LX1973B EVAL KIT datasheet, PDF

LX1973B

TM

®

Automotive Light Sensor

P

RODUCTION

D

ATA

S

HEET

DESCRIPTION

KEY FEATURES

Nearly Perfect

Best Eye™

Human Eye Spectral Response

Dark Current < 0.0005 Lux (@

25°C)

5 Decades Compressed Output

10% Accuracy Over

Temperature

Scalable Output Voltage

No Optical Filters Needed

The LX1973B is a wide dynamic

range light sensor with a very low

dark current that is optimized for

sensing low level light signals that

typically occur under dark or darkening

outdoor ambient lighting.

The LX1973B has been optimized

for automotive systems such as

headlamp brightness control or rear

view mirror contrast control. Its

radical (fractional exponent) response

when interfaced with an 8 bit DAC

can detect levels down to 0.001 Lux

or levels as high as 500 Lux.

The spectral response of the

integrated light sensor closely

emulates the human eye so it ignores

light such as infrared which emits

energy but doesn’t aid vision. This

eliminates the need for an Infrared

filter required with competitor’s light

sensors.

The LX1973B internal circuitry

consists of a diode array with

Microsemi’s

Best Eye™

processing that

provides a nearly perfect photopic light

wavelength response curve. The sensor

output feeds into a wide dynamic range

compression amplifier that provides

accurate resolution over five decades of

ambient light. The integrated dark

current cancellation circuit facilitates

accurate sensing of light below 0.01

Lux. The current source output of the

LX1973B can be gain scaled using one

external resistor.

The LX1973B is internally trimmed

to an initial accuracy of 5% at room

temperature and a light level of 10 Lux.

Accuracy of 10% is maintained over the

full temperature range (-40 to +85ºC).

WWW .

Microsemi

.C

OM

APPLICATIONS

Auto Headlamp Control

Auto Mirror Contrast Control

IMPORTANT:

For the most current data, consult

MICROSEMI’s

website:

http://www.microsemi.com

Protected By US Patents: 6,787,757; Patents Pending

PRODUCT HIGHLIGHT

LX 1973B Response

5V

4

3

LX1973B

Part

VOUT

R

LOAD

Output (volts)

2

1

0

0.001

0.01

0 .1

1

10

100

LX1973B

A m b ien t L ig h t (lu x )

PACKAGE ORDER INFO

T

A

(°C)

-40 to 85

PL

Plastic MSOP Domed

8-Pin

LX1973BIPL

PR

Plastic MSOP Domed

8-Pin Reverse Form

LX1973BIPR

RoHS Compliant / Pb-free, NiPdAu Finish

Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX1973BIPL-

xxxxx-TR)

Copyright

©

2007

Rev. 1.3, 2008-01-11

Microsemi

Analog Mixed Signal Group

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 1

LX1973B

TM

®

Automotive Light Sensor

P

RODUCTION

D

ATA

S

HEET

PACKAGE PIN OUT

ABSOLUTE MAXIMUM RATINGS

V

DD

................................................................................................................. -0.3 to 6 V

DC

SNK/SRC (Output Compliance Voltage)........................................... -0.3 to V

DD

+ 0.3V

DC

SNK/SRC (Maximum Output Current)................................................... Internally Limited

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

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

RoHS / Pb-free Peak Package Solder Reflow Temperature

(40 seconds maximum exposure)..................................................................240°C (+0, -5)

Notes:

1. Exceeding these ratings could cause damage to the device. All voltages are with

respect to Ground. Currents are positive into, negative out of specified terminal.

V

DD

NC

OUT

PL P

ACKAGES

(Top View)

V

SS

NC

WWW .

Microsemi

.C

OM

973B

YWWB

PL P

ACKAGE

M

ARKING

(Bottom View)

V

SS

NC

V

DD

NC

OUT

THERMAL DATA

973B

YWWB

PL

PR

Plastic MSOP Domed 8-Pin

Plastic MSOP Domed 8-Pin Reverse Form

39°C/W

206°C/W

V

SS

NC

V

DD

NC

OUT

THERMAL RESISTANCE

-

JUNCTION TO

C

ASE

,

θ

JC

THERMAL RESISTANCE

-

JUNCTION TO

A

MBIENT

,

θ

JA

PR P

ACKAGE

M

ARKING

(Top View)

Junction Temperature Calculation: T

J

= T

A

+ (P

D

x

θ

JA

).

The

θ

JA

numbers are guidelines for the thermal performance of the device / pc-board

system. All of the above assume no ambient airflow.

V

DD

NC

OUT

PR P

ACKAGES

(Bottom View)

V

SS

NC

FUNCTIONAL PIN DESCRIPTION

Name

V

DD

V

SS

OUT

1 Power Supply Voltage

8 Ground Reference for Power and Signal Output

4 Output Current

Description

NC – No Connection

MSL3/240°C/168 Hours

SIMPLIFIED BLOCK DIAGRAM

PACKAGE

V

DD

LX1973B

Photopic

Sensor with

Dark Current

Cancellation

Pre Amplifier

Compression

Amplifier

OUT

GND

LX1973B

Figure 1 –

Simplified Block Diagram

LX1973BIPL

Copyright

©

2007

Rev. 1.3, 2008-01-11

LX1973BIPR

Microsemi

Analog Mixed Signal Group

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 2

LX1973B

TM

®

Automotive Light Sensor

P

RODUCTION

D

ATA

S

HEET

The following specifications apply over the operating ambient temperature -40°C

≤

T

A

following test conditions: See Note 1, V

DD

=5V, R

OUT

= 10k.

ELECTRICAL CHARACTERISTICS

≤

85°C except where otherwise noted and the

WWW .

Microsemi

.C

OM

Parameter

Operational Voltage

Supply Current

Power Supply Rejection Ratio

Peak Spectral Response

Infrared Response

Light to Current Gain

Saturation Current

Dynamic Response Time

(to 10% Settling Error Point)

Dome Top Package

Output Current

Dark Current (Equivalent Lux)

Dome Bottom Package

Output Current

Dark Current (Equivalent Lux)

Symbol

V

DD

I

DD

PSRR

λ

PR

Test Conditions

@ 1 Lux

V

RIPPLE

= 100mV

P-P

, f = 10kHz; C

OUT

= 0.1µF

E

V(white)

= 100 Lux, E

V(810nm)

= 14.6µWatt/ cm²,

Note 3

See application section for equation

LX1973B

Units

Min Typ Max

4.5

30

0.22

35

580

1

5.5

0.27

V

mA

dB

nm

%

I

DD

(

λ

)

I

DD

(

λ

PR

)

G

L

I

SAT

T

DR

I

OUT(0.01)

I

OUT(1.0)

I

OUT(10)

I

OUT(100)

I

OUT (DARK)

I

OUT(0.01)

I

OUT(1.0)

I

OUT(10)

I

OUT(100)

I

OUT (DARK)

-5

5

520

1.0 Lux to 0.01 Lux

0.01 Lux to 1.0 Lux

E

V

= 0.01 Lux @ 25°C, Note 1,2

E

V

= 1.0 Lux, Note 1,2

E

V

= 10 Lux, Note 1,2

E

V

= 100 Lux, Note 1,2

E

V

= 0 Lux, T

A

= 20°C, Note 4

E

V

= 0 Lux, T

A

= 50°C, Note 4

E

V

= 0.01 Lux @ 25°C, Note 1,2

E

V

= 1.0 Lux, Note 1,2

E

V

= 10 Lux, Note 1,2

E

V

= 100 Lux, Note 1,2

E

V

= 0 Lux, T

A

= 20°C, Note 4

E

V

= 0 Lux, T

A

= 50°C, Note 4

36

114

202

369

0.63

0.2

40

126

224

410

190

700

40

124

223

405

190

700

1.25

0.5

44

139

246

451

380

1400

44

137

245

445

380

1400

µA

sec

µA

µLux

µA

µLux

36

112

201

365

E

LECTRICALS

E

LECTRICALS

Notes:

1. The input irradiance is supplied from a point source which is a white light emitting diode (LED); Fairchild Semiconductor part number

MV8W00.

2. See Figure 2.

3. See Figure 3.

4. Dark Current equivalent Lux at 0 Lux:

EL

= ⎢

I

OUT

⎥ ÷

(146

×

10

−

9

)

⎣

I

REF

⎦

⎡

⎤

4

For Dome Top Package, I

REF

= 6446µA.

For Dome Bottom Package, I

REF

= 6344µA.

LX1973B

Copyright

©

2007

Rev. 1.3, 2008-01-11

Microsemi

Analog Mixed Signal Group

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 3

LX1973B

TM

®

Automotive Light Sensor

P

RODUCTION

D

ATA

S

HEET

TEST CIRCUITS

V

DD

V

DD

WWW .

Microsemi

.C

OM

V

DD

White

LED

V

DD

V

OUT

R

LOAD

White

LED

810nm

OUT

Part

GND

OUT

Part

GND

V

OUT

R

LOAD

LX1973B

Figure 2 –

Operational Voltage Measurement Circuit

LX1973B

Figure 3 –

IR Sensitivity Measurement Circuit

APPLICATION CIRCUITS

5V

LX1973B

Part

10K

1µF

LX1800

SCL

SCD

ADR

GND

VDD

REF

AIN

5V

Part

2.5V

AOUT

DAC / ADC

HI

BRT

Headlamp

Controller

Lamp

Figure 4 –

Typical Application

LX1973B

Copyright

©

2007

Rev. 1.3, 2008-01-11

Microsemi

Analog Mixed Signal Group

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 4

LX1973B

TM

®

Automotive Light Sensor

P

RODUCTION

D

ATA

S

HEET

APPLICATIONS

G

ENERAL

D

ESCRIPTION

WWW .

Microsemi

.C

OM

The LX1973B produces an output current that is sensitive to the level of ambient light that falls onto the photosensitive

area of the IC package. The sensitivity is amplified and compressed to provide ratio metric accuracy across several

decades. The sensitivity function is:

I

OUT

(

P

)

=

I

ref

0.25

×

[

E

DARK

+

E

AMBIENT

]

0.25

1 Lux

0.25

= 1

0.25

I

ref

= 126µA for the Domed Top Package

I

ref

= 124µA for the Domed Bottom Package

E

DARK

= dark current equivalent Lux expressed in Lux from a white LED point source.

E

AMBIENT

= ambient illumination expressed in Lux from a white LED point source.

LX1973B

Copyright

©

2007

Rev. 1.3, 2008-01-11

Microsemi

Analog Mixed Signal Group

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 5

Parameter Name	Attribute value
sensor type	Light, current output
Sensing range	-
interface	simulation
Sensitivity	550nm
Voltage - Power	4.5 V ~ 5.5 V
Embedded	no
What's included	plate
IC/parts used	LX1973B

LX1973B EVAL KIT

LX1973B EVAL KIT Overview

LX1973B EVAL KIT Parametric

Preview

LX1973B EVAL KIT Related Products

Recommended Resources