DATASHEET

ISL29015
Data Sheet
October 31, 2008
Integrated Digital Ambient Light Sensor
and Proximity Sensor
The ISL29015 is an integrated ambient and infrared light to
digital converter with a built-in IR LED driver and I2C/SMBus
interface. This device provides not only ambient light sensing
to allow robust backlight/display brightness control but also
infrared sensing to allow proximity estimation.
For ambient light sensing, an internal 16-bit ADC has been
designed based on the charge-balancing A/D conversion
technique. The ADC conversion time is nominally 100ms
and is user adjustable from 25µs to 100ms depends on
oscillator frequency and ADC resolution. This ADC is
capable of rejecting 50Hz and 60Hz flicker noise caused by
artificial light sources. The lux-range-select feature allows
users to program the lux range for optimized counts/lux.
For proximity sensing, the ADC is used to digitize the output
signal from the photodiode array when the internal IR LED
driver is turned on and off for the programmed time periods
under user-selected modulation frequency to drive the
external IR LED. As this proximity sensor employs a noise
cancellation scheme to highly reject unwanted IR noise, the
digital output of proximity sensing decreases with distance.
The driver output current is user selectable up to 100mA to
drive different types of IR emitters LEDs.
Six different modes of operation can be selected via the I2C
interface: Programmable ALS once with auto power-down,
programmable IR sensing once, programmable proximity
sensing once, programmable continuous ALS sensing,
programmable continuous IR sensing and programmable
continuous proximity sensing. The programmable one-time
operation modes greatly reduce power because an
immediate automatic shutdown reduces overall supply
current less than 1µA.
Designed to operate on supplies from 2.25V to 3.3V, the
ISL29015 is specified for operation over the -40°C to +85°C
ambient temperature range. It is packaged in a clear, Pb-free
6 Ld ODFN package.
Pinout
ISL29015
(6 LD ODFN)
TOP VIEW
FN6522.0
Features
Proximity Sensing
• Ambient IR Cancellation During Proximity Sensing
- Works Under Direct Sunlight
• IR LED Driver with Programmable Source Current
- Adjustable Current Drive from 100mA to 12.5mA
• Programmable LED current Modulation Frequency
• Variable Conversion Resolution up to 16-bits
Ambient Light Sensing
• Simple Output Code Directly Proportional to lux
• Adjustable Sensitivity up to 65 Counts per lux
• Selectable Range (via I2C)
- Range 1 = 0.015 lux to 1,000 lux
- Range 2 = 0.06 lux to 4,000 lux
- Range 3 = 0.24 lux to 16,000 lux
- Range 4 = 0.96 lux to 64,000 lux
• Integrated 50/60Hz Noise Rejection
• Works Under Various Light Sources, Including Sunlight
Ideal Spectral Response for Light and Proximity Sensor
• Light Sensor Close to Human Eye Response
- Excellent Light Sensor IR and UV Rejection
• Proximity sensor range from 850nm to 950nm
- Can use either 850nm or 950nm LED solution
Ultra Low Power
• 90μA Max Operating Current
- 1.0μA Max Shutdown Current
• Software Shutdown and Automatic Shutdown
Easy to Use
• I2C (SMBus Compatible) Output
• No Complex Algorithms Needed
• Temperature Compensated
• Small Form Factor
- 2.0x2.1x0.7mm 6 Ld ODFN Package
Additional Features
•
•
•
•
I2C and SMBus Compatible
1.7V to 3.63V Supply for I2C Interface
2.25V to 3.3V Supply
Pb-Free (RoHS compliant)
Applications
VDD 1
6 IRDR
GND 2
5 SDA
REXT 3
4 SCL
• Display and Keypad Dimming Adjustment and Proximity
Sensing for:
- Mobile Devices: Smart Phone, PDA, GPS
- Computing Devices: Notebook PC, Webpad
- Consumer Devices: LCD-TV, Digital Picture Frame, Digital
Camera
• Industrial and Medical Light and Proximity Sensing
*EXPOSED PAD CAN BE CONNECTED TO GND OR
ELECTRICALLY ISOLATED
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 2008. All Rights Reserved
Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.
All other trademarks mentioned are the property of their respective owners.
ISL29015
Ordering Information
PART NUMBER
(Note)
TEMP. RANGE
(°C)
ISL29015IROZ-T7*
-40 to +85
ISL29015IROZ-EVALZ
PACKAGE
(Pb-Free)
PKG.
DWG. #
6 Ld ODFN
L6.2x2.1
Evaluation Board
*Please refer to TB347 for details on reel specifications.
NOTE: These Intersil Pb-free plastic packaged products employ special Pb-free material sets; molding compounds/die attach materials and
NiPdAu plate - e4 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.
Pin Descriptions
PIN NUMBER
PIN NAME
DESCRIPTION
1
VDD
Positive supply: 2.25V to 3.3V.
2
GND
Ground pin.
3
REXT
External resistor pin setting the internal reference current and the conversion time. 499kΩ with 1%
tolerance resistor is recommended.
4
SCL
I2C serial clock line
5
SDA
I2C serial data line
6
IRDR
IR LED driver pin connecting to the anode of the external IR LED. The source current of the IR LED driver
can be programmed through I2C.
The I2C bus lines can be pulled from 1.7V to above VDD, 3.63V max.
Exposed pad connected to ground or electrically isolated.
Block Diagram
VDD
1
PHOTODIODE
ARRAY
COMMAND
REGISTER
LIGHT DATA
PROCESS
ALS AND IR
INTEGRATION
ADC
DATA
REGISTER
I2C
IR PHOTODIODE
ARRAY
5
SDA
4
SCL
6
IRDR
IREF
IR DRIVER
FOSC
3
2
REXT
GND
ISL29015
2
FN6522.0
October 31, 2008
ISL29015
Absolute Maximum Ratings (TA = +25°C)
Thermal Information
VDD Supply Voltage between VDD and GND . . . . . . . . . . . . . 3.6V
I2C Bus (SCL, SDA) Pin Voltage . . . . . . . . . . . . . . . . . . -0.2V to 4V
I2C Bus (SCL, SDA) Pin Current . . . . . . . . . . . . . . . . . . . . . <10mA
IRDR Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . -0.2V to VDD + 0.5V
REXT Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . -0.2V to VDD + 0.5V
ESD Rating
Human Body Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2kV
Thermal Resistance (Typical, Note 1)
θJA (°C/W)
6 Ld ODFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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:
1. 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 = 499kΩ 1% tolerance, 16-bit ADC operation, unless
otherwise specified.
DESCRIPTION
VDD
Power Supply Range
CONDITION
MIN
TYP
2.25
MAX
UNIT
3.3
V
IDD
Supply Current when Powered Down Software disabled or auto power-down
0.1
1
µA
IDD1
Supply Current of Ambient Light and
IR Sensing
70
90
µA
VI2C
Supply Voltage Range for I2C
Interface
3.63
V
800
kHz
1.7
fOSC
Internal Oscillator Frequency
tint
ADC Integration/Conversion Time
650
FI2C
I2C Clock Rate Range
DATA_0
Count Output When Dark
DATA_FS
Full Scale ADC Code
ΔDATA
DATA
Count Output Variation Over Three
Light Sources: Fluorescent,
Incandescent and Sunlight
Ambient light sensing
DATA_1
Light Count Output With LSB of
0.015 lux/count
E = 300 lux, Fluorescent light (Note 2), Ambient light
sensing, Range 1 (1k lux)
DATA_2
Light Count Output With LSB of
0.06 lux/count
E = 300 lux, Fluorescent light (Note 2), Ambient light
sensing, Range 2 (4k lux)
5000
Counts
DATA_3
Light Count Output With LSB of
0.024 lux/count
E = 300 lux, Fluorescent light (Note 2), Ambient light
sensing, Range 3 (16k lux)
1250
Counts
DATA_4
Light Count Output With LSB of
0.96 lux/count
E = 300 lux, Fluorescent light (Note 2), Ambient light
sensing, Range 4 (64k lux)
312
Counts
16-bit ADC data
725
90
ms
1 to 400
E = 0 lux
1
kHz
5
Counts
65535
Counts
±10
15000
20000
25000
25000
Counts
DATA_IR1
Infrared Count Output
E = 210 lux, Sunlight (Note 3), IR sensing, Range 1
DATA_IR2
Infrared Count Output
E = 210 lux, Sunlight (Note 3), IR sensing, Range 2
5000
Counts
DATA_IR3
Infrared Count Output
E = 210 lux, Sunlight (Note 3), IR sensing, Range 3
1250
Counts
DATA_IR4
Infrared Count Output
E = 210 lux, Sunlight (Note 3), IR sensing, Range 4
312
Counts
VREF
Voltage of REXT Pin
0.52
V
VIL
SCL and SDA Input Low Voltage
VIH
SCL and SDA Input High Voltage
3
15000
20000
%
0.6
1.5
Counts
V
V
FN6522.0
October 31, 2008
ISL29015
Electrical Specifications
PARAMETER
VDD = 3V, TA = +25°C, REXT = 499kΩ 1% tolerance, 16-bit ADC operation, unless
otherwise specified. (Continued)
DESCRIPTION
CONDITION
ISDA
SDA Current Sinking Capability
IIRDR1
IRDR Source Current
IS<1:0> = 0 (Note 4)
IIRDR2
IRDR Source Current
IS<1:0> = 1 (Note 4)
IIRDR3
IRDR Source Current
IS<1:0> = 2 (Note 4)
IIRDR4
IRDR Source Current
IS<1:0> = 3 (Note 4)
VIRLED
Voltage Head Room of IRDR Pin
tr
Rise Time for IRDR Source Current
tf
Fall Time for IRDR Source Current
MIN
4
1.5V at IRDR pin
44
TYP
MAX
UNIT
5
mA
100
mA
50
56
mA
25
mA
12.5
mA
VDD - 0.6
V
RLOAD = 15Ω at IRDR pin, 20% to 80%
35
ns
RLOAD = 15Ω at IRDR pin, 80% to 20%
10
ns
fIRLED1
IR LED Modulation Frequency
Freq<1:0> = 0 (Note 4)
DC
kHz
fIRLED2
IR LED Modulation Frequency
Freq<1:0> = 3 (Note 4)
360
kHz
IDD (IRLED1)
Supply Current of Proximity Sensing IS<1:0> = 0, Freq<1:0> = 0 (Note 4)
101
mA
IDD (IRLED2)
Supply Current of Proximity Sensing IS<1:0> = 0, Freq<1:0> = 3 (Note 4)
51
mA
Duty Cycle
Duty Cycle of IR LED Modulation
50
%
PROX-IR
PROX
Differential ADC Output of IR and
Proximity Sensing With Object Far
Away to Provide No Reflection
2.0
%
IR and proximity sensing with Range 2; 1.5V @ IRDR
pin, IS<1:0> = 0, Freq<1:0> = 0; E = 210 lux, Sunlight.
NOTES:
2. 550nm green LED is used in production test. The 550nm LED irradiance is calibrated to produce the same DATA count against an illuminance
level of 300 lux fluorescent light.
3. 850nm infrared LED is used in production test. The 850nm LED irradiance is calibrated to produce the same DATA_IR count against an
illuminance level of 210 lux sunlight at sea level.
4. See “Register Set” on page 6.
Principles of Operation
Photodiodes and ADC
The ISL29015 contains two photodiode arrays which convert
light into current. The spectral response for ambient light
sensing and IR sensing is shown in Figure 6 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 I2C
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.
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 (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 “Integration and Conversion Time” on page 7.
A good balancing act of integration time and resolution
depending on the application is required for optimal results.
4
The ADC has I2C programmable range select to dynamically
accommodate various lighting conditions. For very dim
conditions, the ADC can be configured at its lowest range
(Range 1) in the ambient light sensing. For very bright
conditions, the ADC can be configured at its highest range
(Range 4) in the proximity sensing.
Low-Power Operation
The ISL29015 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 ISL29015 receives an I2C
command to do a one-time measurement from an I2C master, it
will start ADC conversion with light or proximity 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 ISL29015 will
continuously do ADC conversion with light or proximity sensing
if it receives an I2C command of continuous 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 I2C command of power-down.
Ambient Light, IR and Proximity Sensing
There are six operational modes in ISL29015: Programmable
ALS once with auto power-down, programmable IR sensing
once with auto power-down, programmable proximity sensing
once with auto power-down; programmable continuous ALS
sensing, programmable continuous IR sensing and
FN6522.0
October 31, 2008
ISL29015
I2C Interface
programmable continuous proximity sensing. These six modes
can be programmed in series to fulfill the application needs.
The detailed program configuration is listed in “Register Set” on
page 6.
There are four 8-bit registers available inside the ISL29015.
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.
When the part is programmed for ambient light sensing, the
ambient light with wavelength within the “Ambient Light
Sensing” spectral response curve in Figure 6 is converted
into current. With ADC, the current is converted to an
unsigned n-bit (up to 16 bits) digital output.
The ISL29015’s I2C interface slave address is internally
hardwired 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.
When the part is programmed for infrared (IR) sensing, the
IR light with wavelength within the “IR or Proximity Sensing”
spectral response curve on Figure 6 is converted into
current. With ADC, the current is converted to an unsigned
n-bit (up to 16 bits) digital output.
Figure 1 shows a sample one-byte read. Figure 2 shows a
sample one-byte write. 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).
When the part is programmed for proximity sensing, the
external IR LED is turned on by the built-in IR LED driver
through the IRDR pin. The amplitude of the IR LED current
and the IR LED modulation frequency can be programmed
through Command Register II. When the IR from the LED
reaches an object and gets reflected back, the reflected IR
light with wavelength within the “IR or Proximity Sensing”
spectral response curve in Figure 6 is converted into current.
With ADC, the current is converted to an unsigned n-bit (up
to 16 bits) digital output. The output reading is inversely
proportional to the square of the distance between the
sensor and the object. When there is significant background
IR noise like direct sunlight, both IR and proximity sensing
can be implemented for background noise cancellation. The
differential output reading from the ADC decreases with
distance.
I2C DATA
I2C SDA
IN
I2C SDA
OUT
I2C CLK
DEVICE ADDRESS
START
For more information about the I2C standard, please consult
the Philips™ I2C specification documents.
REGISTER ADDRESS
W A
A6 A5 A4 A3 A2 A1 A0 W A R7 R6 R5 R4 R3 R2 R1 R0 A
A
SDA DRIVEN BY MASTER
1
2
3
4
5
6
7
8
9
A
SDA DRIVEN BY MASTER
1
2
3
4
5
6
DEVICE ADDRESS
STOP START
7
8
9
A6 A5 A4 A3 A2 A1 A0 W
SDA DRIVEN BY MASTER
1
2
3
4
5
6
DATA BYTE0
A
SDA DRIVEN BY ISL29015
A
A D7 D6 D5 D4 D3 D2 D1 D0
7
8
9
1
2
3
4
5
6
7
8
9
FIGURE 1. I2C READ TIMING DIAGRAM SAMPLE
5
FN6522.0
October 31, 2008
ISL29015
START
DEVICE ADDRESS
W
A
W
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
REGISTER ADDRESS
A
FUNCTIONS
STOP
I2C DATA
I2C SDA IN
A6 A5 A4 A3 A2 A1 A0
A
I2C SDA OUT
SDA DRIVEN BY MASTER
A
I2C CLK IN
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
FIGURE 2. I2C WRITE TIMING DIAGRAM SAMPLE
Register Set
There are four registers that are available in the ISL29015. Table 1 summarizes their functions.
TABLE 1. REGISTER SET
BIT
ADDR
REG NAME
7
6
5
4
3
2
1
0
DEFAULT
00h
COMMANDI
OP2
OP1
OP0
0
0
0
0
0
00h
01h
COMMANDII
IS1
IS0
FREQ1
FREQ0
RES1
RES0
RANGE1
RANGE0
00h
02h
DATALSB
D7
D6
D5
D4
D3
D2
D1
D0
00h
03h
DATAMSB
D15
D14
D13
D12
D11
D10
D9
D8
00h
Command Register I 00(hex)
The first command register has the following functions:
1. Operation Mode: Bits 7, 6, and 5.These three bits
determines the operation mode of the device.
TABLE 2. OPERATION MODE
BITS 7 TO 5
000
001
OPERATION
Power-down the device
ALS once
010
IR once
011
Proximity once
For example, the device sources 100mA out of the IRDR
pin if Bits 7 and 6 are 0 during proximity sensing.
TABLE 3. CURRENT SOURCE CAPABILITY AT IRDR PIN
BITS 7: 6
IRDR PIN SOURCE CURRENT
00
100mA IR LED driver
01
50mA IR LED driver
10
25mA IR LED driver
11
12.5mA IR LED driver
2. Modulation Frequency: Bits 5 and 4. These two bits set
the IR LED driver’s modulation frequency.
100
Reserved
101
ALS continuous
110
IR continuous
111
Proximity continuous
TABLE 4. MODULATION FREQUENCY
BITS 5:4
MODULATION FREQUENCY
(kHz)
00
DC
01
N/A
Command Register II 01(hex)
10
N/A
The second command register has the following functions:
11
360
2. Bit 4 to 0 has been reserved to 0.
1. Amplitude of IR driver current: Bits 7 and 6. This device
provides current source to drive an external IR LED. The
drive capability can be programmed through Bits 7 and 6.
6
3. Resolution: Bits 3 and 2. Bits 3 and 2 determine the
ADC’s resolution and the number of clock cycles per
conversion in Internal Timing Mode. 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
FN6522.0
October 31, 2008
ISL29015
(A/D) converter samples the photodiode current signal for
a measurement.
.
TABLE 5. RESOLUTION/WIDTH
BITS 3:2
NUMBER OF CLOCK CYCLES
The transfer function used for n-bit ADC becomes:
n-BIT ADC
00
216 = 65,536
16
01
212 = 4,096
12
10
28 = 256
8
11
24 = 16
4
4. Range: Bits 1 and 0. The Full Scale Range (FSR) can be
adjusted via I2C using Bits 1 and 0. Table 6 lists the
possible values of FSR for the 499kΩ REXT resistor.
TABLE 6. RANGE/FSR LUX
BITS
1:0
k
Here, Range(k) is defined in Table 6. Countmax is the
maximum output counts from the ADC.
RANGE(k)
FSR (LUX) @
ALS SENSING
FSR @ IR
SENSING
Range ( k )
E cal = --------------------------- × DATA
n
2
(EQ. 3)
Here, n = 4, 8, 12 or 16. This is the number of ADC bits
programmed in the command register. 2n represents the
maximum number of counts possible from the ADC output.
Data is the ADC output stored in the data registers (02 hex
and 03 hex).
Integration and Conversion Time
The ADC resolution and fOSC determines the integration
time, tint.
R EXT
n
n
1
t int = 2 × -------------- = 2 × ---------------------------------------------725kHz × 499kΩ
f OSC
(EQ. 4)
00
1
Range1
1,000
Refer to page 3
01
2
Range2
4,000
Refer to page 3
10
3
Range3
16,000
Refer to page 3
where n is the number of bits of resolution and n = 4, 8, 12 or
16. 2n, therefore, is the number of clock cycles. n can be
programmed at the command register 01(hex) bits 3 and 2.
11
4
Range4
64,000
Refer to page 3
TABLE 8. INTEGRATION TIME OF n-BIT ADC
Data Registers (02 hex and 03 hex)
The device has two 8-bit read-only registers to hold the data
from LSB to MSB for ADC. The most significant bit (MSB) is
accessed at 03 hex, and the least significant bit (LSB) is
accessed at 02 hex. For 16-bit resolution, the data is from
D0 to D15; for 12-bit resolution, the data is from D0 to D11;
for 8-bit resolution, the data is from D0 to D7. The registers
are refreshed after every conversion cycle.
TABLE 7. DATA REGISTERS
ADDRESS
(hex)
CONTENTS
02
D0 is LSB for 4, 8, 12 or 16-bit resolution, D3 is MSB
for 4-bit resolution, D7 is MSB for 8-bit resolution
03
D15 is MSB for 16-bit resolution, D11 is MSB for
12-bit resolution
Calculating Lux
The ISL29015’s ADC output codes, DATA, are directly
proportional to lux in the ambient light sensing.
(EQ. 1)
E cal = α × DATA
Here, Ecal is the calculated lux reading. The constant α is
determined by the Full Scale Range and the ADC’s
maximum output counts. The constant is independent on the
light sources (fluorescent, incandescent and sunlight)
because of the light sources’ IR component is removed
during the light signal process. The constant can also be
viewed as the sensitivity: the smallest lux measurement the
device can measure is shown in Equation 2.
Range ( k )
α = ---------------------------Count max
(EQ. 2)
7
REXT
(kΩ)
n = 16-BIT
n = 12-BIT
n = 8-BIT
n = 4-BIT
250
45ms
2.812ms
175.5µs
10.8µs
499**
90ms
5.63ms
351µs
21.6µs
**Recommended REXT resistor value
External Scaling Resistor REXT for fOSC and
Range
The ISL29015 uses an external resistor REXT to fix its
internal oscillator frequency, fOSC and the light sensing
range. fOSC and Range are inversely proportional to REXT.
For user simplicity, the proportionality constant is referenced
to 499kΩ:
499kΩ
Range = ------------------ × Range ( k )
R EXT
(EQ. 5)
499kΩ
f OSC = ------------------ × 725 kHz
R EXT
(EQ. 6)
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 conversion rate. 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.
ADC Output in IR Sensing
The ISL29015’s ADC output codes, DATA, are directly
proportional to the IR intensity received in the IR sensing
phase.
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ISL29015
DATA IR = β × E IR
(EQ. 7)
Here, EIR is the received IR intensity. The constant β
changes with the spectrum of background IR noise like
sunlight and incandescent light. The β also changes with the
ADC’s range and resolution selections.
during the entire operation cycle that includes ALS, IR
sensing and Proximity sensing three different serial phases,
the detection occurs once every 30ms, the average current
consumption including external IR LED drive current can be
calculated from Equation 9:
[ ( 0.05mA + 0.05mA + 1mA + (50mA∗ 50%))∗ 0.4ms ) ]/30ms = 0.35mA
(EQ. 9)
ADC Output in Proximity Sensing
In the proximity sensing, the ADC output codes, DATA, are
directly proportional to the total IR intensity from the
background IR noise and from the IR LED driven by the
ISL29015.
If at a 12-bit ADC resolution where the integration time for
each serial phase becomes 7ms and the total detection time
becomes 100ms, the average current can be calculated from
Equation 10:
DATA PROX = β × E IR + γ × E LED
[ ( 0.05mA + 0.05mA + 1mA + (50mA∗ 50%))∗ 7 ms ) ]/100ms = 1.83mA
(EQ. 8)
β and EIR in Equation 8 have the same meanings as in
Equation 7. The constant γ depends on the spectrum of the
used IR LED and the ADC’s range and resolution selections.
ELED is the IR intensity which is emitted from the IR LED
and reflected by a specific objector to the ISL29015. ELED
depends on the current to the IR LED and the surface of the
object. ELED decreases with the square of the distance
between the object and the sensor.
If background IR noise is small, i.e., EIR can be neglected,
the ADC output directly decreases with the distance. If there
is significant background IR noise, the sequence of the
proximity sensing followed by the IR sensing can be
implemented. The differential reading of ADC outputs from
the proximity and IR sensing has no effect of background
IR noise and directly decreases with the distance between
the object and the sensor. Please refer to “Typical
Performance Curves” on page 10 for ADC output vs
distance. Figure 9 shows ISL29015 configured at 12-bit ADC
resolution, 12.5mA external LED current at 327.7KHz
modulation frequency, detects three different sensing
objects: 92% brightness paper, 18% gray card and ESD
black foam. Figure 10 shows ISL29015 configured at 12-bit
ADC resolution, programmed external LED at 327.7KHz
modulation frequency, detects the same sensing object: 18%
gray card under four different external LED current: 12.5mA,
25mA, 50mA and 100mA to compare the proximity readout
versus distance.
Current Consumption Estimation
The low power operation is achieved through sequential
readout in the serial fashion, as shown in Figure 3, the
device requires three different phases in serial during the
entire detection cycle to do ambient light sensing, infrared
sensing and proximity sensing. The external IR LED will only
be turned on during the proximity sensing phase under user
program controlled current at modulated frequency depends
on user selections. Figure 3 also shows the current
consumption during each ALS, IR sensing and Proximity
sensing phase. For example, at 8-bit ADC resolution the
integration time is 0.4ms. If user programed 50mA current to
supply external IR LED at 327.7kHz modulated frequency,
8
(EQ. 10)
Suggested PCB Footprint
It is important that the users check the “Surface Mount
Assembly Guidelines for Optical Dual FlatPack No Lead
(ODFN) Package” before starting ODFN product board
mounting.
http://www.intersil.com/data/tb/tb477.pdf
Layout Considerations
The ISL29015 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.
Route the supply and I2C traces as far as possible from all
sources of noise. Use two power-supply decoupling
capacitors, 1µF and 0.1µF, placed close to the device.
Typical Circuit
A typical application for the ISL29015 is shown in Figure 4.
The ISL29015’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.
Soldering Considerations
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.
FN6522.0
October 31, 2008
ISL29015
30ms
1µs
ALS
50µA
0.4ms
IR
50µA
0.4ms
PROXIMITY
0.4ms
1mA
IR LED
50mA
327.7 kHz
FIGURE 3. CURRENT CONSUMPTION FOR EACH INTEGRATION PHASE AND DETECTION CYCLE
1.7V TO 3.63V
R1
10kΩ
I2C MASTER
R2
10kΩ
MICROCONTROLLER
SDA
SCL
2.25V TO 3.3V
I2C SLAVE_0
1
2
C1
1µF
C2
0.1µF
3
VDD
IRDR
GND
SDA
REXT
SCL
I2C SLAVE_1
6
5
I2C SLAVE_n
SDA
SDA
SCL
SCL
4
REXT ISL29015
499kΩ
FIGURE 4. ISL29015 TYPICAL CIRCUIT
9
FN6522.0
October 31, 2008
ISL29015
Typical Performance Curves
VDD = 3V, Rext = 499kΩ
1.2
1.2
0.8
NORMALIZED RESPONSE
INCANDESCENT
1.0
HALOGEN
0.6
FLUORESCENT
0.4
AMBIENT
LIGHT
SENSING
1
0.2
HUMAN EYE RESPONSE
IR AND
PROXIMITY
SENSING
0.8
0.6
0.4
0.2
0
400
500
600
700
800
WAVELENGTH (nm)
900
1000
RADIATION PATTERN
20°
10°
0°
10°
20°
30°
40°
50°
50°
60°
60°
70°
70°
80°
80°
90°
0.2 0.4
0.6 0.8
RELATIVE SENSITIVITY
400
500
600
700
800
900
WAVELENGTH (nm)
1000
1100
FIGURE 6. SPECTRAL RESPONSE FOR AMBIENT LIGHT
SENSING AND PROXIMITY SENSING
FIGURE 5. SPECTRUM OF FOUR LIGHT SOURCES
LUMINOSITY
30°
ANGLE 40°
-0.2
300
1100
90°
1.0
1000
65535
VDD = 3V
RANGE = 1000 LUX
16-BIT ADC
900
800
700
INCANDESCENT
HALOGEN
600
500
32768
400
FLUORESCENT
300
200
Ecal =
100
0
0
1000 LUX
216
ADC OUTPUT (COUNT)
0
300
CALCULATED ALS READING (LUX)
NORMALIZED LIGHT INTENSITY
SUN
x DATA
0
100 200 300 400 500 600 700 800 900 1000
LUX METER READING (LUX)
FIGURE 7. RADIATION PATTERN
FIGURE 8. SENSITIVITY TO FOUR LIGHT SOURCES
4500
DATAPROX-DATAIR (COUNT)
10000
DATAPROX-DATAIR
92% BRIGHTNESS PAPER
1000
18% GRAY CARD
100
10
ESD BLACK FOAM
1
0
20
40
60
DISTANCE (mm)
80
100
FIGURE 9. ADC OUTPUT vs DISTANCE WITH DIFFERENT
OBJECTS IN PROXIMITY SENSING
10
4000
3500
IIRLED = 100mA
3000
IIRLED = 50mA
IIRLED = 25mA
2500
IIRLED = 12.5mA
2000
1500
1000
500
0
0
10
20
30
40
50
60
DISTANCE (mm)
70
80
90
FIGURE 10. ADC OUTPUT vs DISTANCE WITH DIFFERENT
LED CURRENT AMPLITUDES IN PROXIMITY
SENSING
FN6522.0
October 31, 2008
ISL29015
Typical Performance Curves
VDD = 3V, Rext = 499kΩ (Continued)
OUTPUT CODE RATIO (FROM +30°C)
OUTPUT CODE (COUNTS)
10
8
6
4
2
0
-60
-20
20
60
100
1.10
300 Lux FLUORESCENT LIGHT
ALS SENSING
1.05
1.00
0.95
0.90
-60
-20
20
TEMPERATURE (°C)
FIGURE 11. OUTPUT CODE FOR 0 LUX vs TEMPERATURE
90
PROXIMITY SENSING
IS<1:0> = 0
SUPPLY CURRENT (µA)
IRDR OUTPUT CURRENT (mA)
100
FIGURE 12. OUTPUT CODE vs TEMPERATURE
105.0
104.5
60
TEMPERATURE (°C)
104.0
103.5
103.0
102.5
102.0
101.5
101.0
85
ALS SENSING
10,000 Lux
80
75
70
65
100.5
100.0
-40
-20
0
20
40
60
TEMPERATURE (°C)
80
100
FIGURE 13. OUTPUT CURRENT vs TEMPERATURE IN
PROXIMITY SENSING
11
120
60
-40
-20
0
20
40
60
TEMPERATURE (°C)
80
100
120
FIGURE 14. SUPPLY CURRENT vs TEMPERATURE IN ALS
SENSING
FN6522.0
October 31, 2008
ISL29015
FIGURE 15. 6 LD ODFN SENSOR LOCATION OUTLINE
For additional products, see www.intersil.com/en/products.html
Intersil products are manufactured, assembled and tested utilizing ISO9000 quality systems as noted
in the quality certifications found at www.intersil.com/en/support/qualandreliability.html
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
12
FN6522.0
October 31, 2008
ISL29015
Package Outline Drawing
L6.2x2.1
6 LEAD OPTICAL DUAL FLAT NO-LEAD PLASTIC PACKAGE (ODFN)
Rev 0, 9/06
2.10
A
6
PIN 1
INDEX AREA
B
1
6
PIN 1
INDEX AREA
0.65
2.00
(4X)
1. 30 REF
1. 35
0.10
6X 0. 30 ± 0. 05
0. 65
TOP VIEW
0.10 M C A B
6X 0. 35 ± 0. 05
BOTTOM VIEW
(0. 65)
MAX 0.75
SEE DETAIL "X"
0.10 C
(0. 65)
(1. 35)
C
BASE PLANE
(6X 0. 30)
SEATING PLANE
0.08 C
SIDE VIEW
(6X 0. 55)
C
0. 2 REF
5
(1. 95)
0 . 00 MIN.
0. 05 MAX.
DETAIL "X"
TYPICAL RECOMMENDED LAND PATTERN
NOTES:
1. Dimensions are in millimeters.
Dimensions in () for Reference Only.
2. Dimensioning and tolerancing conform to AMSE Y14.5m-1994.
3. Unless otherwise specified, tolerance: Decimal ± 0.05
4. Dimension b 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.
13
FN6522.0
October 31, 2008
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