ISL29021IROZ-T7 [INTERSIL]
Digital Proximity Sensor with Interrupt Function; 数字接近传感器具有中断功能
| 型号： | ISL29021IROZ-T7 |
| 厂家： | 
Intersil |
| 描述： | Digital Proximity Sensor with Interrupt Function |
| 文件： | 总12页 (文件大小：578K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
ISL29021
®
Data Sheet
March 3, 2009
FN6732.0
Digital Proximity Sensor with Interrupt
Function
Features
Proximity Sensing
• Ambient IR Cancellation During Proximity Sensing
- Works Under Direct Sunlight
The ISL29021 is an integrated proximity and infrared sensor
2
with a built-in IR LED driver and I C Interface (SMBus
Compatible). This device provides infrared sensing to allow
proximity estimation featured with interrupt function.
• IR LED Driver with Programmable Source Current
- Adjustable Current Drive from 100mA to 12.5mA
For infrared and proximity sensing, an internal ADC has
been designed based on the charge-balancing A/D
conversion technique.
• Programmable LED current Modulation Frequency
• Variable Conversion Resolution up to 16-bits
2
• Selectable Range (via I C)
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.
• Works Under Various Light Sources, Including Sunlight
Ideal Spectral Response for Proximity Sensor
• Proximity sensor range from 850nm to 950nm
- Can use either 850nm or 950nm LED solution
Ultra Low Power
• 90μA Max Operating Current
• Software Shutdown and Automatic Shutdown
2
- 0.5μA Max Shutdown Current
Four different modes of operation can be selected via the I C
interface: programmable IR sensing once, programmable
proximity sensing once, 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 0.5µA.
Easy to Use
2
• I C (SMBus Compatible) Output
• No Complex Algorithms Needed
• Temperature Compensated
• Small Form Factor
The ISL29021 supports both hardware and software
- 8 Ld 2.0mmx2.1mmx0.7mm ODFN Package
interrupts that remain asserted until the host clears it through
2
Additional Features
I C interface for proximity detection.
2
• I C and SMBus Compatible
Designed to operate on supplies from 2.5V to 3.63V, the
ISL29021 is specified for operation over the -40°C to +85°C
ambient temperature range. It is packaged in a clear, Pb-free
8 Ld ODFN package.
2
• 1.7V to 3.63V Supply for I C Interface
• 2.25V to 3.63V Sensor Power Supply
• Pb-Free (RoHS compliant)
Ordering Information
Applications
PART NUMBER
(Note)
TEMP. RANGE PACKAGE
PKG.
DWG. #
• Display and Keypad Proximity Sensing for:
- Mobile Devices: Smart Phone, PDA, GPS
- Computing Devices: Notebook PC, Webpad
(°C)
(Pb-Free)
ISL29021IROZ-T7*
-40 to +85
8 Ld ODFN L8.2.1x2.0
ISL29021IROZ-EVALZ Evaluation Board
- Consumer Devices: LCD-TV, Digital Picture Frame, Digital
Camera
*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.
• Industrial and Medical Proximity Sensing
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1
1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright © Intersil Americas Inc. 2009. All Rights Reserved.
All other trademarks mentioned are the property of their respective owners.
ISL29021
Pinout
ISL29021
(8 LD ODFN
TOP VIEW)
VDDD
VDDA
GND
1
8
7
6
5
IRDR
INT
2
3
4
SDA
SCL
REXT
EXPOSED PAD CAN BE CONNECTED TO GND OR
ELECTRICALLY ISOLATED
Pin Descriptions
PIN NUMBER PIN NAME
DESCRIPTION
1
2
3
4
VDDD
VDDA
GND
Positive digital supply: 2.5V to 3.63V.
Positive analog supply: 2.5V to 3.63V, VDDA and VDDD should be externally shorted.
Ground.
REXT
External resistor pin setting the internal reference current and the conversion time. 499kΩ with 1% tolerance resistor
is recommended.
2
2
5
6
7
8
SCL
SDA
INT
I C serial clock line
The I C bus lines can be pulled from 1.7V to above V , 3.63V max.
DD
2
I C serial data line
Interrupt pin; LO for interrupt/alarming. The INT pin is an open drain.
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 I C.
2
Exposed pad connected to ground or electrically isolated.
Block Diagram
VDDA
2
VDDD
1
COMMAND
REGISTER
IR DATA
PROCESS
INTEGRATION
ADC
DATA
REGISTER
SDA
SCL
6
5
2
IR PHOTODIODE
ARRAY
I C
IREF
INTERRUPT
IR DRIVER
INT
7
8
FOSC
IRDR
3
4
REXT
GND
ISL29021
FN6732.0
March 3, 2009
2
ISL29021
Absolute Maximum Ratings (T = +25°C)
Thermal Information
A
V
V
(VDDD,VDDA) Supply Voltage between V
and GND . . . . . .4V
Thermal Resistance (Typical, Note 1)
θ
JA
(°C/W)
88
SUP
DD
and GND . . . . V
Supply Voltage between V
+/- 0.5V
DDA
DDA
DDD
8 Ld ODFN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
I C Bus (SCL, SDA) and INT Pin Voltage . . . . . . . . . . . . -0.2V to 4V
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
2
I C Bus (SCL, SDA) and INT Pin Current . . . . . . . . . . . . . . . <10mA
IRDR Pin Voltage. . . . . . . . . . . . . . . . . . . . . . . .-0.2V to V
+ 0.5V
+ 0.5V
DD
DD
R
Pin Voltage. . . . . . . . . . . . . . . . . . . . . . . .-0.2V to V
EXT
ESD Rating
Human Body Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2kV
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. θ is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See
JA
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: T = T = T
A
J
C
Electrical Specifications
V
) = 3V, T = +25°C, R
= 499kΩ 1% tolerance, 16-bit ADC operation, unless otherwise
EXT
(
,
SUP VDDD VDDA
specified.
A
PARAMETER
DESCRIPTION
CONDITION
MIN
TYP
MAX UNIT
V
Power Supply Range for VDDD, VDDA
Supply Current when Powered Down
Supply Current of IR Sensing
(Note 2)
2.25
3.63
0.5
V
µA
SUP
I
I
Software disabled or auto power-down
0.1
70
SUP(OFF)
90
µA
SUP(ON)
2
2
V
Supply Voltage Range for I C Interface
1.7
3.63
825
V
I C
f
t
Internal Oscillator Frequency
675
750
90
kHz
ms
OSC
ADC Integration/Conversion Time
16-bit ADC data
E = 0 lux
int
2
2
F
I C Clock Rate Range
1 to 400
1
kHz
Counts
I C
DATA_IR0
DATA_FS
DATA_IR1
DATA_IR2
DATA_IR3
DATA_IR4
Count Output When Dark
Full Scale ADC Code
Infrared Count Output
Infrared Count Output
Infrared Count Output
Infrared Count Output
6
65535 Counts
15000 20000 25000 Counts
E = 210 lux, Sunlight (Note 3), IR sensing, Range 1
E = 210 lux, Sunlight (Note 3), IR sensing, Range 2
E = 210 lux, Sunlight (Note 3), IR sensing, Range 3
E = 210 lux, Sunlight (Note 3), IR sensing, Range 4
5000
1250
312
Counts
Counts
Counts
V
V
V
V
Voltage of R
EXT
Pin
0.52
REF
SCL and SDA Input Low Voltage
SCL and SDA Input High Voltage
SDA and INT Current Sinking Capability
IRDR Source Current
0.55
V
IL
1.25
4
V
IH
I
I
I
I
I
I
5
mA
mA
mA
mA
mA
V
SDA, INT
IRDR1
IS<1:0> = 0 (Note 4)
100
50
IRDR Source Current
IS<1:0> = 1 (Note 4)
15Ω at IRDR pin
IS<1:0> = 2 (Note 4)
44
58
IRDR2
IRDR Source Current
25
IRDR3
IRDR Source Current
IS<1:0> = 3 (Note 4)
12.5
IRDR4
V
tr
tf
Voltage Head Room of IRDR Pin
Rise Time for IRDR Source Current
Fall Time for IRDR Source Current
IR LED Modulation Frequency
IR LED Modulation Frequency
V
- 0.6
IRLED
DD
R
R
= 15Ω at IRDR pin, 20% to 80%
= 15Ω at IRDR pin, 80% to 20%
35
10
ns
LOAD
LOAD
ns
f
f
Freq = 0 (Note 4)
Freq = 1 (Note 4)
DC
360
kHz
kHz
IRLED1
IRLED2
FN6732.0
March 3, 2009
3
ISL29021
Electrical Specifications
V
) = 3V, T = +25°C, R = 499kΩ 1% tolerance, 16-bit ADC operation, unless otherwise
SUP VDDD VDDA EXT
(
,
A
specified. (Continued)
DESCRIPTION
Supply Current of Proximity Sensing
PARAMETER
CONDITION
MIN
TYP
101
51
MAX UNIT
I
I
IS<1:0> = 0, Freq = 0 (Note 4)
IS<1:0> = 0, Freq = 1 (Note 4)
mA
mA
%
SUP (IRLED1)
SUP (IRLED2)
Supply Current of Proximity Sensing
Duty Cycle of IR LED Modulation
Duty Cycle
50
PROX-IR
PROX
Differential ADC Output of IR and Proximity IR and proximity sensing with Range 2; 15Ω @ IRDR
Sensing With Object Far Away to Provide pin, IS<1:0> = 0, Freq = 0; E = 210 lux, Sunlight.
No Reflection
1.0
%
NOTES:
2. V
is the common voltage to V
and V
DDD DDA.
SUP
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.
2
do ADC conversion with proximity sensing if it receives an I C
command of continuous measurement. It will continuously
Principles of Operation
Photodiodes and ADC
update the data registers with the latest conversion data. It will
go to the power-down mode after it receives the I C command
of power-down.
2
The ISL29021 contains a photodiode array which converts
infrared energy into current. The spectral response for IR
sensing is shown in Figure 6 in the performance curves section.
After IR radiation is converted to current during the infrared
signal processing, the current output is converted to digital by a
Infrared and Proximity Sensing
There are four operational modes in ISL29021: programmable
IR sensing once with auto power-down, programmable
proximity sensing once with auto power-down, programmable
continuous IR sensing and programmable continuous
proximity sensing. These four modes can be programmed in
series to fulfill the application needs. The detailed program
configuration is listed in “Register Set” on page 6.
2
built-in 16-bit Analog-to-Digital Converter (ADC). An I C
command reads the infrared light intensity in counts.
The converter is a charge-balancing integration 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. See “Integration and
Conversion Time” on page 7.
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.
The built-in ADC offers user flexibility in integration time or
conversion time. Integration time is determined by an internal
oscillator (f
), and the n-bit (n = 4, 8, 12,16) counter inside
OSC
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.
the ADC. A good balancing act of integration time and
resolution depending on the application is required for optimal
results.
2
The ADC has I C programmable range select to dynamically
accommodate various IR conditions. For very dim
conditions, the ADC can be configured at its lowest range
(Range 1). For very bright conditions, the ADC can be
configured at its highest range (Range 4) in the proximity
sensing.
Low-Power Operation
The ISL29021 initial operation is at the power-down mode
after a supply voltage is provided. The data registers contain
Interrupt Function
2
the default value of 0. When the ISL29021 receives an I C
The active low interrupt pin is an open drain pull-down
2
command to do a one-time measurement from an I C master,
2
configuration. There is also an interrupt bit in the I C register.
it will start ADC conversion with 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 ISL29021 will continuously
The interrupt serves as an alarm or monitoring function to
determine whether the infrared light level or the proximity
detection level exceeds the upper threshold or goes below the
lower threshold. The user can also configure the persistency
FN6732.0
March 3, 2009
4
ISL29021
of the interrupt. An unexpected camera flash, for example,
can be ignored by setting the persistency to 8 integration
cycles.
Figure 1 shows a sample one-byte read. Figure 2 shows a
sample one-byte write. The I C bus master always drives
2
the SCL (clock) line, while either the master or the slave can
drive the SDA (data) line. Figure 2 shows a sample write.
2
I C Interface
2
Every I C transaction begins with the master asserting a
There are eight 8-bit registers available inside the ISL29021.
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 and the Timer output. The data registers contain
the ADC's latest digital output, or the number of clock cycles in
the previous integration period. The four 8-bit interrupt registers
hold 16-bit interrupt high and low thresholds.
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 I C transaction ends with
the master asserting a stop condition (SDA rising while SCL
remains high).
2
2
For more information about the I C standard, please consult
2
™ 2
The ISL29021’s I C interface slave address is internally hard-
the Philips I C specification documents.
wired 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.
START
DEVICE ADDRESS
A
A
A
9
REGISTER ADDRESS
DEVICE ADDRESS
A
A
DATA BYTE0
W
STOP START
2
I C DATA
2
I C SDA
A6 A5 A4 A3 A2 A1 A0 W
SDA DRIVEN BY MASTER
R7 R6 R5 R4 R3 R2 R1 R0
SDA DRIVEN BY MASTER
A
A
9
A6 A5 A4 A3 A2 A1 A0
W
SDA DRIVEN BY ISL29021
IN
2
I C SDA
SDA DRIVEN BY MASTER
A D7 D6 D5 D4 D3 D2 D1 D0
OUT
2
I C CLK
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
9
2
FIGURE 1. I C READ TIMING DIAGRAM SAMPLE
START
DEVICE ADDRESS
W
W
A
A
A
REGISTER ADDRESS
A
FUNCTIONS
A
STOP
2
I C DATA
2
I C SDA IN
A6 A5 A4 A3 A2 A1 A0
SDA DRIVEN BY MASTER
R7 R6 R5 R4 R3 R2 R1 R0
SDA DRIVEN BY MASTER
A
B7 B6 B5 B4 B3 B2 B1 B0
SDA DRIVEN BY MASTER
A
2
I C SDA OUT
A
9
A
2
I C CLK IN
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
9
2
FIGURE 2. I C WRITE TIMING DIAGRAM SAMPLE
FN6732.0
March 3, 2009
5
ISL29021
Register Set
There are eight registers that are available in the ISL29021. Table 1 summarizes their functions.
TABLE 1. REGISTER SET
BIT
ADDR
00h
01h
02h
03h
04h
05h
06h
07h
REG NAME
COMMANDI
COMMANDII
7
6
5
4
3
2
1
PRST1
RANGE1
D1
0
PRST0
RANGE0
D0
DEFAULT
00h
OP2
1
OP1
FREQ
D6
OP0
IS1
0
0
FLAG
RES0
D2
IS0
RES1
D3
00h
DATA
D7
D5
D4
00h
LSB
DATA
D15
TL7
TL15
TH7
TH15
D14
TL6
D13
TL5
TL13
TH5
TH13
D12
TL4
TL12
TH4
TH12
D11
TL3
TL11
TH3
TH11
D10
D9
D8
00h
MSB
INT_LT_LSB
INT_LT_MSB
INT_HT_LSB
INT_HT_MSB
TL2
TL1
TL0
00h
TL14
TH6
TH14
TL10
TH2
TH10
TL9
TL8
00h
TH1
TH0
FFh
TH9
TH8
FFh
.
Command Register I 00(hex)
TABLE 4. INTERRUPT PERSIST
The first command register has the following functions:
BITS 1 TO 0
NUMBER OF INTEGRATION CYCLES
00
01
10
11
1
4
1. Operation Mode: Bits 7, 6, and 5.These three bits
determines the operation mode of the device.
8
TABLE 2. OPERATION MODE
16
BITS 7 TO 5
000
OPERATION
Power-down the device
Command Register II 01(hex)
001
Reserved (Do not use)
IR once
The second command register has the following functions:
010
1. Proximity Sensing Scheme: Bit 7. This bit programs the
function of the proximity detection. Logic 1 of this bit,
Scheme 1, makes n-1 (3, 7, 11, 15) bits (2’s
011
Proximity once
100
Reserved (Do not use)
Reserved (Do not use)
IR continuous
complementary) proximity_less_ambient detection. The
101
(n-1)
range of Scheme 1 proximity count is from -2
2
to
(n-1)
110
, Scheme 1 proximity detection is less affected by
the ambient IR noise variation.
111
Proximity continuous
TABLE 5. PROXIMITY SENSING SCHEME
2. Interrupt flag; Bit 2. 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.
Once triggered, INT pin stays low and the status bit stays
high. Both interrupt pin and the status bit are automatically
cleared at the end of Command Register I transfer.
BIT 7
OPERATION
0
1
Reserved
Sensing IR from LED with ambient IR rejection
2. Modulation Frequency: Bits 6. This bit sets the IR LED
driver’s modulation frequency.
TABLE 3. INTERRUPT FLAG
TABLE 6. MODULATION FREQUENCY
BIT 2
OPERATION
Interrupt is cleared or not triggered yet
Interrupt is triggered
MODULATION FREQUENCY
0
1
BITS 6
(kHz)
DC
0
1
360
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.
3. Amplitude of IR driver current: Bits 5 and 4. This device
provides current source to drive an external IR LED. The
drive capability can be programmed through Bits 5 and 4.
For example, the device sources 12.5mA out of the IRDR
pin if Bits 5 and 4 are 0.
FN6732.0
March 3, 2009
6
ISL29021
.
Registers 06 and 07 hex set the high (HI) threshold for the
TABLE 7. CURRENT SOURCE CAPABILITY AT IRDR PIN
interrupt pin and the interrupt flag. 06 hex is the LSB and 07
hex is the MSB. By default, the Interrupt threshold HI is FF
hex for both LSB and MSB.
BITS 5 TO 4
IRDR PIN SOURCE CURRENT
12.5mA IR LED driver
00
01
10
11
25mA IR LED driver
50mA IR LED driver
100mA IR LED driver
Integration and Conversion Time
The ADC resolution and f
determines the integration
OSC
time, t
.
int
n
R
4. 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 (A/D) converter
samples the photodiode current signal for a measurement.
n
1
EXT
(EQ. 1)
-------------
---------------------------------------------
t
= 2
×
= 2
×
int
f
725kHz × 499kΩ
OSC
where n is the number of bits of resolution and n = 4, 8, 12 or
16. 2 , therefore, is the number of clock cycles. n can be
programmed at the command register 01(hex) bits 3 and 2.
n
.
TABLE 11. INTEGRATION TIME OF n-BIT ADC
TABLE 8. RESOLUTION/WIDTH
R
(kΩ)
EXT
BITS 3 TO 2 NUMBER OF CLOCK CYCLES
n-BIT ADC
n = 16-BIT
45ms
n = 12-BIT
2.812ms
n = 8-BIT
175.5µs
351µs
n = 4-BIT
10.8µs
16
00
01
10
11
2
2
2
= 65,536
= 4,096
16
12
8
250
12
8
499**
90ms
5.63ms
21.6µs
= 256
**Recommended R
resistor value
EXT
4
2 = 16
4
External Scaling Resistor R
Range
for f and
OSC
EXT
5. Range: Bits 1 and 0. The Full Scale Range (FSR) can be
2
adjusted via I C using Bits 1 and 0. Table 9 lists the
The ISL29021 uses an external resistor R
to fix its
EXT
possible values of FSR for the 499kΩ R
resistor.
EXT
internal oscillator frequency, f
. Range. f
and Range
OSC
are inversely proportional to R
OSC
. For user simplicity, the
TABLE 9. RANGE/FSR
EXT
BITS 1:0
k
1
2
3
4
RANGE(k)
Range1
Range2
Range3
Range4
FSR @ IR SENSING
Refer to page 3
Refer to page 3
Refer to page 3
Refer to page 3
proportionality constant is referenced to 499kΩ:
(EQ. 2)
(EQ. 3)
499kΩ
00
01
10
11
-----------------
Range =
× Range(k)
R
EXT
499kΩ
-----------------
f
=
× 725kHz
OSC
R
EXT
Noise Rejection
Data Registers (02 hex and 03 hex)
In general, integrating type ADC’s have excellent
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.
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...k ) is zero. Similarly, setting the
i
device’s integration time to be an integer multiple of the
periodic noise signal, greatly improves the proximity sensor
output signal in the presence of noise.
TABLE 10. DATA REGISTERS
ADC Output in IR Sensing
ADDRESS
(hex)
CONTENTS
The ISL29021’s ADC output codes, DATA, are directly
proportional to the IR intensity received in the IR sensing.
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
DATA = β × E
(EQ. 4)
IR
IR
03
D15 is MSB for 16-bit resolution, D11 is MSB for
12-bit resolution
Here, E is the received IR intensity. The constant β
IR
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.
Interrupt Registers (04, 05, 06 and 07 hex)
Registers 04 and 05 hex set the low (LO) threshold for the
interrupt pin and the interrupt flag. 04 hex is the LSB and 05
hex is the MSB. By default, the Interrupt threshold LO is 00
hex for both LSB and MSB.
ADC Output in Proximity Sensing
In the proximity sensing, the ADC output codes, DATA, are
directly proportional to the total IR intensity from the
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ISL29021
background IR noise and from the IR LED driven by the
ISL29021 as shown in Equation 5.
LED Modulation for Proximity Detection
ISL29021 offers two ways to modulate the LED in the
Proximity Detection mode - DC or 360kHz (with 50% duty
cycle) by bit 6 of register 01h. At the IRDR pin, there are four
different IRDR LED currents; 12.5, 25, 50, and 100mA
outputs selectable by bits 4 and 5 of register 01h. With the
LED running in the DC mode, the proximity detection is twice
as sensitive but consumes 2x more current. The sensitivity
of LED 50mA, DC 50mA is identical to that of 100mA,
360kHz modulation. Please note that the ISL29021 does not
include a LED.
DATA
= β × E + γ × E
IR LED
(EQ. 5)
PROX
Here, β and E have the same meanings as in Equation 4.
IR
The constant γ depends on the spectrum of the used IR LED
and the ADC’s range and resolution selections. E
is the
LED
IR intensity which is emitted from the IR LED and reflected
by a specific objector to the ISL29021. E depends on the
LED
current to the IR LED and the surface of the object. E
LED
decreases with the square of the distance between the
object and the sensor.
Current Consumption Estimation
If background IR noise is small, E can be neglected, and
IR
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 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 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
360kHz modulated frequency, during the entire operation
cycle that includes 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 6:
the ADC output directly decreases with the distance. If there
is significant background IR noise, ISL29021 is to do a
proximity sensing using Scheme 1 to do on-chip background
IR noise subtraction.
Figure 9 shows ISL29021 configured at 12-bit ADC
resolution and sensitivity range select at 16000 (range 3) for
the proximity reading. A 12.5mA external LED current at
360kHz modulation frequency detects three different sensing
objects: 92% brightness paper, 18% gray card and ESD
black foam. Figure 10 shows ISL29021 configured at 12-bit
ADC resolution and sensitivity range select at 1000
(range 1) for the proximity reading, with a programmed
external LED at 360kHz modulation frequency, detecting 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.
∗
∗
[(0.05mA + 0.05mA + 1mA + (50mA 50%)) 0.4ms)]/30ms = 0.35mA
(EQ. 6)
ISL29021 Proximity sensing relies on the amount of IR
reflected back from the objects to be detected. Clearly, it can
not detect an optically black object that reflects no light.
However, ISL29021 is sensitive enough to detect a black ESD
foam, which reflects slightly less than 1% of IR, as shown in
Figure 9. For biological objects, blonde hair reflects more than
brunette hair, as expected and shown in Figure 11. Also 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. This
characteristic is very different from that of a plain paper
reflector.
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 7:
∗
∗
[(0.05mA + 0.05mA + 1mA + (50mA 50%)) 7ms)]/100ms = 1.83mA
(EQ. 7)
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.
Interrupt Function
http://www.intersil.com/data/tb/TB477.pdf
Depending on the mode of operation set by Bits 7, 6 and 5 of
command register 00 hex, the upper and lower interrupt
thresholds are for either infrared signal level or proximity
detection. After each change of mode of operation, it is
expected a new set of thresholds are loaded to interrupt
registers 04, 05, 06 and 07 hex for proper interrupt detection.
Also, the interrupt persist counter will be reset to 0 when the
mode of operation is changed.
Layout Considerations
The ISL29021 is relatively insensitive to layout. Like other
2
I C devices, it is intended to provide excellent performance
even in significantly noisy environments. There are only a
few considerations that will ensure best performance.
2
Route the supply and I C 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.
FN6732.0
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ISL29021
Soldering Considerations
Typical Circuit
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.
A typical application for the ISL29021 is shown in Figure 4.
2
The ISL29021’s I C address is internally hardwired as
2
1000100. The device can be tied onto a system’s I C bus
2
together with other I C compliant devices.
30ms
1µ
IR
50µ
0.4ms
PROXIMITY
0.4ms
1mA
IR LED
50mA
360 kHz
FIGURE 3. CURRENT CONSUMPTION FOR EACH INTEGRATION PHASE AND DETECTION CYCLE
1.7V TO 3.63V
2
I C MASTER
R2
10kΩ
R3
10kΩ
R1
10kΩ
MICROCONTROLLER
INT
SDA
2.25V TO 3.63V
SCL
SLAVE_0
2
SLAVE_1
I C SLAVE_n
8
7
1
2
SDA
SDA
VDDD IRDR
SCL
SCL
VDDA
INT
6
5
3
4
GND
SDA
SCL
REXT
REXT
499k
ISL29021
C2
0.1µ
C1
1µ
FIGURE 4. ISL29021 TYPICAL CIRCUIT
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ISL29021
Typical Performance Curves V
(V
, V
) = 3V, R
= 499kΩ
SUP DDD DDA
EXT
1.2
1.2
SUN
INCANDESCENT
1.0
0.8
0.6
0.4
0.2
0
1.0
0.8
0.6
0.4
0.2
0
IR AND
PROXIMITY
SENSING
HALOGEN
FLUORESCENT
-0.2
300
400
500
600
700
800
900 1000 1100
300
400
500
600
700
800
900 1000 1100
WAVELENGTH (nm)
WAVELENGTH (nm)
FIGURE 6. SPECTRAL RESPONSE FOR PROXIMITY
SENSING
FIGURE 5. SPECTRUM OF FOUR LIGHT SOURCES
10000
RADIATION PATTERN
0¬
92% BRIGHTNESS PAPER
1000
10¬
10¬
20¬
20¬
LUMINOSITY
ANGLE
30¬
30¬
40¬
40¬
18% GRAY CARD
100
50¬
60¬
50¬
60¬
70¬
80¬
70¬
80¬
90¬
10
ESD BLACK FOAM
90¬
1.0
1
0.2 0.4
RELATIVE SENSITIVITY
0.6 0.8
0
20
40
60
80
100
DISTANCE (mm)
FIGURE 8. ADC OUTPUT vs DISTANCE WITH DIFFERENT
OBJECTS IN PROXIMITY SENSING
FIGURE 7. RADIATION PATTERN
350
4500
12-BIT ADC
RANGE 3
fLED = 328kHz
4000
3500
3000
2500
2000
1500
1000
500
300
250
200
150
100
50
I
I
= 100mA
= 50mA
= 25mA
IRLED
IRLED
PIG'S SKIN
ILED = 12.5mA
4mm CENTER-TO-CENTER
FOR ISL29021 AND SFH4650,
ISOLATED BY BARRIER
AND BEHIND A 65%
I
IRLED
IRLED
I
= 12.5mA
IR TRANSMITTING GLASS
18% GRAY
130 CTS = 500 CTS x 65% x 65%
= 211 CTS
BLOND HAIR
BRUNETTE HAIR
0
0
0
10
20
30
40
50
60
70
80
90
0
10
20
30
40
50
60
DISTANCE (mm)
DISTANCE (mm)
FIGURE 10. PROXIMITY DETECTIONS OF VARIOUS
BIOLOGICAL OBJECTS
FIGURE 9. ADC OUTPUT vs DISTANCE WITH DIFFERENT
LED CURRENT AMPLITUDES IN PROXIMITY
SENSING
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ISL29021
Typical Performance Curves V
(V
, V
) = 3V, R
= 499kΩ (Continued)
SUP DDD DDA
EXT
105.0
104.5
104.0
103.5
103.0
102.5
102.0
101.5
101.0
100.5
100.0
PROXIMITY SENSING
IS<1:0> = 0
-40
-20
0
20
40
60
80
100
120
TEMPERATURE (¬×C
FIGURE 11. OUTPUT CURRENT vs TEMPERATURE IN PROXIMITY SENSING
2.10
1
8
2
3
7
6
2.00
0.40
0.54
4
5
0.37
FIGURE 12. 8 LD ODFN SENSOR LOCATION OUTLINE
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 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
FN6732.0
March 3, 2009
11
ISL29021
Package Outline Drawing
L8.2.1x2.0
8 LEAD OPTICAL DUAL FLAT NO-LEAD PLASTIC PACKAGE (ODFN)
Rev 0, 10/08
6
A
2.10
PIN #1
INDEX AREA
B
6
PIN 1
INDEX AREA
0.50
2.00
1.50
1.50
0.20±0.0
M
0.10 C A B
(2X)
0.10
8X 0 . 35 ± 0 . 0
0.75
TOP VIEW
BOTTOM VIEW
SEE DETAIL "X"
C
0.10
0.70±0.0
C
BASE PLANE
SEATING PLANE
0.08 C
SIDE VIEW
(6x0.50)
(1.50)
(8x0.20)
5
C
0 . 2 REF
(8x0.55)
(0.75)
0 . 00 MIN.
0 . 05 MAX.
TYPICAL RECOMMENDED LAND PATTERN
DETAIL "X"
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 ± 0.0
4. Dimension b applies to the metallized terminal and is measured
between 0.25mm and 0.35mm from the terminal tip.
Tiebar shown (if present) is a non-functional feature.
5.
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.
FN6732.0
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12
相关型号：
ISL29028A_1103
Low Power Ambient Light and Proximity Sensor with Intelligent Interrupt and Sleep Modes
INTERSIL
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