8
A
DATA BYTE0
A
A
SDA DRIVEN BY ISL29003
STOP
NAK
A
D7
D6
D5
D4
D3
D2
D1
D0
A
9
1
2
3
4
5
6
7
8
9
FIGURE 1. I2C READ TIMING DIAGRAM SAMPLE
I2C DATA
Start
I2C SDA In
DEVICE ADDRESS
W
A
A6 A5 A4 A3 A2 A1 A0
W
A
A
I2C SDA Out
SDA DRIVEN BY MASTER
1
I2C CLK In
2
3
4
5
6
7
8
REGISTER ADDRESS
9
A
FUNCTIONS
A
R7 R6 R5 R4 R3 R2 R1 R0
A
B7 B6 B5 B4 B3 B2 B1 B0
A
SDA DRIVEN BY MASTER
A
SDA DRIVEN BY MASTER
A
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
STOP
9
FIGURE 2. I2C WRITE TIMING DIAGRAM SAMPLE
I2 C DA TA
Start
I2 C SDA In
DEVICE ADDRESS
A6
I2 C SDA Out
A5
A4
A3
A2
A1
A0
W
A
W
A
SDA DRIV EN BY MA STER
1
I2 C CLK In
2
3
4
5
6
REGISTER ADDRESS
R7
8
9
R5
R4
R3
R2
R1
R0
SDA DRIV EN BY MA STER
A
7
R6
A Stop
1
2
3
4
5
6
7
A
A
8
9
FIGURE 3. I2C sync_iic TIMING DIAGRAM SAMPLE
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ISL29003
Register Set
There are eight registers that are available in the ISL29003. Table 1 summarizes the available registers and their functions.
TABLE 1. REGISTER SET
ADDR
(HEX)
REGISTER
NAME
BIT(S)
FUNCTION NAME
00
Command
7
Enable
0: disable ADC-core
1: enable ADC-core
6
ADCPD
0: Normal operation
1: Power-down Mode
5
Timing_Mode
4
Reserved
3:2
Mode<1:0>
Selects ADC work mode
0: Diode1’s current to unsigned 16-bit data
1: Diode2’s current to unsigned 16-bit data
2: Difference between diodes (I1 - I2) to signed 15-bit data
3: reserved
1:0
Width<1:0>
Number of clock cycles; n-bit resolution
0: 216 cycles
1: 212 cycles
2: 28 cycles
3: 24 cycles
7
Ext_Mode
Always set to logic 0. Factory use only.
6
Test_Mode
Always set to logic 0
5
Int_Flag
4
Reserved
Always set to logic 0. Factory use only.
3:2
Gain<1:0>
Selects the gain so range is
0: 0 to 1000 lux
1: 0 to 4000 lux
2: 0 to 16000 lux
3: 0 to 64000 lux
1:0
Int_Persist
<1:0>
Interrupt is triggered after
0: 1 integration cycle
1: 4 integration cycles
2: 8 integration cycles
3: 16 integration cycles
01
Control
FUNCTIONS/DESCRIPTION
0: Integration is internally timed
1: Integration is externally sync/controlled by I2C host
0: Interrupt is cleared or not yet triggered
1: Interrupt is triggered
02
Interrupt Threshold
HI
7:0
Interrupt Threshold High byte of HI interrupt threshold. Default is 0xFF
HI
03
Interrupt Threshold
LO
7:0
Interrupt Threshold High byte of the LO interrupt threshold. Default is 0x00
LO
04
LSB_Sensor
7:0
LSB_Sensor
Read-Only data register that contains the least significant byte of the
latest sensor reading.
05
MSB_Sensor
7:0
MSB_Sensor
Read-Only data register that contains the most significant byte of the
latest sensor reading.
06
LSB_Timer
7:0
LSB_Timer
Read-Only data register that contains the least significant byte of the
timer counter value corresponding to the latest sensor reading.
07
MSB_Timer
7:0
MSB_Timer
Read-Only data register that contains the most significant byte of the
timer counter value corresponding to the latest sensor reading.
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ISL29003
TABLE 2. WRITE ONLY REGISTERS
ADDRESS
REGISTER
NAME
b1xxx_xxxx
sync_iic
bx1xx_xxxx
clar_int
FUNCTIONS/
DESCRIPTION
At Mode2, the mux directs the current of Diode2 only to
the ADC. Mode3 is a sequential Mode1 and Mode2 with
an internal subtract function (Diode1 - Diode2).
TABLE 6. PHOTODIODE SELECT MODE; BITS 2 AND 3
Writing a logic 1 to this address bit
ends the current ADC-integration
and starts another. Used only with
External Timing Mode.
BITS 3:2
0:0
MODE1. ADC integrates or converts Diode1 only.
Current is converted to an n-bit unsigned data.*
Writing a logic 1 to this address bit
clears the interrupt.
0:1
MODE2. ADC integrates or coverts Diode2 only.
Current is converted to an n-bit unsigned data.*
1:0
MODE3. A sequential MODE1 then MODE2
operation. The difference current is an (n-1) signed
data.*
1:1
No Operation.
Command Register 00(hex)
The Read/Write command register has five functions:
1. Enable; Bit 7. This function either resets the ADC or
enables the ADC in normal operation. A logic 0 disables
ADC to reset-mode. A logic 1 enables adc to normal
operation.
TABLE 3. ENABLE
BIT 7
OPERATION
0
Disable ADC-Core to Reset-Mode (default)
1
Enable ADC-Core to Normal Operation
2. ADCPD; Bit 6. This function puts the device in a
power-down mode. A logic 0 puts the device in normal
operation. A logic 1 powers down the device.
TABLE 4. ADCPD
BIT 6
OPERATION
MODE
*n = 4, 8, 12,16 depending on the number of clock cycles
function.
5. Width; Bits 1 and 0. This function determines the number
of clock cycles per conversion. Changing the number of
clock cycles does more than just change the resolution of
the device; it also changes the integration time, which is
the period the device’s analog-to-digital (A/D) converter
samples the photodiode current signal for a lux
measurement.
TABLE 7. WIDTH
BITS 1:0
NUMBER OF CLOCK CYCLES
0:0
216 = 65,536
0:1
212 = 4,096
0
Normal Operation (default)
1:0
28 = 256
1
Power-Down
1:1
24 = 16
For proper shut down operation, it is recommended to
disable ADC first then disable the chip. Specifically, the user
should first send I2C command with Bit 7 = 0 and then send
I2C command with Bit 6 = 1.
3. Timing Mode; Bit 5. This function determines whether the
integration time is done internally or externally. In Internal
Timing Mode, integration time is determined by an
internal dual speed oscillator (fOSC), 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 external-sync sync_iic pulse commands.
Control Register 01(hex)
The Read/Write control register has three functions:
1. Interrupt flag; Bit 5. This is the status bit of the interrupt.
The bit is set to logic high when the interrupt thresholds
have been triggered, and logic low when not yet
triggered. Writing a logic low clears/resets the status bit.
TABLE 8. INTERRUPT FLAG
BIT 5
OPERATION
0
Interrupt is cleared or not triggered yet
1
Interrupt is triggered
TABLE 5. TIMING MODE
BIT 5
OPERATION
0
Internal Timing Mode. Integration time is internally
timed determined by fOSC, REXT, and number of
clock cycles.
1
External Timing Mode. Integration time is externally
timed by the I2C host.
2. Range/Gain; Bits 3 and 2. The Full Scale Range can be
adjusted by an external resistor REXT and/or it can be
adjusted via I2C using the Gain/Range function.
Gain/Range has four possible values, Range(k) where k
is 1 through 4. Table 9 lists the possible values of
Range(k) and the resulting FSR for some typical value
REXT resistors.
4. Photodiode Select Mode; Bits 3 and 2. This function
controls the mux attached to the two photodiodes. At
Mode1, the mux directs the current of Diode1 to the ADC.
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ISL29003
TABLE 9. RANGE/GAIN TYPICAL FSR LUX RANGES
FSR LUX
FSR LUX
FSR LUX
RANGE@
RANGE@
RANGE@
BITS
3:2 k RANGE (k) REXT = 100k REXT = 50k REXT = 500k
TABLE 11. DATA REGISTERS
ADDRESS
(hex)
CONTENTS
04
Least-significant byte of most recent sensor reading.
0:0
1
973
973
1946
195
05
Most-significant byte of most recent sensor reading.
0:1
2
3892
3892
7784
778
06
1:0
3
15,568
15,568
31,136
3114
Least-significant byte of timer counter value
corresponding to most recent sensor reading.
1:1
4
62,272
62,272
124,544
12,454
07
Most-significant byte of timer counter value
corresponding to most recent sensor reading.
3. Interrupt persist; Bits 1 and 0. The interrupt pin and the
interrupt flag is triggered/set when the data sensor
reading is out of the interrupt threshold window after m
consecutive number of integration cycles. The interrupt
persist bits determine m.
TABLE 10. INTERRUPT PERSIST
BITS 1:0
NUMBER OF INTEGRATION CYCLES
0:0
1
0:1
4
1:0
8
1:1
16
Interrupt Threshold HI Register 02(hex)
This register sets the HI threshold for the interrupt pin and
the interrupt flag. By default, the Interrupt threshold HI is
FF(hex). The 8-bit data written to the register represents the
upper MSB of a 16-bit value. The LSB is always 00(hex).
Interrupt Threshold LO Register 03(hex)
This register sets the LO threshold for the interrupt pin and
the interrupt flag. By default, the Interrupt threshold LO is
00(hex). The 8-bit data written to the register represents the
upper MSB of a 16-bit value. The LSB is always 00(hex).
Sensor Data Register 04(hex) and 05(hex)
When the device is configured to output a 16-bit data, the
least significant byte is accessed at 04(hex), and the most
significant byte can be accessed at 05(hex). The sensor data
register is refreshed after every integration cycle.
Timer Data Register 06(hex) and 07(hex)
Note that the timer counter value is only available when
using the External Timing Mode. The 06(hex) and 07(hex)
are the LSB and MSB respectively of a 16-bit timer counter
value corresponding to the most recent sensor reading.
Each clock cycle increments the counter. At the end of each
integration period, the value of this counter is made available
over the I2C. This value can be used to eliminate noise
introduced by slight timing errors caused by imprecise
external timing. Microcontrollers, for example, often cannot
provide high-accuracy command-to-command timing, and
the timer counter value can be used to eliminate the
resulting noise.
7
Calculating Lux
The ISL29003’s output codes, DATA, are directly
proportional to lux.
E = α × DATA
(EQ. 1)
The proportionality constant α is determined by the Full
Scale Range, FSR, and the n-bit ADC, which is user defined
in the command register. The proportionality constant can
also be viewed as the resolution; The smallest lux
measurement the device can measure is α.
FSR
α = -----------n
2
(EQ. 2)
Full Scale Range, FSR, is determined by the software
programmable Range/Gain, Range(k), in the command
register and an external scaling resistor REXT which is
referenced to 100kΩ.
(EQ. 3)
100kΩ
FSR = Range ( k ) × -----------------R EXT
The transfer function effectively for each timing mode
becomes:
INTERNAL TIMING MODE
100kΩ
Range ( k ) × -----------------R EXT
E = ---------------------------------------------------- × DATA
n
2
(EQ. 4)
EXTERNAL TIMING MODE
100kΩ
Range ( k ) × -----------------R EXT
E = ---------------------------------------------------- × DATA
COUNTER
(EQ. 5)
n = 4, 8, 12, or 16. This is the number of clock cycles
programmed in the command register.
Range(k) is the user defined range in the Gain/Range bit in
the command register.
REXT is an external scaling resistor hardwired to the REXT
pin.
DATA is the output sensor reading in number of counts
available at the data register.
2n represents the maximum number of counts possible in
Internal Timing Mode. For the External Timing Mode, the
maximum number of counts is stored in the data register
named COUNTER.
FN7464.6
November 17, 2011
ISL29003
COUNTER is the number increments accrued for between
integration time for External Timing Mode.
Gain/Range, Range (k)
The Gain/Range can be programmed in the control register
to give Range (k) determining the FSR. Note that Range(k)
is not the FSR (see Equation 3). Range(k) provides four
constants depending on programmed k that will be scaled by
REXT (see Table 9). Unlike REXT, Range(k) dynamically
adjusts the FSR. This function is especially useful when light
conditions are varying drastically while maintaining excellent
resolution.
Number of Clock Cycles, n-bit ADC
The number of clock cycles determines “n” in the n-bit ADC; 2n
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 = 4. For maximum resolution without regard of
time, choose n = 16. Table 12 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.
n
tINT (ms)
(EQ. 8)
1
f OSC 1 = --- ( f OSC 2 )
2
The automatic fOSC adjustment feature allows significant
improvement of signal-to-noise ratio when detecting very low
lux signals.
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 ISL29003 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
TABLE 12. RESOLUTION AND INTEGRATION TIME
SELECTION
RANGE1
fOSC = 327kHz
When the Range/Gain bits are set to Range1 or Range2,
fOSC runs at half speed compared to when Range/Gain bits
are set to Range3 and Range4.
RANGE4
fOSC = 655kHz
RESOLUTION
RESOLUTION
LUX/COUNT tINT (ms) (LUX/COUNT)
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, fOSC and
n-bits resolution determine the integration time. tint is a
function of the number of clock cycles and fOSC.
n
1
t int = 2 × ---------f osc
16
200
0.01
100
1
12
12.8
0.24
6.4
16
8
0.8
3.90
0.4
250
4
0.05
62.5
0.025
4000
REXT = 100kΩ
External Scaling Resistor REXT and fosc
The ISL29003 uses an external resistor REXT to fix its
internal oscillator frequency, fOSC. Consequently, REXT
determines the fOSC, integration time and the FSR of the
device. fOSC, a dual speed mode oscillator, is inversely
proportional to REXT. For user simplicity, the proportionality
constant is referenced to fixed constants 100kΩ and
655kHz:
1 100kΩ
fosc1 = --- × ------------------ × 655 kHz
2 R EXT
(EQ. 6)
100kΩ
fosc2 = ------------------ × 655 kHz
R EXT
(EQ. 7)
fOSC1 is oscillator frequency when Range1 or Range2 are
set. This is nominally 327kHz when REXT is 100kΩ.
for Internal Timing Mode only
(EQ. 9)
n = 4, 8, 12, and16. n is the number of bits of resolution.
Therefore, 2n is the number of clock cycles. n can be
programmed at the command register 00(hex) bits 1 and 0.
Since fOSC is dual speed depending on the Gain/Range bit,
tint is dual time. The integration time as a function of REXT
and n is:
R EXT
n
t int 1 = 2 × ---------------------------------------------327kHz × 100kΩ
(EQ. 10)
tint1 is the integration time when the device is configured for
Internal Timing Mode and Gain/Range is set to Range1 or
Range2.
R EXT
n
t int 2 = 2 × ---------------------------------------------655kHz × 100kΩ
(EQ. 11)
tint2 is the integration time when the device is configured for
Internal Timing Mode and Gain/Range is set to Range3 or
Range4.
fOSC2 is the oscillator frequency when Range3 or Range4
are set. This is nominally 655kHz when REXT is 100kΩ.
8
FN7464.6
November 17, 2011
ISL29003
TABLE 13. INTEGRATION TIMES FOR TYPICAL REXT VALUES
RANGE1
RANGE2
RANGE3
RANGE4
REXT
(kΩ)
n = 16-BIT
n = 12-BIT
n = 12-BIT
n=4
50
100
6.4
3.2
0.013
100**
200
13
6.5
0.025
200
400
26
13
0.050
500
1000
64
32
0.125
*Integration time in milliseconds
**Recommended REXT resistor value
INTEGRATION TIME IN EXTERNAL TIMING MODE
This timing mode is programmed in the command register
00(hex) bit 5. External Timing Mode is recommended when
integration time can be synchronized to an external signal
(such as a PWM) to eliminate noise.
For Mode1 or Mode2 operation, the integration starts when
the sync_iic command is sent over the I2C lines. The device
needs two sync_iic commands to complete a photodiode
conversion. The integration then stops when another
sync_iic command is received. Writing a logic 1 to the
sync_iic bit ends the current ADC integration and starts
another one.
For Mode3, the operation is a sequential Mode1 and Mode2.
The device needs three sync_iic commands to complete two
photodiode measurements. The 1st sync_iic command starts
the conversion of the Diode1. The 2nd sync_iic completes the
conversion of Diode1 and starts the conversion of Diode2.
The 3rd sync_iic pulse ends the conversion of Diode2 and
starts over again to commence conversion of Diode1.
The integration time, tint, is determined by Equation 12:
iI 2 C
t int = ---------fI 2 C
(EQ. 12)
iI2C is the number of I2C clock cycles to obtain the tint.
fI2C is the I2C operating frequency.
The internal oscillator, fOSC, operates identically in both the
internal and external timing modes, with the same
dependence on REXT. However, in External Timing Mode,
the number of clock cycles per integration is no longer fixed
at 2n. The number of clock cycles varies with the chosen
integration time, and is limited to 216 = 65,536. In order to
avoid erroneous lux readings, the integration time must be
short enough not to allow an overflow in the counter register.
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 integration
time. For instance, a 60Hz AC unwanted signal’s sum from
0ms to k*16.66ms (k = 1,2...ki) is zero. Similarly, setting the
device’s integration time to be an integer multiple of the
periodic noise signal greatly improves the light sensor output
signal in the presence of noise.
DESIGN EXAMPLE 1
The ISL29003 will be designed in a portable system. The
ambient light conditions that the device will be exposed to is
at most 500 lux, which is a good office lighting. The light
source has a 50/60Hz power line noise, which is not visible
by the human eye. The I2C clock is 10kHz.
Solution 1
Using Internal Timing Mode
In order to achieve both 60Hz and 50Hz AC noise rejection,
the integration time needs to be adjusted to coincide with an
integer multiple of the AC noise cycle times.
t int = i ( 1 ⁄ 60Hz ) = j ( 1 ⁄ 50Hz )
(EQ. 14)
The first instance of integer values at which tint rejects both
60Hz and 50Hz is when i = 6, and j = 5.
t int = 6 ( 1 ⁄ 60Hz ) = 5 ( 1 ⁄ 50Hz )
(EQ. 15)
t int = 100ms
Next, the Gain/Range needs to be determined. Based on the
application condition given, lux(max) = 500 lux, a range of
1000 lux is desirable. This corresponds to a Gain/Range
Range1 mode. Also impose a resolution of n = 16-bit.
Hence, we choose Equation 10 to determine REXT.
t int × 327kHz × 100 kΩ
R EXT = ------------------------------------------------------------n
2
(EQ. 16)
R EXT = 50kΩ
for Internal Timing Mode and Gain/Range is set to Range3 or Range4 only
The Full Scale Range, FSR, needs to be determined from
Equation 3:
100kΩ
FSR = 1000 lux -----------------50kΩ
(EQ. 17)
FSR = 2000 lux
The effective transfer function becomes:
65,535
t int < -----------------f OSC
(EQ. 13)
data
E = ------------- × 2000 lux
16
2
(EQ. 18)
fOSC = 327kHz*100kΩ/REXT. When Range/Gain is set to
Range1 or Range2.
fOSC = 655kHz*100kΩ/REXT. When Range/Gain is set to
Range3 or Range4.
9
FN7464.6
November 17, 2011
ISL29003
TABLE 14. SOLUTION1 SUMMARY TO EXAMPLE DESIGN
PROBLEM
DESIGN PARAMETER
VALUE
tint
100ms
REXT
50kΩ
Gain/Range Mode
Range1 = 1000 lux
FSR
2000 lux
# of clock cycles
216
Transfer Function
DATA
E = ----------------- × 2000 lux
16
2
Solution 2
IR Rejection
Any filament type light source has a high presence of infrared
component invisible to the human eye. A white fluorescent
lamp, on the other hand has a low IR content. As a result,
output sensitivity may vary depending on the light source.
Maximum attenuation of IR can be achieved by properly
scaling the readings of Diode1 and Diode2. The user obtains
data reading from sensor Diode1 (D1), which is sensitive to
visible and IR, then reading from sensor Diode2 (D2), which is
mostly sensitive from IR. The graph in Figure 7 shows the
effective spectral response after applying Equation 19 of the
ISL29003 from 400nm to 1000nm. Equation 19 describes the
method of cancelling IR in internal timing mode.
D3 = n ( D1 – kD2 )
Using External Timing Mode
From Solution 1, the desired integration time is 100ms. Note
that the REXT resistor only determines the inter oscillator
frequency when using external timing mode. Instead, the
integration time is the time between two sync_iic commands
sent through the I2C. The programmer determines how
many I2C clock cycles to wait between two external timing
commands.
iI2C = fI2C*tint = number of I2C clock cycles
iI2C = 10kHz *100ms
iI2C = 1,000 I2C clock cycles. An external sync_iic command
sent 1,000 cycles after another sync_iic command rejects
both 60Hz and 50Hz AC noise signals.
Next, is to pick an arbitrary REXT = 100kΩ and to choose the
Gain/Range Mode. For a maximum 500 lux, Range1 is
adequate. From Equation 3:
100kΩ
FSR = 1000 lux -----------------100kΩ
FSR = 1000 lux
The effective transfer function becomes:
DATA
E = -------------------------------- × 1000 lux
COUNTER
DATA is the sensor reading data located in data registers
04(hex) and 05(hex)
(EQ. 19)
Where:
data = lux amount in number of counts less IR presence
D1 = data reading of Diode1
D2 = data reading of Diode2
n = 1.85. This is a fudge factor to scale back the sensitivity
up to ensure Equation 4 is valid.
k = 7.5. This is a scaling factor for the IR sensitive Diode2.
Flat Window Lens Design
A window lens will surely limit the viewing angle of the
ISL29003. The window lens should be placed directly on top
of the device. The thickness of the lens should be kept at
minimum to minimize loss of power due to reflection and
also to minimize loss of loss due to absorption of energy in
the plastic material. A thickness of t = 1mm is recommended
for a window lens design. The bigger the diameter of the
window lens, the wider the viewing angle is of the ISL29003.
Table 16 shows the recommended dimensions of the optical
window to ensure both 35° and 45° viewing angle. These
dimensions are based on a window lens thickness of 1.0mm
and a refractive index of 1.59.
WINDOW LENS
COUNTER is the timer counter value data located in data
registers 06(hex) and 07(hex). In this sample problem,
COUNTER = 1000.
t
DESIGN PARAMETER
VALUE
tint
100ms
REXT
100kΩ
Gain/Range Mode
Range1 = 1000 lux
FSR
1000 lux
# of clock cycles
COUNTER = 1000
Transfer Function
DATA
E = -------------------------------- × 1000 lux
COUNTER
10
DTOTAL
∅
TABLE 15. SOLUTION2 SUMMARY TO EXAMPLE DESIGN
PROBLEM
ISL29003
D1
DLENS
∅ = Viewing angle
FIGURE 4. FLAT WINDOW LENS
FN7464.6
November 17, 2011
ISL29003
Suggested PCB Footprint
TABLE 16. RECOMMENDED DIMENSIONS FOR A FLAT
WINDOW DESIGN
DTOTAL
D1
DLENS @ 35°
VIEWING ANGLE
1.5
0.50
2.25
3.75
2.0
1.00
3.00
4.75
2.5
1.50
3.75
5.75
3.0
2.00
4.30
6.75
3.5
2.50
5.00
7.75
t=1
D1
DLENS
DTOTAL
DLENS @ 45°
VIEWING ANGLE
Footprint pads should be a nominal 1-to-1 correspondence
with package pads. Since ambient light sensor devices do
not dissipate high power, heat dissipation through the
exposed pad is not important; instead, similar to DFN or
QFN, the exposed pad provides robustness in board mount
process. Intersil recommends mounting the exposed pad to
the PCB, but this is not mandatory.
Layout Considerations
The ISL29003 is relatively insensitive to layout. Like other
I2C devices, it is intended to provide excellent performance
even in significantly noisy environments. There are only a
few considerations that will ensure best performance.
Thickness of lens
Distance between ISL29001 and inner edge of lens
Diameter of lens
Distance constraint between the ISL29001 and lens
outer edge
Route the supply and I2C traces as far as possible from all
sources of noise. Use two power-supply decoupling
capacitors, 4.7µF and 0.1µF, placed close to the device.
*All dimensions are in mm.
2.00mm
SENSOR OFFSET
2.10mm
Typical Circuit
1
6
2
5
A typical application for the ISL29003 is shown in Figure 6.
The ISL29003’s I2C address is internally hardwired as
1000100. The device can be tied onto a system’s I2C bus
together with other I2C compliant devices.
0.29mm
Soldering Considerations
0.56mm
3
Convection heating is recommended for reflow soldering;
direct-infrared heating is not recommended. The plastic
ODFN package does not require a custom reflow soldering
profile, and is qualified to +260°C. A standard reflow
soldering profile with a +260°C maximum is recommended.
4
0.46mm
FIGURE 5. SENSOR LOCATION DRAWING
1.8V TO 5.5V
R1
10k
R2
10k
I2C MASTER
R3
RES1
MICROCONTROLLER
SDA
SCL
2.5V TO 3.3V
I2C SLAVE_1
I2C SLAVE_0
1
2
C1
C2
4.7µF 0.1µF
3
VDD
SDA
GND
SCL
REXT
INT
REXT
100k
I2C SLAVE_n
6
SDA
SDA
5
SCL
SCL
4
ISL29003
FIGURE 6. ISL29003 TYPICAL CIRCUIT
11
FN7464.6
November 17, 2011
ISL29003
Typical Performance Curves (REXT = 100kΩ)
NORMALIZED RESPONSE (%)
100
RADIATION PATTERN
90
ISL29003 D1
80
LUMINOSITY 30º
ANGLE
40º
70
60
50
0º
10º
20º
30º
40º
50º
60º
60º
40
ISL29003 D2
30
70º
70º
20
10
400
500
600
700
800
WAVELENGTH (nm)
900
80º
80º
90º
90º
0.2 0.4
0.6 0.8 1.0
RELATIVE SENSITIVITY
1k
FIGURE 8. RADIATION PATTERN
FIGURE 7. SPECTRAL RESPONSE
320
10
TA = +27°C
COMMAND = 00H
OUTPUT CODE (COUNTS)
306
5000 lux
292
278
200 lux
264
250
2.0
2.3
2.6
2.9
3.2
3.5
8
TA = +27°C
COMMAND = 00H
0 lux
6
4
2
0
2.0
3.8
RANGE 2
2.3
SUPPLY VOLTAGE (V)
2.9
3.2
3.5
3.8
FIGURE 10. OUTPUT CODE FOR 0 LUX vs SUPPLY VOLTAGE
1.015
1.010
5000 lux
1.005
1.000
200 lux
0.995
2.3
2.6
2.9
3.2
3.5
SUPPLY VOLTAGE (V)
FIGURE 11. OUTPUT CODE vs SUPPLY VOLTAGE
12
3.8
OSCILLATOR FREQUENCY (kHz)
320.0
TA = +27°C
COMMAND = 00H
0.990
2.0
2.6
SUPPLY VOLTAGE (V)
FIGURE 9. SUPPLY CURRENT vs SUPPLY VOLTAGE
OUTPUT CODE RATIO
(% FROM 3V)
10º
50º
0
300
SUPPLY CURRENT (mA)
20º
TA = +27°C
319.5
319.0
318.5
318.0
2.0
2.3
2.6
2.9
3.2
3.5
3.8
SUPPLY VOLTAGE (V)
FIGURE 12. OSCILLATOR FREQUENCY vs SUPPLY VOLTAGE
FN7464.6
November 17, 2011
ISL29003
Typical Performance Curves (REXT = 100kΩ)
(Continued)
315
10
OUTPUT CODE (COUNTS)
SUPPLY CURRENT (µA)
VDD = 3V
COMMAND = 00H
305
5000 lux
295
RANGE 3
285
200 lux
RANGE 1
275
265
-60
-20
20
60
8
6
4
2
0
-60
100
VDD = 3V
COMMAND = 00H
0 lux
RANGE 2
-20
TEMPERATURE (°C)
FIGURE 13. SUPPLY CURRENT vs TEMPERATURE
OSCILLATOR FREQUENCY (kHz)
OUTPUT CODE RATIO
(% FROM +25°C)
100
330
VDD = 3V
COMMAND = 00H
1.048
5000 lux
200 lux
RANGE 3
0.984
RANGE 1
0.952
0.920
-60
60
FIGURE 14. OUTPUT CODE FOR 0 LUX vs TEMPERATURE
1.080
1.016
20
TEMPERATURE (°C)
-20
20
60
TEMPERATURE (°C)
FIGURE 15. OUTPUT CODE vs TEMPERATURE
100
VDD = 3V
329
328
327
326
325
-60
-20
20
TEMPERATURE (°C)
60
100
FIGURE 16. OSCILLATOR FREQUENCY vs TEMPERATURE
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9001 quality systems.
Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
13
FN7464.6
November 17, 2011
ISL29003
Package Outline Drawing
L6.2x2.1
6 LEAD OPTICAL DUAL FLAT NO-LEAD PLASTIC PACKAGE (ODFN)
Rev 3, 5/11
2.10
A
6
PIN #1
INDEX AREA
B
6
PIN 1
INDEX AREA
1
0.65
1.35
2.00
1.30 REF
4 6X 0.30±0.05
(4X)
0.10
0.10 M C A B
0.65
TOP VIEW
6x0.35 ± 0.05
BOTTOM VIEW
2.50
PACKAGE
OUTLINE
2.10
SEE DETAIL "X"
0.65
(4x0.65)
0.10 C
MAX 0.75
C
BASE PLANE
SEATING PLANE
0.08 C
SIDE VIEW
(1.35)
(6x0.30)
C
(6x0.20)
0 . 2 REF
5
0 . 00 MIN.
0 . 05 MAX.
(6x0.55)
TYPICAL RECOMMENDED LAND PATTERN
DETAIL "X"
NOTES:
1.
Dimensions are in millimeters.
Dimensions in ( ) for Reference Only.
2.
Dimensioning and tolerancing conform to ASME Y14.5m-1994.
3.
Unless otherwise specified, tolerance : Decimal ± 0.05
4.
Dimension applies to the metallized terminal and is measured
between 0.15mm and 0.30mm from the terminal tip.
5.
Tiebar shown (if present) is a non-functional feature.
6.
The configuration of the pin #1 identifier is optional, but must be
located within the zone indicated. The pin #1 identifier may be
either a mold or mark feature.
14
FN7464.6
November 17, 2011