ISL29038_技术文档

DATASHEET

ISL29038

FN7851

Rev 1.00

January 23, 2015

Low Power Ambient Light and Proximity Sensor with Enhanced Infrared Rejection

The ISL29038 is a low power Ambient Light Sensor (ALS) and

Features

proximity (PROX) sensor. It has a built-in IR-LED driver for

proximity function. The ALS function measures the amount of

light (in the visible spectrum) incident on the ISL29038.

• Ideal for applications under dark or tinted glass

• Enhanced ambient sunlight rejection to 40k Lux

The ALS function has a programmable ambient IR-rejection,

which allows fine tuning of light source variations and is ideal

for light sensor applications under dark protective glass. The

ALS provides a 12-bit measurement. A passive optical filter

removes unwanted wavelengths (IR or Ultraviolet) to ensure

accurate ALS measurement.

• Programmable proximity sleep time between proximity

measurements optimizes power consumption

• Hardware interrupt - no polling required

• Programmable IR compensation to fine tune ALS

performance for various glass compositions

• Up to 4000 Lux, four selectable ALS ranges

• Programmable IR LED drive current to 250mA

The proximity function includes a new offset adjustment to

compensate for the IR light reflected off the inside of the

protective glass cover and back to the ISL29038 sensor. This

offset adjustment allows the sensor to compensate for these

internal reflections and preserve the dynamic range of the

proximity measurement.

• Operates from 2.25V to 3.63V V

DD

• Power-down I

DD,

typical 0.2µA

DC

• Tiny 2.1x2.0x0.7 (mm) ODFN package

The built-in current-driver pulses an external infrared LED at a

programmed current for 90µs. The infrared light that is

reflected and received by ISL29038 is digitized by an 8-bit

ADC. The proximity sensor also has a passive optical filter

designed to pass IR and reject visible wavelengths.

Applications

• Display dimming and adjustment

- Mobile devices: smart phones, PDA, GPS

- Computing: monitors, laptops, notebooks

- Picture frames, tablet_PCs, LCD_TV

The ISL29038 provides a hardware pin to indicate an interrupt

event. The interrupt pin saves power as the host microcontroller

can ‘wake-up’ on an interrupt event and does not need to poll

the device for an interrupt event. The interrupt generator is

user configurable and provides several options for ALS and

PROX trigger configurations. The ISL29038 supports an

• Object detection

- Touchscreen disabling

- Smart power-saving

2

SMBus compatible I C interface for configuration and control.

100

90

VDD_PULLUP

80

VDD_IRLED

250mA

SCL, SDA AND

INT PULL UPs

D

IRLED

IRDR

INT

SDA

1

70

R

100

C

1µF

2

1

U1

SMBus MASTER

125mA

1

2

3

4

8

7

6

5

60

GNDIR

AVDD

AGND

REXT

INT

SDA

SCL

VDD_ANALOG

50

C

2

62.5mA

SCL

40

1µF

ISL29038

R

499k

1

30

31.25mA

R : 499k 1% RESISTOR

20

10

0

1

R : 100Ω 5% RESISTOR

2

C , C : 1µF CERAMIC 10V CAPACITOR

1

2

D : OSRAM SFH4650 INFRARED LED

1

0

20

40

60

80

18% GREY CARD PROXIMITY DISTANCE (mm)

FIGURE 1. TYPICAL APPLICATIONS CIRCUIT

FIGURE 2. PROXIMITY SENSITIVITY

FN7851 Rev 1.00

January 23, 2015

Page 1 of 15

ISL29038

VDD

2

ALS PHOTODIODE

ARRAY

COMMAND

REGISTER

PHOTODIODE

AMPLIFIERS

(ALS AND IR)

DUAL CHANNEL

ADCs

DATA

REGISTER

GNDIR

SCL

1

5

6

2

I C

IR PHOTODIODE

ARRAY

SDA

IREF

INTERRUPT

IR DRIVER

INT

7

8

FOSC

IRDR

3

4

REXT

GND

FIGURE 3. ISL29038 BLOCK DIAGRAM

Pin Configuration

Pin Description

ISL29038

PIN#

NAME

GNDIR

VDD

DESCRIPTION

Ground for IRDR LED Current.

Positive supply: 2.25V to 3.63V.

Ground.

(8 LD ODFN)

TOP VIEW

1

2

3

4

GNDIR

VDD

1

2

3

4

8

7

6

5

IRDR

INT

GND

REXT

External Resistor, Connect to GND pin through a

499kΩ 1% resistor.

THERMAL

PAD

2

5

6

7

8

-

SCL

SDA

INT

I C Serial Clock Input.

GND

SDA

SCL

2

I C Serial Data Input/Output.

REXT

Active Low, Open-Drain Output.

IRDR

TPAD

IR-LED Driver Sink - Connect to IR LED Cathode.

Thermal Pad - Connect to GND.

Ordering Information

PART NUMBER

PART

V

RANGE

(V)

TEMP RANGE

(°C)

PKG.

DWG. #

DD

(Notes 1, 2, 3)

MARKING

PACKAGE

8 Lead ODFN

ISL29038IROZ-T7

N/A

Evaluation Board

2.25 to 3.63

-40 to +85

L8.2.1x2.0

ISL29038IROZ-EVALZ

NOTES:

1. 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), see device information page for ISL29038. For more information on MSL see techbrief TB477.

FN7851 Rev 1.00

January 23, 2015

Page 2 of 15

ISL29038

Thermal Information

Absolute Maximum Ratings

V

Supply Voltage between VDD and GND . . . . . . . . . . . . . . . . . . . . . .4.0V

Thermal Resistance (Typical)

8 Ld ODFN (Notes 4, 5) . . . . . . . . . . . . . . . .

Maximum Die Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+90°C

Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +100°C

Operating Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +85°C

Pb-Free Reflow Profile (*) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see TB477

*Peak temperature during solder reflow +260°C max



(°C/W)

88



JC

(°C/W)

14

DD

JA

2

I C Bus Pin Voltage (SCL, SDA). . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to 4.0V

2

I C Bus Pin Current (SCL, SDA). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <10mA

REXT Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-0.5V to VDD + 0.5V

IRDR Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5.5V

INT Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to 4.0V

INT Pin Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <10mA

ESD Rating

Human Body Model (Note 6). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 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.

NOTES:

4.  is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See Tech

JA

Brief TB379.

5. For  , the “case temp” location is the center of the exposed metal pad on the package underside.

JC

6. Tested per JESD22-A114E, ESD on all pins is 2kV except IRDR, which is 1.5kV.

Electrical Specifications

V

= 3.0V, T = +25°C, R

EXT

= 499kΩ 1% tolerance.

DD

A

MIN

MAX

PARAMETER

DESCRIPTION

TEST CONDITION

(Note 7) TYP (Note 7) UNITS

INPUT POWER

V

Power Supply Range

2.25

3.0

0.2

125

95

3.63

1.0

V

DD

I

Supply Current when Powered Down

Supply Current for ALS+Prox in Sleep Time

Supply Current for Prox in Sleep Time

Supply Current for ALS

ALS_EN = 0; PROX_EN = 0

ALS_EN = 1; PROX_EN = 1

ALS_EN = 0; PROX_EN = 1

ALS_EN = 1; PROX_EN = 0

µA

DD_OFF

I

140

DD_NORM

I

DD_PRX_SLP

I

95

DD_ALS

ADC (ALS AND PROX)

t

12-bit ALS Conversion Time

8-bit Prox Conversion Time

ALS Result when Dark

80

95

0.50

1

110

0.6

ms

INTGR_ALS

t

0.4

INTGR_PROX

DATA

E

= 0 Lux, 2k range

Counts

ALS_0

ALS_F

AMBIENT

Full-Scale ALS ADC Code

> selected range maximum Lux

4095 Counts

%

ΔDATA

Output Variation Over Light Sources:

Fluorescent, Incandescent and Sunlight

Ambient light sensing, no cover glass

After programmable active IR compensation

(Note 8)

±10

1

DATA

ΔDATA

Output Variation Over Light Sources:

Fluorescent, Incandescent and Sunlight

Ambient light sensing under cover glass

After programmable active IR compensation

(Note 8)

%

2

DATA

Linearity

ALS ADC Data Linearity

20% - 80% of full range

±5

%

DATA

Light Count, ALS_Range 125 Lux

E = 50 Lux (Note 9),

ALS_RANGE = 0

1555

771

1767

1979 Counts

ALS_0

ALS_1

ALS_2

ALS_3

Light Count, ALS_Range 250 Lux

Light Count, ALS_Range 2000 Lux

Light Count, ALS_Range 4000 Lux

E = 50 Lux (Note 9),

ALS_RANGE = 1

876

665

331

1

981

745

371

Counts

E = 300 Lux (Note 9),

ALS_RANGE = 2

585

292

E = 300 Lux (Note 9),

ALS_RANGE = 3

DATA

Prox Data without Object in Path

Full-Scale Prox ADC Code

Counts

PROX_0

255

PROX_F

FN7851 Rev 1.00

January 23, 2015

Page 3 of 15

ISL29038

Electrical Specifications

V

= 3.0V, T = +25°C, R

EXT

= 499kΩ 1% tolerance. (Continued)

DD

A

MIN

MAX

PARAMETER

ProxWASH

DESCRIPTION

TEST CONDITION

(Note 7) TYP (Note 7) UNITS

Washout Bit Activation Level

Norwood Solar Emulator

40k

27

Lux

ProxOffsetMax Maximum PROX Offset, Referenced to

Proximity ADC Range

512

LSB

ProxOffsetInc Proximity Offset Adjust Increment Referenced

to Proximity ADC Range

LSB

LED DRIVER (IRDR PIN)

t

Rise Time for IRDR Sink Current

Fall time for IRDR Sink Current

IRDR Sink Current

R

= 15Ω at IRDR pin, 20% to 80%

= 15Ω at IRDR pin, 80% to 20%

25

15

ns

r

f

LOAD

t

I

PROX_DR = 0; V

PROX_DR = 1; V

PROX_DR = 2; V

PROX_DR = 3; V

= 0.5V

= 3.63V

31.25

62.5

125

250

mA

µA

V

IRDR_0

IRDR_1

IRDR_2

IRDR_3

IRDR

IRDR Sink Current

I

IRDR Leakage Current

IRDR Pin Voltage Compliance

PROX_EN = 0; V

0.001

1

IRDR_LEAK

V

Register bit PROX_DR = 0

0.50

4.3

IRDR

t

I

On Time Per PROX Reading

IRDR

90

µs

PULSE

MISCELLANEOUS

V

Voltage of REXT Pin

ALS_EN = 1 or PROX_EN = 1

0.52

V

REF

2

I C Electrical Specifications For SCL and SDA unless otherwise noted, V = 3V, T = +25°C, R

= 499kΩ 1% tolerance

EXT

DD

A

(Note 11).

MIN

(Note 7)

MAX

(Note 7)

SYMBOL

PARAMETER

Supply Voltage Range for I²C Interface

SCL Clock Frequency

TEST CONDITIONS

TYP

UNITS

2

V

1.7

3.63

V

kHz

V

I C

f

400

SCL

V

SCL and SDA Input Low Voltage

SCL and SDA Input High Voltage

Hysteresis of Schmitt Trigger Input

0.55

IL

V

1.25

V

IH

V

0.05V

V

hys

DD

V

Low-level Output Voltage (open-drain) at 4mA Sink

Current

0.4

V

OL

I

Input Leakage for each SDA, SCL Pin

-10

10

50

µA

ns

i

t

Pulse Width of Spikes that must be Suppressed by

the Input Filter

SP

SCL Falling Edge to SDA Output Data Valid

Capacitance for each SDA and SCL Pin

Hold Time START Condition

900

10

ns

pF

ns

AA

C

i

t

After this period, the first clock

pulse is generated

600

HD:STA

t

LOW Period of the SCL Clock

Measured at the 30% of VDD

crossing

1300

ns

LOW

t

HIGH Period of the SCL Clock

Set-up Time for a START Condition

Data Hold Time

600

30

ns

HIGH

t

SU:STA

t

HD:DAT

t

Data Set-up Time

100

SU:DAT

FN7851 Rev 1.00

January 23, 2015

Page 4 of 15

ISL29038

2

I C Electrical Specifications For SCL and SDA unless otherwise noted, V = 3V, T = +25°C, R

= 499kΩ 1% tolerance

EXT

DD

A

(Note 11). (Continued)

MIN

MAX

(Note 7)

SYMBOL

PARAMETER

TEST CONDITIONS

TYP

UNITS

ns

(Note 7)

20 + 0.1xC

600

t

Rise Time of both SDA and SCL Signals

Fall Time of both SDA and SCL Signals

Set-up Time for STOP Condition

Bus Free Time Between a STOP and START Condition

Capacitive Load for Each Bus Line

SDA and SCL System Bus Pull-Up Resistor

Data Valid Time

(Note 12)

R

b

t

ns

F

t

ns

SU:STO

t

1300

ns

BUF

C

400

pF

kΩ

µs

V

b

R

Maximum determined by t and t

F

1

pull-up

VD;DAT

VD:ACK

R

t

0.9

t

Data Valid Acknowledge Time

V

Noise Margin at the LOW Level

0.1VDD

0.2VDD

nL

V

Noise Margin at the HIGH Level

V

nH

NOTES:

7. Parameters with MIN and/or MAX limits are 100% tested at +25°C, unless otherwise specified. Temperature limits established by characterization

and are not production tested.

8. Cover glass assumes fixed infrared/visible light transmissivity ratio of 10.

9. The LED light source irradiance is calibrated to produce the same ALS count as a fluorescent light source of the same Lux level.

10. An 850nm infrared LED is used in production test for proximity/IR sensitivity testing.

2

11. All parameters in I C Electrical Specifications table are guaranteed by design and simulation.

12. C is the capacitance of the bus in pF.

b

2

FIGURE 4. I C TIMING DIAGRAM

FN7851 Rev 1.00

January 23, 2015

Page 5 of 15

ISL29038

2

Each I C transaction ends with the master asserting a stop

ISL29038 Configuration and

Control

condition (SDA rising while SCL remains high). For more

information about the I C standard, consult the Philips I C

specification documents.

2

™ 2

2

I C Interface

2

Timing specifications are included in “I C Electrical

Specifications” on page 4. The timing parameters are defined in

Figure 4.

ISL29038 configuration and control is performed using the I2C

or SMBus. The ISL29038’s I2C interface slave address is

internally hard wired as 8’b1000100x, where x denotes the R/W

bit.

2

The I C interface on the ISL29038 supports single and multiple

byte read and write transfers using the random-read/write

protocol. The ISL29038 does not support I C ‘Repeat Start’

protocol.

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 time after every transmitted byte.

2

NOTE: That in most system implementations, the ISL29038 is connected

2

to a single I C master with one or more slave devices, consequently,

2

absence of ‘Repeat Start’ function does not adversely affect I C bus

Figure 5 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.

system performance.

START

DEVICE ADDRESS

A

9

REGISTER ADDRESS

DEVICE ADDRESS

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

9

A6 A5 A4 A3 A2 A1 A0

W

SDA DRIVEN BY ISL29038

MASTER

2

I C SDA

SDA DRIVEN BY MASTER

A D7 D6 D5 D4 D3 D2 D1 D0

SLAVE (ISL29038)

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 5. I C DRIVER TIMING DIAGRAM FOR MASTER AND SLAVE CONNECTED TO COMMON BUS

FN7851 Rev 1.00

January 23, 2015

Page 6 of 15

ISL29038

Typical Performance Curves

100

ALS RESPONSE (BLUE)

RANGE: 2k Lux

90

80

90

80

250mA

70

60

50

70

CIE 1924 PHOTOPIC CURVE

125mA

60

50

62.5mA

40

30

40

30

31.25mA

20

10

0

10

0

300

400

500

600

700

800

900

1000

1100

0

20

40

60

80

WAVELENGTH (nm)

18% GREY CARD PROXIMITY DISTANCE (mm)

FIGURE 6. PROXIMITY SENSITIVITY (Note 13)

FIGURE 7. ALS SENSITIVITY (Note 14)

100

15

90

80

70

60

50

40

30

20

10

0

10

5

50%

10%

0

-90

-60

-30

0

30

60

90

0

8k

16k

24k

32k

40k

AMBIENT LIGHT LEVEL (LUX)

ANGLE (°)

FIGURE 8. PROXIMITY AMBIENT LIGHT REJECTION (Note 15)

NOTES:

13. The ISL29038 Proximity distance sweeps with different IRDR LED current settings using an 18% Grey card reflector.

FIGURE 9. ALS ANGULAR SENSITIVITY (Note 16)

14. The ISL29038 Ambient Light Sensor Spectral response when compared to a theoretical CIE 1924 Photopic curve. The ‘Blue’ line shows the ISL29038

response and the ‘Red’ line depicts the CIE 1924 Photopic curve.

15. The ISL29038 Proximity Ambient Light Rejection using a Norwood Solar Emulator. At 40k lux ambient light level, the Proximity Washout Count (Reg

0x0D[7:1]) is 127 indicating a saturation in Proximity Signal processing path. The Proximity Washout bit 0x0D[0] is active at approximately 90% of

the maximum level. At 10% initial PROX count (due to optical leakage from IR LED to the ISL29038), the PROX data error is under 2%. At 50% initial

PROX count (severe optical leakage), the PROX data error is about 7%.

16. The Ambient Light Sensor Angular Sensitivity of the ISL29038 using a white LED light source.

FN7851 Rev 1.00

January 23, 2015

Page 7 of 15

ISL29038

ISL29038 Register Set

TABLE 1. CONFIGURATION AND CONTROL REGISTERS

ADDRESS

(HEX)

POWER-ON REGISTER

DEFAULT ACCESS

BIT

FIELDS

FUNCTION

NAME/VALUE

REGISTER NAME

Device ID

FUNCTION

0x00

b11000xxx RO

[7:0]

Device Identification

ISL29038 Device ID

Reserved

[7:3]

[2:0]

[7:0]

[7:6]

[5]

[11000]

0x01

Config0

0x00

RW

Proximity Configuration

Reserved

PROX_EN

[1]

Proximity Enable/Disable

Enable

[0]

Disable

RW

[4:2]

PROX_SLP

[000]

[001]

[010]

[011]

[100]

[101]

[110]

[111]

IRDR_DRV

[00]

Proximity Sleep Time Select

400ms

100ms

50ms

25ms

12.5ms

6.25ms

3.125ms

0ms

RW

[1:0]

IR LED Current

31.25mA

[01]

62.5mA

[10]

125mA

[11]

250mA

0x02

Config1

0x00

RW

[7:0]

[7]

Proximity/ALS Configuration

Interrupt Algorithm

Window Comparator

Hysteresis Window

Proximity Offset Compensation

Ambient Light Sensing Enable/Disable

Enable

INT_ALG

[1]

[0]

RW

[6:3]

[2]

PROX_OFFSET

ALS_EN

[1]

[0]

Disable

RW

[1:0]

ALS_RANGE

[00]

Ambient Light Sensor Range Select

125 Lux

[01]

250 Lux

[10]

2000 Lux

[11]

4000 Lux

0x03

0x04

Config2

0x00

0x10

RW

[7:0]

[7:5]

[4:0]

ALS_IR_COMP

Ambient Light Sensor IR Compensation

Reserved

ALSIRComp

INTConfig

ALS Infra Red Compensation

(Unsigned Binary)

INTConfig

RW

[7:0]

Interrupt Configuration, Status and Control

FN7851 Rev 1.00

January 23, 2015

Page 8 of 15

ISL29038

TABLE 1. CONFIGURATION AND CONTROL REGISTERS (Continued)

ADDRESS

(HEX)

POWER-ON REGISTER

DEFAULT ACCESS

BIT

FIELDS

FUNCTION

NAME/VALUE

REGISTER NAME

FUNCTION

RO

[7]

PROX_INT_FLG

Proximity Interrupt Flag

Proximity Interrupt Event

[1]

[0]

No Proximity Interrupt Event

Proximity Interrupt Reporting Persistency

INT after 1 Proximity Flag Event

INT after 2 Consecutive Proximity Flag Event

INT after 4 Consecutive Proximity Flag Event

INT after 8 Consecutive Proximity Flag Event

Power Failure (Brown-out) Alarm

Brown-Out Detected

RW

[6:5]

PROX_PRST

[00]

[01]

[10]

[11]

RO

RW

[4]

PWR_FAIL

[1]

[0]

Normal Operation

[3]

ALS_INT_FLG

Ambient Light Sensor Interrupt Flag

ALS Interrupt Flag Event

[1]

[0]

No ALS Interrupt Flag Event

[2:1]

ALS_INT_PRST

[00]

ALS Interrupt Reporting Persistency

INT after 1 ALS Flag Event

[01]

INT after 2 Consecutive ALS Flag Event

INT after 4 Consecutive ALS Flag Event

INT after 8 Consecutive ALS Flag Event

Interrupt Output (Pin) Configuration

Interrupt if ALS and PROX Event

Interrupt if ALS or PROX Event

Proximity Interrupt LOW threshold

Proximity Interrupt HIGH threshold

ALS Interrupt LOW threshold bit[11:4]

ALS Interrupt LOW/HIGH threshold bits

ALS Interrupt LOW threshold bit[3:0]

ALS Interrupt HIGH threshold bit[11:8]

ALS Interrupt HIGH threshold bit[7:0]

Proximity Data (Unsigned Binary)

ALS Data HIGH Byte

[10]

[11]

RW

[0]

INT_CFG

[1]

[0]

0x05

0x06

0x07

0x08

PROX_INT_TL

PROX_INT_TH

ALS_INT_TL

0x00

RW

[7:0]

[7:4]

[3:0]

[7:0]

[7:4]

[3:0]

[7:0]

[7:1]

[0]

PROX_INT_TL

PROX_INT_TH

ALS_INT_TL1

0xFF

0x00

0x0F

ALS_INT_TLH

ALS_INT_TL0

ALS_INT_TH1

ALS_INT_TH0

PROX_DATA

0x09

0x0A

0x0B

ALS_INT_TH

PROX_DATA

ALS_DATA_HB

0xFF

RW

RO

ALS_DATA_HB

Set to 0000

ALS Data Bit[11:8]

0x0C

0x0D

ALS_DATA_LB

PROX_AMBIR

RO

ALS_DATA_LB

PROX_AMBIR

ALS Data Bit[7:0]

Proximity Mode Ambient IR Measurement

Proximity Mode Ambient IR Component

Proximity Washout Status

RO

PROX_WASH

[1]

Proximity Washout Detected

Normal Proximity Operation

[0]

0x0E

Config3

0x00

[7:0]

SoftReset

0x38

Software Reset

Initiate Soft Reset

0x00

Normal operation

FN7851 Rev 1.00

January 23, 2015

Page 9 of 15

ISL29038

Registers 0x01, 0x02 are used to configure the primary proximity

and ALS parameters. Register 0x03 is used for optimizing IR

compensation in ALS measurements. A procedure to optimize IR

compensation is described in “ALS IR Compensation” on page 11.

The ALS runs continuously with new data available every 90ms.

The proximity sensor runs continuously with a time between

conversions controlled by PROX_SLP (Reg 0x01[6:4]).

Ambient Light Sensing

Register 0x04 is the Interrupt Configuration and Status Register,

and is used primarily to indicate interrupt events from proximity

and ALS measurements. A PWR_FAIL bit to indicate a

‘Brown-Out’ event is available and is set in case of a power supply

interruption. A ‘Brown-Out’ event does not generate a hardware

interrupt. The host micro-controller must clear this bit by writing a

‘0’ to Reg 0x04[4].

The ISL29038 is set for ambient light sensing when Register bit

ALS_EN = 1. Four measurement ranges from 125 Lux to 4000 Lux

are available. The ALS measurement range is configured via Reg

0x02[1:0].

Proximity Sensing

When proximity sensing is enabled (PROX_EN = 1), the external

IR LED is driven for 100µs by the built-in IR LED driver through

the IRDR pin.

Register 0x04 is also used to configure ALS and Proximity

interrupt persistency and the operation of the INT pin.

Registers 0x05 and 0x06 are used to set the proximity ‘LOW’ and

‘HIGH’ threshold for proximity interrupt event generation.

ALS CONVERSION TIME = 90ms

_SEVERAL_{s BETWEEN}

(FIXED)

CONVERSIONS

Registers 0x07, 0x08 and 0x09 are used to set the ALS ‘LOW’

and ‘HIGH’ threshold. Two 12-bit numbers span three address

locations as shown in Table 1.

ALS

ACTIVE

90ms

TIME

Data registers 0x0A holds result of proximity conversion. The

proximity result should be validated by ‘Washout’ bit in Reg

0x0D[0]. Registers 0x0B and 0x0C hold results of an ALS

measurement.

0.50ms FOR PROX

CONVERSION

PROX

SENSOR

ACTIVE

The ALS data is 12 bits wide. Least Significant Byte of the ALS

data is available at address 0x0C and Most Significant Byte

(MSB) of ALS data is available at address 0x0B. The MSB is right

justified, i.e., the upper nibble is always zero and lower nibble

contains four data bits.

SERIES OF

IRDR

(CURRENT

DRIVER)

CURRENT PULSES

TOTALING 0.09ms

TIME

Register 0x0D[7:1] contains ambient IR measurement in

proximity measurement phase. This measurement is for

detecting ambient Washout condition, which is indicated by Reg

0x0D[0] being ‘HIGH’. Proximity ‘Washout’ is described in

“Proximity Ambient Washout Detection” on page 11.

SLEEP TIME

(PROX_SLP)

FIGURE 10. TIMING DIAGRAM FOR PROX/ALS EVENTS - NOT TO SCALE

The IR LED current depends on PROX_DRV (Reg 0x01[1:0]). Drive

current settings are as shown in Table 1. IR LED drive is in high

impedance state when not active.

A software reset can be initiated by writing 0x38 to Reg 0x0E.

ISL29038 Operation

Photodiodes and ADCs

The ISL29038 contains two photodiode arrays, which convert

photons (light) into current. The ALS photodiodes are designed to

mimic the human eye’s wavelength response curve to visible light.

The ALS photodiodes’ current output is digitized by a 12-bit ADC.

When the IR from the LED reaches an object and gets reflected

back to the ISL29038, the reflected IR light is converted into a

current. This current is converted to digital data using an 8-bit

ADC. The proximity measurement takes 0.5ms for one

conversion including the 90μs LED drive time. The period

between proximity measurements is determined by PROX_SLP

(sleep time) in Reg 0x01[4:2].

The ALS ADC output is accessed by reading from Reg 0x0B and

0x0C when the ADC conversion is completed.

Average LED driving current consumption is given by Equation 1.

I

 90s

lRDR;PEAK

The ALS ADC converter uses a charge-balancing architecture.

Charge-balancing is best suited for converting small current signals

in the presence of periodic AC noise. The ISL29038 targets an

integration time of 90ms, which can vary ±15% from nominal. The

ALS integration time is intended to minimize 60Hz flicker.

(EQ. 1)

----------------------------------------------------

I

=

lRDR;AVE

T

SLEEP

A typical IRDR scheme is 250mA pulses every 400ms, averaging

about 56μA DC.

The proximity sensor uses an 8-bit ADC, which operates in a

similar fashion. The IRDR pin drives (pulses) an infrared LED, the

emitted IR reflects off an object back into the ISL29038, and the

photo diodes convert the reflected IR to a current signal in

0.5ms. The ADC subtracts the IR reading before and after the

LED is driven to remove ambient IR contribution.

Total Current Consumption

Total current consumption is the sum of I and I . The IRDR

pin sinks current and the average IRDR current is calculated using

DD IRDR

Equation 1. The I depends on voltage and the mode of

DD

operation. For simplicity, Equation 1 ignores proximity ADC

conversion time since it is much smaller than the sleep time.

FN7851 Rev 1.00

January 23, 2015

Page 10 of 15

ISL29038

ALS IR Compensation

Proximity Ambient Washout Detection

The ISL29038 is designed for operation under dark glass cover.

Glass or plastic covers can significantly attenuate visible light

and pass the Infrared light without much attenuation.

Consequently, the ISL29038 under a glass cover experiences an

IR rich environment.

Optical proximity sensor can saturate when illuminated with

excessive ambient light. The ISL29038 provides a warning flag

when the proximity measurement may be erroneous due to

excessive ambient light. The PROX_WASH register (Reg 0x0D[0])

reports this condition.

The on-chip ALS passive optical filter on the ISL29038 is designed

to block most of the IR incident on the ALS photo diodes. In

addition, the ISL29038 provides a programmable active IR

compensation that subtracts residual IR still reaching the sensor.

Interrupts Events

The ISL29038 interrupts are designed to minimize host

microcontroller overhead of continuous polling. The ISL29038

can generate interrupts on the results of an ALS measurement or

proximity measurement.

The ALS_IR_COMP register (Reg 0x03[4:0]) allows fine tuning of

the residual infrared component from the ALS output.

The ALS interrupt event ALS_FLAG (Reg 0x04[3]) is governed by

Reg 0x07 through 0x09. Two-12 bit high and low threshold

values are written to these registers. The ISL29038 will set the

ALS interrupt flag if the ADC conversion count in Registers 0x0B

and 0x0C are outside the programmed thresholds. The

ALS_FLAG is cleared by writing a ‘0’ to Reg 0x04[3].

The recommended procedure for determining ALS IR

compensation is as follows:

• Illuminate the ISL29038 based product with a light source

without IR, such as a white LED. Record the ALS measurement

and the Lux level.

A proximity interrupt event (PROX_FLAG) is governed by the high

and low thresholds in Reg 0x05 and 0x06 (PROX_LT and

PROX_HT) and is indicated by Reg 0x04[7]. PROX_FLAG is set

when the measured proximity data is more than the higher

threshold. The proximity interrupt flag is cleared when the

proximity data is lower than the low proximity threshold or by

writing a ‘0’ to Reg 0x04[7].

• Illuminate the device with an IR LED and the White LED. Take

an ALS measurement and Lux level measurement.

• Adjust the ALS_IR_COMP register (Reg 0x03, bits 4:0) to

compensate for the IR contribution.

• Repeat steps above until the IR light source contribution to the

ALS measurement is under 10 percent assuming no change in

Lux level due to IR light source.

The Proximity interrupt generation can be selected between

‘out-of-window’ threshold and hysteresis schemes. When the

PROX_INT_ALG register (Reg 0x02, Bit 7) is set to 0, proximity

uses a window comparator scheme; when set to 1, proximity

uses a hysteresis scheme.

Proximity Offset

Systems built with a protective glass cover over the ISL29038

can provide light ‘leakage’ or ‘crosstalk’ from the IR LED by

reflection from the glass saturating the proximity sensor

measurement system (Figure 11).

In hysteresis mode, the interrupt event is generated if the

proximity ADC count is higher than the PROX_HT threshold and

the interrupt event is cleared when the proximity ADC count is

less than the PROX_LT threshold. The interrupt event flag can

also be cleared by writing a ‘0’ to Reg 0x04[7].

Saturation can occur when the reflection from the glass with no

object in the proximity detection space exceeds the full scale of

the measurement system. The ISL29038 proximity system

provides a user programmable proximity offset correction to

compensate for this reflection.

INTERRUPT PERSISTENCE

To minimize interrupt events due to ‘transient’ conditions, an

interrupt persistency option is available for both ALS and proximity

measurements. Persistency requires ‘X-consecutive’ interrupt flags

before the INT pin is driven low. Both ALS and PROX have their own

independent interrupt persistency options. ALS_PRST and

PROX_PRST configuration are controlled from Reg 0x04.

GLASS COVER

Power-Up and ‘Brown-Out’ Reset

SENSOR

LED

The ISL29038 has an enhanced power-on-reset system. A

‘Brown-Out’ detector flag in Reg 0x04[4] informs the system that

the device has powered-up properly. This flag should be reset as

part of the initialization sequence.

PCB

FIGURE 11. PROXIMITY SET-UP HIGHLIGHTING CROSSTALK

REFLECTED FROM COVER GLASS

A ‘Brown-Out’ condition is defined as an operating condition

when the power supply voltage is not within the specified limits.

The PROX_IR_COMP register (Reg 0x02[6:3]) applies a corrective

offset to the received signal prior to ADC conversion, which

allows the signal to be brought within the usable range of the

proximity measurement system.

2

During the brown-out period at power-up, the I C interface and

2

the IR LED driver are inactive. Following brown-out, the I C

interface is re-initialized and the configuration registers are set to

power-up default values. After power-up and during device

initialization, host should examine that the PWR_FAIL flag

FN7851 Rev 1.00

January 23, 2015

Page 11 of 15

ISL29038

(Reg 0x04[4]) is set and then clear the flag by writing ‘0’ to Reg

0x04[4].

Typical Application Circuit

A typical application circuit for the ISL29038 is shown in

Following power-up, a ‘Brown-Out’ condition, if detected, is

reported by PWR_FAIL flag by Reg 0x04[4]. Device configuration

registers are not set to their power-up default after ‘Brown-Out’.

PWR_FAIL flag should be periodically monitored to detect post

power-up power supply interruption.

2

Figure 12. The ISL29038’s I C address is internally hard wired as

‘1000100x’, with x representing the R/W bit. The device can be

2

connected to a system’s I C bus together with other I C

compliant devices. It is important to ensure that there is no

2

address conflict with other I C devices on the bus.

Power-Down

The SCL, SDA and INT pins on ISL29038 are open drain and

require pull-up resistors for proper system operation. Values of

the pull-up resistors is system dependent and can range from

2.2k to 10k depending upon the number of I C devices on the

bus.

Setting ALS_EN (Reg 0x02[2]) and PROX_EN (Reg 0x01[5]) to ‘0’

puts the ISL29038 into a power-down state with power supply

current dropping to less than 1µA. All configuration registers are

maintained in power-down mode.

2

The proximity sensing system can be powered using a dual power

supply or using a single power supply. In dual supply

Soft Reset

A software reset to ISL29038 can be initiated by writing 0x38 to

Reg 0x0E. Following reset, all configuration registers are set to

their default power-up state. After soft reset, the ISL29038

defaults to the power-down configuration.

configuration, the IR LED and the ISL29038 are powered from

separate power supplies. The V IRLED can range from 2.25V to

DD

5.0V and the V _ANALOG can range from 2.25V to 3.63V. In

DD

dual supply configuration, resistor R should not be installed.

2

In single supply configuration, the IR LED and the ISL29038 are

ALS Data Count Read Out

A 2 byte I C read from ALS_DATA_HB outputs MSB 1 data on

SDA. This data is LSB justified with a zero fill for unused bits.

powered from the same power source. The V _IRLED can range

DD

2

st

from 2.25V to 3.63V and the V _Analog is derived from

DD

V

_IRLED using resistor R .

DD

2

NOTE: That the MSB byte address precedes the LSB byte address. The

ALS count is 256*(ALS_DATA_HB) + ALS_DATA_LB.

In either power supply configuration, a 1µF decoupling capacitor

should be installed close to the AVDD pin, and another 1µF

decoupling capacitor should be placed close to the IR LED anode.

Proximity Detection of Various Objects

Proximity sensing relies on the amount of IR reflected back from

objects. A perfect black object would absorb all incident light and

reflect no photons. The ISL29038 is sensitive enough to detect

black ESD foam, which reflects only 1% of IR. Blonde hair typically

reflects more than brown hair and skin tissue is more reflective

than human hair.

IR penetrates into the skin and is reflected from within. As a

result, the proximity count generally peaks at contact and

monotonically decreases as skin moves away. The reflective

characteristics of skin are very different from that of a inanimate

object such as paper.

VDD_PULLUP

VDD_IRLED

SCL, SDA AND

INT PULL UPs

D

IRLED

IRDR

INT

SDA

SCL

1

R

100

C

1µF

2

1

U1

SMBus MASTER

1

2

3

4

8

7

6

5

GNDIR

AVDD

AGND

RExt

INT

SDA

SCL

VDD_ANALOG

C

2

1µF

ISL29038

R

1

499k

R : 499k 1% RESISTOR

1

R : 100Ω 5% RESISTOR

2

C , C : 1µF CERAMIC 10V CAPACITOR

1

2

D : OSRAM SFH4650 INFRARED LED

1

FIGURE 12. TYPICAL APPLICATIONS CIRCUIT

FN7851 Rev 1.00

January 23, 2015

Page 12 of 15

ISL29038

ISL29038 pins IRGND and AGND should connect to a low

impedance ground with low resistance and low inductance

traces. Ferrite beads and inductors should be avoided in the

ground path. If necessary, due to RF consideration, the effects of

DCR (DC resistance) should be evaluated on ALS and Proximity

system performance.

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. A

standard reflow soldering profile with a +260°C maximum is

recommended. Additional information regarding soldering

ISL29038 is included in Intersil Technical Brief TB477.

A 1µF ceramic decoupling capacitor should be placed as close to

the AVDD pin as possible.

Suggested PCB Footprint

Refer to TB477,“Surface Mount Assembly Guidelines for Optical

Dual FlatPack No Lead (ODFN) Package” before starting ODFN

product board mounting.

The ISL29038 drives the IR LED with 0.09ms current pulses. To

supply this pulsed current, a 1 to 10µF bulk decoupling capacitor

(C ) must be connected from the IR LED anode to the GNDIR pin

1

to minimize instantaneous resistive voltage drop. The connection

from IR LED cathode to the IRDR pin should be short and with

minimal inductance. Similarly, connection from the IR LED to

VDD must be made with a low impedance trace.

Additional information regarding soldering is also included in

Intersil Technical Brief TB477.

For most applications, a single power supply may be used to

PCB Layout Considerations

The ISL29038 is relatively insensitive to PCB layout. Adherence

to the following guidelines will ensure first pass success and best

performance.

power the IR LED and the ISL29038. Use of resistor R and

2

capacitor C (Figure 13) to help filter out the power supply noise

2

generated from IR LED switching is recommended for best

ISL29038 performance when using a single power supply. For

dual supply operation, resistor R should not be installed.

2

Route the I C/SMBus SCL, SDA and the INT traces away from

sources of switching noise. A 499k 1% tolerance resistor must be

connected from the REXT pin to AGND. This node also needs to

be isolated from any switching noise.

2.10

1

8

2

7

6

2.00

3

ALS SENSOR

OFFSET 0.03mm

ALS SENSOR AREA

0.66mm x 0.24mm

PROX SENSOR

OFFSET 0.42mm

4

5

PROX SENSOR AREA

0.57mm x 0.16mm

0.57

FIGURE 13. 8 LD ODFN SENSOR LOCATION OUTLINE - DIMENSIONS IN mm

FN7851 Rev 1.00

January 23, 2015

Page 13 of 15

ISL29038

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 revision.

DATE

REVISION

CHANGE

January 23, 2015

FN7851.1 Thermal Information table on page 3: changed theta JC value from 10 to 14.

Configuration and control registers on page 8; under Reg2 configure1 section: changed Window Comparator from

0 to 1 and Hysteresis Window from 1 to 0.

October 12, 2012

FN7851.0 Initial Release.

About Intersil

Intersil Corporation is a leading provider of innovative power management and precision analog solutions. The company's products

address some of the largest markets within the industrial and infrastructure, mobile computing and high-end consumer markets.

For the most updated datasheet, application notes, related documentation and related parts, please see the respective product

information page found at www.intersil.com.

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in the quality certifications found at www.intersil.com/en/support/qualandreliability.html

Intersil products are sold by description only. Intersil may modify the circuit design and/or specifications of products at any time without notice, provided that such

modification does not, in Intersil's sole judgment, affect the form, fit or function of the product. Accordingly, the reader is cautioned to verify that datasheets are

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otherwise under any patent or patent rights of Intersil or its subsidiaries.

For information regarding Intersil Corporation and its products, see www.intersil.com

FN7851 Rev 1.00

January 23, 2015

Page 14 of 15

ISL29038

Package Outline Drawing

L8.2.1x2.0

8 LEAD OPTICAL DUAL FLAT NO-LEAD PLASTIC PACKAGE (ODFN)

Rev 3, 1/11

A

2.10

6

0.15

B

PIN 1

INDEX AREA

0.25

6

0.50

PIN 1

INDEX AREA

1.50

2.00

0.20±0.05

4

0.10 M C A B

(2X)

0.10

8X 0 . 35 ± 0 . 05

TOP VIEW

0.75

BOTTOM VIEW

SEE DETAIL "X"

0.10 C

2.50

2.10

0.70±0.05

C

BASE PLANE

SEATING PLANE

0.08 C

SIDE VIEW

(6x0.50)

(1.50)

(8x0.20)

5

0 . 2 REF

C

(8x0.20)

0 . 00 MIN.

0 . 05 MAX.

(8x0.55)

DETAIL "X"

(0.75)

NOTES:

TYPICAL RECOMMENDED LAND PATTERN

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.

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.

FN7851 Rev 1.00

January 23, 2015

Page 15 of 15


型号：	ISL29038
厂家：	RENESAS TECHNOLOGY CORP
描述：	Low Power Ambient Light and Proximity Sensor with Enhanced Infrared Rejection
文件：	总15页 (文件大小：729K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

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