DATASHEET

Proximity Sensor with Intelligent Interrupt and Sleep Modes
ISL29027
Features
The ISL29027 is an integrated infrared light-to-digital converter
with a built-in IR LED driver and I2C Interface (SMBus Compatible).
The flexible interrupt scheme is designed for minimal
microcontroller utilization.
• Works Under All Light Sources Including Sunlight
For proximity sensor (Prox) data conversions, the built-in driver turns
on an external infrared LED and the proximity sensor ADC converts
the reflected IR intensity to digital. This ADC rejects ambient IR noise
(such as sunlight) and has a 540μs conversion time.
• Proximity Sensor with Broad IR Spectrum
- Can Use 850nm and 950nm External IR LEDs
• IR LED Driver with I2C Programmable Sink Currents
- Net 100μs Pulse with 110mA or 220mA Amplitudes
- Periodic Sleep Time up to 800ms Between Pulses
• Ambient IR Noise Cancellation (Including Sunlight)
Intelligent and Flexible Interrupts
• Intelligent Interrupt Scheme Simplifies μC Code
Proximity Sensing
The ISL29027 provides proximity sensing with a typical 138μA
normal operation current (110μA for sensors and internal circuitry,
~28μA for external LED) with 220mA current pulses for a net 100μs,
repeating every 800ms (or under).
• Proximity Interrupt Thresholds
• Adjustable Interrupt Persistency
- 1/4/8/16 Consecutive Triggers Required Before Interrupt
Ultra Low Power
The ISL29027 uses both a hardware pin and software bits to
indicate an interrupt event has occurred. A proximity interrupt is
defined as a measurement over a threshold limit. The user may
also require that proximity interrupts occur at once, up to 16
times in a row before activating the interrupt pin.
• 138μA DC Typical Supply Current for Prox Sensing
- 110μA for Sensors and Internal Circuitry
- 28μA Typical Current for External IR LED (Assuming 220mA
for 100μs Every 800ms)
• <1.0μA Supply Current When Powered Down
Easy to Use
The ISL29027 is designed to operate from 2.25V to 3.63V over the
-40°C to +85°C ambient temperature range. It is packaged in a
clear, lead-free 8 lead ODFN package.
Applications
- Mobile Devices: Smart Phone, PDA, GPS
- Computing Devices: Laptop PC, Netbook
- Consumer Devices: LCD-TV, Digital Picture Frame, Digital
Camera
• Set Registers; Wait for Interrupt
• I2C (SMBus Compatible) Output
• Temperature Compensated
• Tiny ODFN8 2.0x2.1x0.7 (mm) Package
Additional Features
• 1.7V to 3.63V Supply for I2C Interface
• 2.25V to 3.63V Sensor Power Supply
• Pb-Free (RoHS Compliant)
• I2C Address Selection Pin
2
COMMAND
REGISTER
LIGHT DATA
PROCESS
IR
CHANNEL
ADC
DATA
REGISTER
1
ADDR0
5
SCL
6
SDA
INTERRUPT
7
INT
IR DRIVER
8
IRDR
I2C
IR PHOTODIODE
ARRAY
IREF
FOSC
4
3
REXT
GND
FIGURE 1. BLOCK DIAGRAM
February 2, 2012
FN7815.1
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 2011, 2012. 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.
ISL29027
Pin Configuration
Pin Descriptions
ISL29027
8 LD ODFN (2.0mmx2.1mmx0.7mm)
TOP VIEW
ADDR0
1
VDD
2
GND
3
REXT
4
THERMAL
PAD
8
IRDR
7
INT
6
SDA
5
SCL
*THERMAL PAD CAN BE CONNECTED TO GND OR
ELECTRICALLY ISOLATED
PIN
NUMBER
PIN
NAME
0
T.PAD
1
ADDR0
I2C address pin - pull high or low
(do not float)
2
VDD
Positive supply: 2.25V to 3.63V
3
GND
Ground
4
REXT
External resistor (499kΩ; 1%) connects this
pin to ground
5
SCL
6
SDA
I2C clock line The I2C bus lines can be pulled
from 1.7V to above VDD, 3.63V
I2C data line max
7
INT
8
IRDR
DESCRIPTION
Thermal Pad (connect to GND or float)
Interrupt pin; Logic output
(open-drain) for interrupt
IR LED driver pin - current flows into ISL29027
from LED cathode
Ordering Information
PART NUMBER
(Notes 1, 2, 3)
TEMP. RANGE
(°C)
ISL29027IROZ-T7
-40 to +85
PACKAGE
Tape & Reel
(Pb-free)
8 Ld ODFN
PKG.
DWG. #
L8.2.1x2.0
NOTES:
1. Please refer to TB347 for details on reel specifications.
2. 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.
3. For Moisture Sensitivity Level (MSL), please see device information page for ISL29027. For more information on MSL, please see Technical Brief
TB477.
2
FN7815.1
February 2, 2012
ISL29027
Absolute Maximum Ratings (TA = +25°C)
Thermal Information
VDD Supply Voltage between VDD and GND . . . . . . . . . . . . . . . . . . . . . .4.0V
I2C Bus Pin Voltage (SCL, SDA). . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to 4.0V
I2C Bus Pin Current (SCL, SDA). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <10mA
REXT Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-0.5V to VDD + 0.5V
IRDR Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.5V
ADDR0 Pin Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-0.5V to VDD + 0.5V
INT Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to 4.0V
INT Pin Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <10mA
ESD Rating
Human Body Model (Note 6). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2kV
Thermal Resistance (Typical)
θJA (°C/W) θJC (°C/W)
8 Ld ODFN Package (Notes 4, 5) . . . . . . . .
88
10
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.
NOTES:
4. 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.
5. For θJC, the “case temp” location is the center of the exposed metal pad on the package underside.
6. ESD on all pins is 2kV except for IRDR, which is 1.5kV.
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
VDD = 3.0V, TA = +25°C, REXT = 499kΩ 1% tolerance.
DESCRIPTION
CONDITION
Power Supply Range
MIN
MAX
(Note 9) TYP (Note 9) UNIT
2.25
3.0
3.63
V
SR_VDD
Input Power-up Slew Rate
VDD Rising Edge between 0.4V and 2.25V
IDD_OFF
Supply Current when Powered Down
PROX_EN = 0
0.1
PROX_EN = 1
80
µA
Internal Oscillator Frequency
5.25
MHz
tINTGR_PROX
8-bit Prox Integration/Conversion Time
0.54
ms
DATAPROX_0
Prox Measurement w/o Object in Path
1
DATAPROX_F
Full Scale Prox ADC Code
DATAPROX_1
Prox Measurement Result
(Note 7)
tr
Rise Time for IRDR Sink Current
RLOAD = 15Ω at IRDR pin, 20% to 80%
500
ns
tf
Fall time for IRDR Sink Current
RLOAD = 15Ω at IRDR pin, 80% to 20%
500
ns
IIRDR_0
IRDR Sink Current
PROX_DR = 0; VIRDR = 0.5V
IIRDR_1
IRDR Sink Current
PROX_DR = 1; VIRDR = 0.5V
IRDR Leakage Current
PROX_EN = 0; VDD = 3.63V (Note 8)
VIRDR
Acceptable Voltage Range on IRDR Pin
Register bit PROX_DR = 0
tPULSE
Net IIRDR On Time Per PROX Reading
100
µs
VREF
Voltage of REXT Pin
0.51
V
FI2C
I2C Clock Rate Range
VI2C
Supply Voltage Range for I2C Interface
IDD_PRX_SLP Supply Current for Prox in Sleep Time
fOSC
IIRDR_LEAK
0.5
36
95
V/ms
46
110
0.8
2
Counts
255
Counts
56
Counts
125
220
0.001
0.5
1.7
µA
mA
mA
1
µA
4.3
V
400
kHz
3.63
V
0.55
V
VIL
SCL and SDA Input Low Voltage
VIH
SCL and SDA Input High Voltage
ISDA
SDA Current Sinking Capability
VOL = 0.4V
3
5
mA
IINT
INT Current Sinking Capability
VOL = 0.4V
3
5
mA
3
1.25
V
FN7815.1
February 2, 2012
ISL29027
Electrical Specifications
PARAMETER
PSRRIRDR
VDD = 3.0V, TA = +25°C, REXT = 499kΩ 1% tolerance. (Continued)
DESCRIPTION
(ΔIIRDR)/(ΔVIRDR)
CONDITION
MIN
MAX
(Note 9) TYP (Note 9) UNIT
PROX_DR = 0; VIRDR = 0.5V to 4.3V
4
mA/V
NOTES:
7. An 850nm infrared LED is used to test PROX/IR sensitivity in an internal test mode.
8. Ability to guarantee IIRDR leakage of ~1nA is limited by test hardware..
9. Compliance to datasheet limits is assured by one or more methods: production test, characterization and/or design.
I2C Electrical Specifications
(Note 10).
PARAMETER
For SCL and SDA unless otherwise noted, VDD = 3V, TA = +25°C, REXT = 499kΩ 1% tolerance
DESCRIPTION
CONDITION
MIN
TYP
MAX
UNIT
3.63
V
VI2C
Supply Voltage Range for I2C Interface
fSCL
SCL Clock Frequency
400
kHz
VIL
SCL and SDA Input Low Voltage
0.55
V
VIH
SCL and SDA Input High Voltage
Vhys
Hysteresis of Schmitt Trigger Input
VOL
Low-level Output Voltage (Open-drain) at 4mA Sink
Current
Ii
1.7
Input Leakage for each SDA, SCL Pin
1.25
V
0.05VDD
V
-10
0.4
V
10
µA
tSP
Pulse Width of Spikes that must be Suppressed by
the Input Filter
50
ns
tAA
SCL Falling Edge to SDA Output Data Valid
900
ns
Ci
Capacitance for each SDA and SCL Pin
10
pF
tHD:STA
Hold Time (Repeated) START Condition
After this period, the first clock pulse is
generated
600
ns
tLOW
LOW Period of the SCL Clock
Measured at the 30% of VDD crossing
1300
ns
tHIGH
HIGH period of the SCL Clock
600
ns
tSU:STA
Set-up Time for a Repeated START Condition
600
ns
tHD:DAT
Data Hold Time
30
ns
tSU:DAT
Data Set-up Time
100
ns
tR
Rise Time of both SDA and SCL Signals
(Note 11)
20 + 0.1xCb
ns
tF
Fall Time of both SDA and SCL Signals
(Note 11)
20 + 0.1xCb
ns
Set-up Time for STOP Condition
600
ns
Bus Free Time Between a STOP and START
Condition
1300
ns
tSU:STO
tBUF
Cb
Capacitive Load for Each Bus Line
400
Maximum is determined by tR and tF
1
pF
Rpull-up
SDA and SCL System Bus Pull-up Resistor
kΩ
tVD;DAT
Data Valid Time
0.9
µs
tVD:ACK
Data Valid Acknowledge Time
0.9
µs
VnL
Noise Margin at the LOW Level
0.1VDD
V
VnH
Noise Margin at the HIGH Level
0.2VDD
V
NOTES:
10. All parameters in I2C Electrical Specifications table are guaranteed by design and simulation.
11. Cb is the capacitance of the bus in pF.
4
FN7815.1
February 2, 2012
ISL29027
FIGURE 2. I2C TIMING DIAGRAM
Register Map
There are ten 8-bit registers accessible via I2C. Registers 0x1 and
0x2 define the operation mode of the device. Registers 0x3 and 0x4
store the various Prox thresholds which trigger interrupt events.
Registers 0x8 store the results of Prox ADC conversions.
TABLE 1. ISL29028A REGISTERS AND REGISTER BITS
BIT
ADDR
REG NAME
7
6
0x00
(n/a)
0x01
CONFIGURE
PROX EN
0x02
INTERRUPT
PROX_FLAG
5
4
3
2
1
0
(Reserved)
PROX_SLP[2:0]
PROX_PRST[1:0]
PROX_DR
(Write 0)
(Write0)
DEFAULT
(n/a)
(Write 0)
(Write0)
(Write 0)
(Write0)
0x00
(Write 0)
0x00
0x03
PROX_LT
PROX_LT[7:0]
0x00
0x04
PROX_HT
PROX_HT[7:0]
0xFF
0x05
(n/a)
(Reserved)
(n/a)
0x06
(n/a)
(Reserved)
(n/a)
0x07
(n/a)
(Reserved)
(n/a)
0x08
PROX_DATA
PROX_DATA[7:0]
0x00
0x09
(n/a)
(Reserved)
(n/a)
0x0A
(n/a)
(Reserved)
(n/a)
0x0E
TEST1
(Write as 0x00)
0x00
0x0F
TEST2
(Write as 0x00)
0x00
5
FN7815.1
February 2, 2012
ISL29027
Register Descriptions
TABLE 2. REGISTER 0x00 (RESERVED)
BIT #
ACCESS
DEFAULT
NAME
7:0
RO
(n/a)
(n/a)
FUNCTION/OPERATION
Reserved - no need to read or write
TABLE 3. REGISTER 0x01 (CONFIGURE) - PROX CONFIGURATION
BIT #
ACCESS
DEFAULT
NAME
FUNCTION/OPERATION
7
RW
0x00
PROX_EN
(Prox Enable)
When = 0, proximity sensing is disabled
When = 1, continuous proximity sensing is enabled. Prox data will be ready 0.54ms after this
bit is set high
6:4
RW
0x00
PROX_SLP
(Prox Sleep)
For bits 6:4 = (see the following)
111; sleep time between prox IR LED pulses is 0.0ms (run continuously)
110; sleep time between prox IR LED pulses is 12.5ms
101; sleep time between prox IR LED pulses is 50ms
100; sleep time between prox IR LED pulses is 75ms
011; sleep time between prox IR LED pulses is 100ms
010; sleep time between prox IR LED pulses is 200ms
001; sleep time between prox IR LED pulses is 400ms
000; sleep time between prox IR LED pulses is 800ms
3
RW
0x00
PROX_DR
(Prox Drive)
When = 0, IRDR behaves as a pulsed 110mA current sink
When = 1, IRDR behaves as a pulsed 220mA current sink
2
RW
0x00
Unused
(Write 0)
Unused register bit (write 0)
1
RW
0x00
Unused
(Write 0)
Unused register bit (write 0)
0
RW
0x00
Unused
(Write 0)
Unused register bit (write 0)
TABLE 4. REGISTER 0x02 (INTERRUPT) - PROX INTERRUPT CONTROL
BIT #
7
ACCESS
FLAG
DEFAULT
BIT NAME
0x00
PROX_FLAG
(Prox Flag)
When = 0, no Prox interrupt event has occurred since power-on or last “clear”
When = 1, a Prox interrupt event occurred. Clearable by writing “0”
FUNCTION/OPERATION
For bits 6:5 = (see the following)
00; set PROX_FLAG if 1 conversion result trips the threshold value
01; set PROX_FLAG if 4 conversion results trip the threshold value
10; set PROX_FLAG if 8 conversion results trip the threshold value
11; set PROX_FLAG if 16 conversion results trip the threshold value
6:5
RW
0x00
PROX_PRST
(Prox Persist)
4
RW
0x00
Unused
(Write 0)
Unused register bit - write 0
3
RW
0x00
Unused
(Write 0)
Unused register bit - write 0
RW
0x00
Unused
(Write 0)
Unused register bit - write 0
2:1
RW
0x00
Unused
(Write 0)
Unused register bit - write 0
0
TABLE 5. REGISTER 0x03 (PROX_LT) - INTERRUPT LOW THRESHOLD FOR PROXIMITY SENSOR
BIT #
ACCESS
7:0
RW
6
DEFAULT
BIT NAME
0x00
PROX_LT
(Prox Threshold)
FUNCTION/OPERATION
8-bit interrupt low threshold for
proximity sensing
FN7815.1
February 2, 2012
ISL29027
TABLE 6. REGISTER 0x04 (PROX_HT) - INTERRUPT HIGH THRESHOLD FOR PROXIMITY SENSOR
BIT #
ACCESS
DEFAULT
BIT NAME
FUNCTION/OPERATION
7:0
RW
0xFF
PROX_HT
(Prox Threshold)
8-bit interrupt high threshold for proximity sensing
TABLE 7. REGISTER 0x08 (PROX_DATA) - PROXIMITY SENSOR DATA
BIT #
ACCESS
DEFAULT
BIT NAME
FUNCTION/OPERATION
7:0
RO
0x00
PROX_DATA
(Proximity Data)
Results of 8-bit proximity sensor ADC conversion
TABLE 8. REGISTER 0x0E (TEST1) - TEST MODE
BIT #
ACCESS
DEFAULT
BIT NAME
FUNCTION/OPERATION
7:0
RW
0x00
(Write as 0x00)
Test mode register. When 0x00, in normal operation
TABLE 9. REGISTER 0x0F (TEST2) - TEST MODE 2
BIT #
ACCESS
DEFAULT
BIT NAME
7:0
RW
0x00
(Write as 0x00)
I2C DATA
DEVICE ADDRESS
START
I2C SDA
MASTER
Test mode register. When 0x00, in normal operation
REGISTER ADDRESS
W 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
A6 A5 A4 A3 A2 A1 A0 W A R7 R6 R5 R4 R3 R2 R1 R0 A
I2C SDA
SLAVE (ISL29027)
I2C CLK
FUNCTION/OPERATION
7
8
A6 A5 A4 A3 A2 A1 A0 W
SDA DRIVEN BY MASTER
1
9
2
3
4
5
DATA BYTE0
A
SDA DRIVEN BY ISL29027
A
A D7 D6 D5 D4 D3 D2 D1 D0
6
7
8
9
1
2
3
4
5
6
7
8
9
FIGURE 3. I2C DRIVER TIMING DIAGRAM FOR MASTER AND SLAVE CONNECTED TO COMMON BUS
Principles of Operation
I2C Interface
The ISL29027’s I2C interface slave address is internally hardwired
as 0b100010<x>, where “0b” signifies binary notation and x
represents the logic level on pin ADDR0.
Figure 3 shows a sample one-byte read. The I2C bus master
always drives the SCL (clock) line, while either the master or the
slave can drive the SDA (data) line. Every I2C transaction begins
with the master asserting a start condition (SDA falling while SCL
remains high). The first transmitted byte is initiated by the
master and includes 7 address bits and a R/W bit. The slave is
responsible for pulling SDA low during the ACK bit after every
transmitted byte.
Each I2C transaction ends with the master asserting a stop
condition (SDA rising while SCL remains high).
subtracts the IR reading before and after the LED is driven (to
remove ambient IR such as sunlight), and converts this value to a
digital count stored in Register 0x8. Because of the conversion
times, the user must let the ADCs perform one full conversion
first before reading from I2C Registers PROX_DATA (wait
0.54ms). The proximity sensor runs continuously with a time
between conversions decided by PROX_SLP (Register 1 Bits
[6:4]).(as shown in Figure 4).
PROX
SENSOR
ACTIVE
IRDR
(CURRENT
DRIVER)
0.54m s FOR
PROX
CONVERSION
TIME
SERIES OF
CURRENT
PULSES
TOTALING 0.1ms
TIME
For more information about the I2C standard, please consult the
Philips™ I2C specification documents.
Photodiodes and ADCs
The ISL29027 contains photodiode arrays which convert photons
(light) into current. The proximity sensor is an 8-bit ADC. When
proximity sensing is enabled, the IRDR pin will drive a usersupplied infrared LED, the emitted IR reflects off an object (i.e., a
human head) back into the ISL29027, and a sensor converts the
reflected IR wave to a current signal in 0.54ms. The ADC
7
SLEEP TIME
(PROX_SLP)
FIGURE 4. CURRENT DRIVE MODE OPTIONS
Proximity Sensing
When proximity sensing is enabled (PROX_EN = 1), the external
IR LED is driven for 0.1ms by the built-in IR LED driver through
the IRDR pin. The amplitude of the IR LED current depends on
Register 1 bit 3: PROX_DR. If this bit is low, the load will see a
FN7815.1
February 2, 2012
ISL29027
fixed 110mA current pulse. If this bit is high, the load on IRDR
will see a fixed 220mA current pulse as seen in Figure 5.
220mA
(PROX_DR = 1)
110mA
(PROX_DR = 0)
PIN 8 - IRDR
(IRDR IS HI-Z WHEN
NOT DRIVING)
FIGURE 5. CURRENT DRIVE MODE OPTIONS
When the IR from the LED reaches an object and gets reflected
back into the ISL29027, the reflected IR light is converted into
current as per the IR spectral response shown in Figure 7. One
entire proximity measurement takes 0.54ms for one conversion
(which includes 0.1ms spent driving the LED), and the period
between proximity measurements is decided by PROX_SLP
(sleep time) in (Register 1 Bits 6:4).
Average LED driving current consumption is given by Equation 1.
I lRDR ;PEAK × 100μs
I lRDR ;AVE = ----------------------------------------------------T SLEEP
(EQ. 1)
Interrupt persistency is another useful option available for
proximity measurements. Persistency requires X-in-a-row
interrupt flags before the INT pin is driven low. Prox have their
own independent interrupt persistency options. See PROX_PRST
bits in Register 2.
VDD Power-up and Power Supply
Considerations
Upon power-up, please ensure a VDD slew rate of 0.5V/ms or
greater. After power-up, or if the user’s power supply temporarily
deviates from our specification (2.25V to 3.63V), Intersil
recommends the user write the following: write 0x00 to register
0x01, write 0x29 to register 0x0F, write 0x00 to register 0x0E,
and write 0x00 to register 0x0F. The user should then wait ~1ms
or more and then rewrite all registers to the desired values. If the
user prefers a hardware reset method instead of writing to test
registers: set VDD = 0V for 1 second or more, power back up at
the required slew rate, and write registers to the desired values.
Power-Down
To put the ISL29027 into a power-down state, the user can set
PROX_EN bits to 0 in Register 1. Or more simply, set all of
Register 1 to 0x00.
Noise Rejection
Total current consumption is the sum of IDD and IIRDR. The IRDR
pin sinks current (as shown in Figure 5) and the average IRDR
current can be calculated using Equation 1. IDD depends on
voltage and the mode-of-operation, as seen in Figure 9.
Charge balancing 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. Since wall sockets
may output at 60Hz or 50Hz, our integration time is 0.54ms: the
lowest common integer number of cycles for both frequencies.
Interrupt Function
Proximity Detection of Various Objects
The ISL29027 has an intelligent interrupt scheme designed to
shift some logic processing away from intensive microcontroller
I2C polling routines (which consume power) and towards a more
independent light sensor, which can instruct a system to “wake
up” or “go to sleep”.
Proximity sensing relies on the amount of IR reflected back from
objects. A perfectly black object would absorb all light and reflect
no photons. The ISL29027 is sensitive enough to detect black ESD
foam which reflects only 1% of IR. For biological objects, blonde
hair reflects more than brown hair and customers may notice that
skin tissue is much more reflective than hair. IR penetrates into
the skin and is reflected or scattered back from within. As a result,
the proximity count peaks at contact and monotonically decreases
as skin moves away. The reflective characteristics of skin are very
different from that of paper.
A typical IRDR scheme is 220mA amplitude pulses every 800ms,
which yields 28μA DC.
Total Current Consumption
A proximity interrupt event (PROX_FLAG) is governed by the high
and low thresholds in registers 3 and 4 (PROX_LT and PROX_HT).
PROX_FLAG is set when the measured proximity data is more
than the higher threshold X-times-in-a-row (X is set by user; see
next paragraph). The proximity interrupt flag is cleared when the
prox data is lower than the low proximity threshold
X-times-in-a-row, or when the user writes “0” to PROX_FLAG.
8
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February 2, 2012
ISL29027
Typical Circuit
Suggested PCB Footprint
A typical application for the ISL29027 is shown in Figure 6. The
ISL29027’s I2C address is internally hardwired as 0b100010<x>,
with x representing the logic state of input I2C address pin
ADDR0. The device can be tied onto a system’s I2C bus together
with other I2C compliant devices.
It is important that users check the “Surface Mount Assembly
Guidelines for Optical Dual FlatPack No Lead (ODFN) Package”
before starting ODFN product board mounting.
Soldering Considerations
Convection heating is recommended for reflow soldering; directinfrared 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.
http://www.intersil.com/data/tb/TB477.pdf
Layout Considerations
The ISL29027 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. 0.1µF and 1µF power supply decoupling
capacitors need to be placed close to the device.
VI2C_PULL-UP
R1
10kΩ
R2
10kΩ
I2C MASTER
R3
10kΩ
MICROCONTROLLER
INT
SDA
SCL
VDD
VIR-LED
SLAVE_0
C2
0.1µF
I2C SLAVE_n
SDA
SDA
7
SCL
SCL
2 VDD
C1
1µF
SLAVE_1
1 ADDR0 IRDR 8
3
4
INT
GND
SDA
REXT
SCL
REXT
499kΩ
6
5
ISL29027
FIGURE 6. ISL29027 TYPICAL CIRCUIT
9
FN7815.1
February 2, 2012
ISL29027
Typical Performance Curves
1.0
300
HUMAN EYE
0.9
PROX
0.8
18% GREY CARD
250
PROX COUNTS (8-BIT)
NORMALIZED RESPONSE
VDD = 3.0V, REXT = 499kΩ
0.7
0.6
0.5
0.4
0.3
0.2
220mA MODE
200
110mA MODE
150
100
WHITE COPY PAPER
50
0.1
0.0
300
0
400
500
600
700
800
900
1000
1100
0
20
40
60
WAVELENGTH (nm)
FIGURE 7. ISL29027 SENSITIVITY TO DIFFERENT WAVELENGTHS
80 100 120
DISTANCE (mm)
140
160
180
200
FIGURE 8. PROX COUNTS vs DISTANCE WITH 10CM x 10CM
REFLECTOR
160
240
120
100
80
PROX (DURING SLEEP MODE)
60
40
2.25 2.40
220mA-MODE (PROX_DR = 1)
220
IIRDR (mA)
MEASURED IDD (µA)
140
200
180
160
140
120
2.55
2.70 2.85 3.00 3.15
INPUT VDD (V)
3.30 3.45 3.60
FIGURE 9. VDD vs IDD FOR VARIOUS MODES OF OPERATION
10
100
110mA-MODE (PROX_DR = 0)
0
0.5
1.0
1.5
2.0
2.5
3.0
VIRDR (V)
3.5
4.0
4.5
5.0
FIGURE 10. IRDR PULSE AMPLITUDE vs VIRDR
FN7815.1
February 2, 2012
ISL29027
2.00
SENSOR OFFSET
2.10
0.43
1
8
2
7
3
6
0.50
4
5
0.42
FIGURE 11. 8 LD ODFN SENSOR LOCATION OUTLINE - DIMENSIONS IN mm
11
FN7815.1
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ISL29027
Revision History
The revision history provided is for informational purposes only and is believed to be accurate, but not warranted. Please go to web to make
sure you have the latest Rev.
DATE
REVISION
CHANGE
2/7/11
FN7815.0
Initial Release.
7/14/11
FN7815.1
Page 1:
Corrected "Light Data Process ALS and IR" to "Light Data Process IR"
Page 2:
Corrected Technical Brief reference in Note 3 from TB363 to TB477
Page 10:
Removed "(USING ISL29028 EVALUATION BOARD)" from Figure 8 caption
Page 13:
Updated L8.2.1x2.0 as follows:
Changed the drawing in the bottom view to show the new look of the pin#1 indicator
Corrected note 4 from "Dimension b applies.." to "Dimension applies..."
Added note 4 callout to bottom view
Enclosed Note #'s 4, 5, 6 in triangles
About Intersil
Intersil Corporation is a leader in the design and manufacture of high-performance analog, mixed-signal and power management
semiconductors. The company's products address some of the largest markets within the industrial and infrastructure, personal
computing and high-end consumer markets. For more information about Intersil, visit our website at www.intersil.com.
For the most updated datasheet, application notes, related documentation and related parts, please see the respective product
information page found at www.intersil.com. You may report errors or suggestions for improving this datasheet by visiting
www.intersil.com/en/support/ask-an-expert.html. Reliability reports are also available from our website at
http://www.intersil.com/en/support/qualandreliability.html#reliability
For additional products, see www.intersil.com/product_tree
Intersil products are manufactured, assembled and tested utilizing ISO9000 quality systems as noted
in the quality certifications found 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
12
FN7815.1
February 2, 2012
ISL29027
Package Outline Drawing
L8.2.1x2.0
8 LEAD OPTICAL DUAL FLAT NO-LEAD PLASTIC PACKAGE (ODFN)
Rev 3, 1/11
2.10
A
6
PIN 1
INDEX AREA
0.15
B
0.25
6
PIN 1
INDEX AREA
0.50
1.50
2.00
1.50
0.20±0.05 4
(2X)
0.10 M C A B
0.10
8X 0 . 35 ± 0 . 05
TOP VIEW
0.75
BOTTOM VIEW
SEE DETAIL "X"
2.50
0.10 C
2.10
0.70±0.05
C
BASE PLANE
SEATING PLANE
0.08 C
SIDE VIEW
(6x0.50)
(1.50)
(8x0.20)
C
(8x0.20)
5
0 . 00 MIN.
0 . 05 MAX.
(8x0.55)
DETAIL "X"
(0.75)
TYPICAL RECOMMENDED LAND PATTERN
0 . 2 REF
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 0.25mm and 0.35mm 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 indentifier may be
either a mold or mark feature.
13
FN7815.1
February 2, 2012
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