Rainbow Electronics MAX44000 User Manual

19-5859; Rev 0; 10/11

Ambient and Infrared Proximity Sensor

General Description

The MAX44000 combines a wide-dynamic range ambient
light sensor with an integrated infrared proximity sensor. The
IC is a perfect solution for touch-screen portable devices.

The IC can consume as low as 11µA (time averaged) in
ambient light sensing plus proximity sensing, including
external IR LED current.

The on-chip ambient sensor has the ability to make wide
dynamic range 0.03 lux to 65,535 lux measurements. An
on-chip IR proximity detector is matched with an inte­grated IR LED driver. All readings are available on an
I2C communication bus. A programmable interrupt pin
minimizes the need to poll the device for data, freeing
up microcontroller resources, reducing system software
overhead, and ultimately, reducing power consumption.

The IC is designed to drive an external IR LED and can
operate from a VDD of 1.7V to 3.6V. It consumes just 5µA
operating current when only the ambient light sensor is
enabled and 7µA when the proximity receiver and driver
are enabled.

Applications

Smartphones

Accessories

Industrial Sensors

Presence Detection

Simplified Block Diagram

Features

S Tiny, 2mm x 2mm x 0.6mm UTDFN-Opto Package

S VDD = 1.7V to 3.6V

S Low-Power Operation

5µA in Ambient Mode
7µA in Ambient Plus Proximity Mode
70µA in Ambient Plus Proximity Mode,

Including 100mA LED Current

S Excellent Light Source Matching

Programmable Green and IR Channel Gains

S Integrated Single-Pulse IR LED Driver

10mA to 110mA Programmable Range
Internal Ambient Cancellation

S -40NC to +105NC Temperature Range

Ordering Information

PART TEMP RANGE PIN-PACKAGE

MAX44000GDT+

+Denotes a lead(Pb)-free/RoHS-compliant package.

*EP = Exposed pad.

Typical Application Circuit appears at end of data sheet.

-40NC to +105NC

6 OTDFN-EP*

MAX44000

V

DD

MICROCONTROLLER

GND

IR LED

V

LED

V

DD

VIS + IR

(ALS)

IR (ALS)

IR (PRX)

DRV

GND

_______________________________________________________________ Maxim Integrated Products 1

ALS
PGA

ALS
PGA

AMBIENT

CANCELLATION

MAX44000

PRX
PGA

14-BIT

14-/8-BIT

I2C

SDA

SCL

INT

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.

Ambient and Infrared Proximity Sensor

ABSOLUTE MAXIMUM RATINGS

All Pins to GND ....................................................-0.3V to +4.0V

Output Short-Circuit Current Duration .......................Continuous

Continuous Input Current into Any Terminal ................... Q20mA

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.

Continuous Power Dissipation (TA = +70NC)

6-Pin OTDFN (derate 11.9mW/NC above +70NC) ............ 953mW

Operating Temperature Range ........................ -40NC to +105NC

Soldering Temperature (reflow) ......................................+260NC

MAX44000

ELECTRICAL CHARACTERISTICS

VDD = 1.8V, T

(

AMBIENT LIGHT RECEIVER CHARACTERISTICS

Maximum Ambient Light
Sensitivity

Ambient Light Saturation Level 65,535 Lux

Gain Error

Light Source Matching Fluorescent/incandescent light 10 %
Infrared Transmittance
Ultraviolet Transmittance

Dark Current Level

ADC Conversion Time

ADC Conversion Time Accuracy

INFRARED PROXIMITY RECEIVER CHARACTERISTICS

Maximum Proximity Detection
Sensitivity

Sunlight Rejection Offset No reflector 0 to 100k lux 0 Counts

Sunlight Rejection Gain Error With reflector 0 to 100k lux 0.1

– T

MIN

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

= -40°C to +105°C, TA = +25°C, unless otherwise noted.) (Note 2)

MAX

Fluorescent light (Note 3) 0.03 Lux/LSB

Green LED 538nm response, TA = +25NC
(Note 3)

850nm vs. 538nm, TA = +25NC
363nm vs. 538nm, TA = +25NC

100ms conversion time, 0 lux, TA = +25NC

14-bit resolution, has 50Hz/60Hz rejection 100
12-bit resolution 25
10-bit resolution 6.25
8-bit resolution 1.56
TA = -40NC to +105NC
TA = +25NC

850nm IR LED, 60µW/cm

2

15 %

0.5 %
2 %

0 Count

6

0.7

1.5

mW/cm2/

ms

%

LSB

Counts/

klux

2 ______________________________________________________________________________________

Ambient and Infrared Proximity Sensor

ELECTRICAL CHARACTERISTICS (continued)

VDD = 1.8V, T

(

IR LED TRANSMITTER

Minimum IR LED Drive Current
Sink

Maximum IR LED Drive Current
Sink

Current Control Step 10 mA

Current Control Accuracy

DRV Leakage Current I

Voltage Compliance of DRV Pin

Internal Transmit Pulse Width 100

POWER SUPPLY

Power-Supply Voltage V

Quiescent Current
(Ambient Mode)

Software Shutdown Current I

Quiescent Current Proximity During IR LED pulsed operation 375 600

Quiescent Current (ALS +
Proximity, Time Average)

Power-Up Time t

DIGITAL CHARACTERISTICS (SDA, SCL, INT)

Output Low Voltage (SDA, INT)
INT Leakage Current

SDA, SCL Input Current 0.01 1000 nA
I2C Input Low Voltage V
I2C Input High Voltage V
Input Capacitance 3 pF

– T

MIN

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

= -40°C to +105°C, TA = +25°C, unless otherwise noted.) (Note 2)

MAX

I

= 110mA, V

OUT

= 50mA, V

OUT

I

= 10mA, V

OUT

= 0mA, V

OUT

I

= 110mA, DI

DRV

I

= 100mA, DI

DRV

DD

Is 5 10

SHDN

ON

V

IL_I2C

IH_I2C

TA = +25NC
TA = -40NC to +105NC

With proximity and ALS sensing on 6.8

I

OL

= 6mA 0.06 0.4 V

SINK

SDA, SCL 0.4 V
SDA, SCL 1.6 V

= 1.5V 12

DRV

= 1.5V 10

DRV

= 1.5V 12

DRV

= 3.6V 0.1

DRV

= 10%; V

OUT

OUT

= 2%, V

DRV

DRV

= 3.6V

= 3.6V

10 mA

110 mA

0.5

0.6

1.7 3.6 V

0.1 0.3

0.6

100 ms

0.01 1000 nA

MAX44000

%I

FA

V

Fs

FA

FA

FA

FA

_______________________________________________________________________________________ 3

Ambient and Infrared Proximity Sensor

ELECTRICAL CHARACTERISTICS (continued)

VDD = 1.8V, T

(

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

I2C TIMING CHARACTERISTICS

Serial-Clock Frequency f

Bus Free Time Between STOP
and START

Hold Time (Repeated) START

MAX44000

Condition

Low Period of the SCL Clock t
High Period of the SCL Clock t

Setup Time for a REPEATED
START

Data Hold Time t
Data Setup Time t

SDA Transmitting Fall Time t

Setup Time for STOP Condition t
Pulse Width of Suppressed Spike t

Note 2: All devices are 100% production tested at TA = +25NC. Temperature limits are guaranteed by design.
Note 3: Guaranteed by design. Green 538nm LED chosen for production so that the IC responds to 100 lux flourescent light with

100 lux.

MIN

– T

= -40°C to +105°C, TA = +25°C, unless otherwise noted.) (Note 2)

MAX

SCL

t

BUF

t

HD,STA

LOW

HIGH

t

SU.STA

HD,DAT

SU,DAT

I

P 6mA, tR and tF between 0.3 x VDD

F

SU,STO

SP

SINK

and 0.7 x V

DD

400 kHz

1.3

0.6

1.3

0.6

0.6

0 0.9

100 ns

100 ns

0.6
0 50 ns

Fs

Fs

Fs
Fs

Fs

Fs

Fs

Typical Operating Characteristics

(VDD = 1.8V, T
Temperature limits are guaranteed by design.)

120

100

80

60

40

NORMALIZED OUTPUT

20

0

270 1070

4 ______________________________________________________________________________________

MIN

– T

= -40°C to +85°C, unless otherwise noted. All devices are 100% production tested at T

MAX

SPECTRUM RESPONSE

GREEN CHANNEL
RED CHANNEL
CIE CURVE

WAVE LENGTH (nm)

= +25°C.

A

ADC COUNT vs. DISTANCE

300

vs. LED DRIVE CURRENT

250

MAX44000 toc01

200

150

ADC COUNT

100

50

0

970870770670570470370

0 140

I

= 110mA

OUT

I

= 50mA

OUT

I

= 20mA

OUT

DISTANCE (mm)

MAX44000 toc02a

12010080604020

ADC COUNT vs. DISTANCE vs. OBJECT

300

250

200

150

ADC COUNT

100

50

0

GREY CARD

WHITE CARD

DISTANCE (mm)

9080706050403020100 100

MAX44000 toc02b

Ambient and Infrared Proximity Sensor

Typical Operating Characteristics (continued)

(VDD = 1.8V, T
Temperature limits are guaranteed by design.)

MIN

– T

= -40°C to +85°C, unless otherwise noted. All devices are 100% production tested at T

MAX

= +25°C.

A

MAX44000

LIGHT SENSITIVITY vs. LUX LEVEL

1800

ALSTIM[1:0] = 00

1600

ALSPGA[1:0] = 10

1400

1200

1000

800

ADC COUNT

600

400

200

0

0 1000

REFERENCE METER READING (LUX)

FLUORESCENT

INCANDESCENT

SUPPLY CURRENT vs. SUPPLY VOLTAGE

vs. TEMPERATURE

10

9

8

7

6

5

4

3

SUPPLY CURRENT (µA)

2

1

0

1.7 3.7

TA = +105°C

TA = -40°C

SUPPLY VOLTAGE (V)

MAX44000 toc03

ADC COUNT

900800600 700200 300 400 500100

TA = +85°C

TA = +25°C

STANDARD AMBIENT MODE

DARKROOM CONDITION

3.53.32.9 3.12.1 2.3 2.5 2.71.9

150

SUNLIGHT REJECTION

NO REFLECTOR

100

PRXTIM, PRXPGA : 0x02 = 1111 xxxx
LED CURRENT: 0x03 = xxxx 1110 for 100mA
WITH NO REFLECTOR, PROX COUNT STAYED
AT 0 AT ALL lux LEVEL
WITH A BLACK GLASS AS REFLECTOR AND
lux LEVEL CHANGED FROM 50 TO 75000 lux

50

PROX COUNTS DROPPED BY 7% AT MID-ADC RANGE
PROX COUNT DROPPED BY 35% AT QUARTER
ADC RANGE

0

0 80k

MAX44000 toc05

BLACK GLASS REFLECTOR

SUNLIGHT (LUX)

100

90

80

MAX44000 toc03b

70

60

50

40

30

20

RELATIVE SENSITIVITY (% FROM 0°)

10

70k60k50k40k30k20k10k

0

ROTATED WITH AXIS BETWEEN

PIN 1/2/3 AND 4/5/6

-50

-30

-70

-90 50 70 90

-40
LUMINOSITY ANGLE (°)

OUTPUT ERROR vs. TEMPERATURE

11

STANDARD AMBIENT MODE

10

DARKROOM CONDITION

9

V

= 1.7 V TO 3.6V

DD

8

7

6

5

4

COUNTS (UNITS)

3

2

1

0

-40 110
TEMPERATURE (°C)

RADIATION PATTERN

-20

-10

MAX44000 toc04

3010

40 60 80

20-60

0-80

MAX44000 toc06

85603510-15

_______________________________________________________________________________________ 5

Ambient and Infrared Proximity Sensor

51

Typical Operating Characteristics (continued)

(VDD = 1.8V, T
Temperature limits are guaranteed by design.)

MIN

– T

= -40°C to +85°C, unless otherwise noted. All devices are 100% production tested at T

MAX

= +25°C.

A

30

STANDARD AMBIENT MODE

MAX44000

25

20

15

10

SUPPLY CURRENT (µA)

5

0

1 100k

OUTPUT LOW VOLTAGE

vs. SINK CURRENT

180

THE DATA WAS TAKEN ON

160

THE INTERRUPT PIN

140

120

100

80

60

OUTPUT LOW VOLTAGE (V)

40

20

0

SINK CURRENT (mA)

SUPPLY CURRENT vs. LUX

10k100010010

LUX

MAX44000 toc09

2010

5

MAX44000 toc07

IR LED CURRENT vs. OUTPUT DRIVE

120

VOLTAGE, I

100

80

(mA)

60

DRV

I

40

20

0 1.0

vs. V

DRV

110mA I

50mA I

10mA I

V

(V)

DRV

DRV

DRV

DRV

DRV

SETTING

SETTING

SETTING

SUPPLY CURRENT vs. TIME

AMBIENT +
PROXIMITY MODE

100µs/div

70

60

MAX44000 toc10

50

40

30

TOTAL CURRENT (uA)

20

10

0.90.80.70.60.50.40.30.20.1

0

MAX44000 toc08

I

DRV

50mA/div

I

DD

200µA/div

TOTAL CURRENT CONSUMPTION

INCLUDING IR LED CURRENT

vs. IR LED CURRENT LEVEL

I

= IDD + I

TOTAL

AMBIENT + PROXIMITY MODE
100ms INTEGRATION TIME

IR_LED

I

IR LED LEVEL (mA)

TOTAL

I

DD

10080604020

MAX44000 toc11

120

6 ______________________________________________________________________________________

Ambient and Infrared Proximity Sensor

Pin Configuration

TOP VIEW

MAX44000

+

1

V

DD

2

GND SCL

3

DRV

*EP = EXPOSED PAD, CONNECT TO GND.

MAX44000

EP*

6

SDA

5

4

INT

Pin Description

PIN NAME FUNCTION

1 V
2 GND Ground
3 DRV IR LED Current Driver
4
5 SCL I2C Clock
6 SDA I2C Data

EP — Exposed Pad. EP is internally connected to GND. EP must be connected to GND.

DD

INT

Power Supply

Interrupt. Active-low output.

Detailed Description

The MAX44000 combines a wide-dynamic range ambi­ent light sensor with an integrated infrared proximity
sensor. The die is placed inside an optically transparent
(UTDFN-Opto) package. A photodiode array inside the
IC converts the light to a current, which is then pro­cessed by low-power circuitry into a digital value. The
data is then stored in an output register that is read by
an I2C interface.

The IC contains three types of photodiodes: a green pho­todiode and two types of infrared photodiodes. Ambient
light sensing (ALS) is accomplished by subtracting the
infrared ALS photodiode signal from the green ALS
photodiode signals after applying respective gains. The

_______________________________________________________________________________________ 7

infrared proximity photodiodes are optimized for better
sensitivity for near infrared signals, specifically 850nm,
and can be used for proximity sensor measurements.

In the ALS mode, the ALS photodiodes are connected to
two ADCs. The user can choose to view either just the
green ALS signal, or just the infrared ALS signal, or the
difference of the green and infrared ALS photodiodes.

In the proximity detect mode, the infrared proximity pho­todiodes are connected to the proximity receiver circuit
and then to an 8-bit ADC.

Three key features of the IC’s analog design are its low­power design, single-pulse proximity receive operation,
and interrupt pin operation.

Ambient and Infrared Proximity Sensor

The IC operates from a VDD of 1.7V to 3.6V and con­sumes just 5FA current in ALS mode and 7FA time-aver­aged in proximity mode. The on-chip IR proximity detec­tor DC ambient rejection circuitry is synchronized with
pulsing of an integrated IR LED transmitter to improve
noise immunity from external fluctuating IR sources.
This scheme also reduces IR LED power consumption
compared to alternate methods and eliminates red-glow
problems with the use of 850nm IR LEDs; power con-

MAX44000

sumption is reduced to 11FA (time averaged), includ­ing the current consumption of an external IR LED. An
on-chip programmable interrupt function eliminates the
need to continually poll the device for data, resulting in a
significant power saving.

Ambient Light Sensing

The ambient light sensors are designed to detect bright­ness in the same way as human eyes do. To achieve this,
the light sensor needs to have a spectral sensitivity that
is identical to the photopic curve of the human eye (see
Figure 1). Small deviations from the photopic curve can
affect perceived brightness by ambient light sensors to
be wildly different. However, there are practical difficul­ties in trying to reproduce the ideal photopic curve in a
small cost-efficient package. The IC instead uses two
different types of photodiodes (a green and an infrared)
that have different spectral sensitivities—each of which
is amplified and subtracted on-chip with suitable gain

coefficients so that the most extreme light sources (fluo­rescent and incandescent) are well matched to a com­mercial illuminance lux meter.

The photopic curve represents a typical human eye’s
sensitivity to wavelength. As can be seen in Figure 1
and Figure 2, its peak sensitivity is at 555nm (green).
The human eye is insensitive to infrared (> 700nm) and
ultraviolet (< 400nm) radiation.

Variation between light sources can extend beyond the
visible spectral range. For example, fluorescent and
incandescent light sources with similar visible brightness
(lux) can have substantially different IR radiation content
(since the human eye is blind to it). Since this infrared
radiation can be picked up by silicon photodiodes, dif­ferences in light spectra can affect brightness measure­ment of light sensors. For example, light sources with
high IR content, such as an incandescent bulb or sun­light, would suggest a much brighter environment than
our eyes would perceive them to be. Other light sources
such as fluorescent and LED-based systems have very
little infrared content. The IC incorporates on-chip com­pensation techniques to minimize these effects and still
output an accurate lux response in a variety of lighting
conditions.

On-chip user-programmable green channel and IR chan­nel gain trim registers allow the light sensor response to
be tailored to the application, such as when the light sen­sor is placed under dark or colored glass.

120

100

80

60

40

NORMALIZED RESPONSE

20

0

270 1070

WAVELENGTH (nm)

Figure 1. Spectral Response Compared to Ideal Photopic
Curve

8 ______________________________________________________________________________________

STANDARD ALS
(GREEN-RED)

970870770670570470370

Figure 2. Green Channel and IR Channel Response at
Identical Gains on a Typical MAX44000

120

100

80

60

40

NORMALIZED OUTPUT

20

0

270 1070

WAVELENGTH (nm)

GREEN CHANNEL
RED CHANNEL
CIE CURVE

970870770670570470370