LX1973 ® TM Automotive Light Sensor P RODUCTION D ATA S HEET KEY FEATURES DESCRIPTION The LX1973 internal circuitry consists of a diode array 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 LX1973 can be gain scaled using one external resistor. The LX1973 is internally trimmed to an initial accuracy of 5% at room temperature and a light level of 10lux. Accuracy of 10% is maintained over the full temperature range (-40 to +85C). Human Eye Spectral Response 25C Dark Current < 0.005 lux 5 Decades Compressed Output 10% Accuracy Over Temperature Scalable Output Voltage No Optical Filters Needed APPLICATIONS Auto Headlamp Control Auto Mirror Contrast Control WWW . Microsemi .C OM The LX1973 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 LX1973 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. IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com Protected by US Patent: 6,787,757; Patents Pending PRODUCT HIGHLIGHT LX1973 Response 5V LX1973 Part VOUT 10k Output (in Volts) NC 4.0000 3.0000 2.0000 1.0000 0.0000 0.001 0.01 0.1 1 10 100 Ambient Light (in lux) LX1973 PACKAGE ORDER INFO TA (°C) DU Plastic MSOP 8-pin RoHS Compliant / Pb-free -40 to 85 LX1973IDU Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX1973IDU-TR) Copyright © 2004 Rev. 1.0 2006-01-04 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 1 LX1973 ® TM Automotive Light Sensor P RODUCTION D ATA S HEET ABSOLUTE MAXIMUM RATINGS PACKAGE PIN OUT VDD 1 8 VSS NC 2 7 NC NC 3 6 NC OUT 4 5 NC DU PACKAGE (Top View) Notes: 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. 1 8 6 THERMAL DATA 1973 7 xxxx Solder reflow to follow: IPC/JEDEC J-STD-020B 7/02 Pb-SN Small Body Profile 5 2 WWW . Microsemi .C OM VDD ................................................................................................................. -0.3 to 6 VDC SNK/SRC (Output Compliance Voltage)........................................... -0.3 to VDD + 0.3VDC SNK/SRC (Maximum Output Current)................................................... Internally Limited Maximum Operating Junction Temperature ..............................................................150°C Operating Temperature Range ........................................................................ -40 to +85°C Storage Temperature Range.............................................................................-55 to 125°C Peak Package Solder Reflow Temp. (40 seconds maximum exposure) .......... 260° (+0, -5) 3 4 PACKAGE MARKING (Bottom View) DU Plastic MSOP 8-Pin xxxx – Denotes Date Code / Lot information THERMAL RESISTANCE-JUNCTION TO CASE, θJC 39°C/W 206°C/W THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA RoHS / Pb-free 100% matte Tin Lead Finish Junction Temperature Calculation: TJ = TA + (PD x θJA). The θJA numbers are guidelines for the thermal performance of the device/pc-board system. All of the above assume no ambient airflow. FUNCTIONAL PIN DESCRIPTION Name Description VDD Input Supply Voltage VSS Ground Reference for Power and Signal Output OUT Output Current VDD Input Supply Voltage SIMPLIFIED BLOCK DIAGRAM PACKAGE PHOTO VDD Compression Amplifier Pre Amplifier OUT PACKAGE DATA Photopic Sensor with Dark Current Cancellation GND In Package Trim NC Figure 1 – Simplified Block Diagram Copyright © 2004 Rev. 1.0 2006-01-04 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 2 LX1973 ® TM Automotive Light Sensor P RODUCTION D ATA S HEET ELECTRICAL CHARACTERISTICS Parameter Operational Voltage Supply Current Power Supply Rejection Ratio Peak Spectral Response 85°C except where LX1973 Typ Symbol Test Conditions VDD IDD PSRR λPR EV = 1 lux VRIPPLE = 100mVP-P, f = 10kHz; COUT = 0.1µF 30 0.2 35 550 EV(550nm) = EV(800nm) = 146nW/cm, Note 3 -5 1 5 % 34 108 342 650 38 120 380 42 132 418 µA µA µA µA 450 2100 900 10000 µLux 1.5 3 sec Infrared Response IDD (λ ) IDD (λ PR ) Light to Current Gain Output Current Output Current Output Current Saturation Current GL IOUT(0.01) IOUT(1.0) IOUT(100) ISAT Dark Current (Equivalent lux) ≤ IOUT (DARK) Dynamic Response Time TDR Min 4.5 See application section for equation EV = 0.01 lux @ 25°C EV = 1 lux, Note 2 EV = 100 lux, Note 2 EV = 0 lux, TA = 20°C, Note 4 EV = 0 lux, TA = 50°C, Note 4 10% settling error (146 nW/cm² to 1.46 nW/cm² step response) Radiant Sensitive Area Units Max 5.5 0.25 V mA dB nm WWW . Microsemi .C OM Unless otherwise specified, the following specifications apply over the operating ambient temperature -40°C ≤ TA otherwise noted and the following test conditions: See Note 1, VDD =5V, ROUT = 10k. 2 0.20 mm Notes: 1. The input irradiance (EV) is supplied from a white light-emitting diode (LED) optical source adjusted to impose the specified EV at λ = 550nm. 2. See Figure 1. 3. See Figure 2. 4 4. Dark Current equivalent lux at 0 lux: ⎤ ⎡ I EL = ⎢ OUT ⎥ ÷ 146 ×10 −9 6163µA ⎦ ⎣ TEST CIRCUITS VDD VDD LX1973 LX1973 VDD PartOUT NC GND VOUT 10kΩ White LED PartOUT VOUT NC 800nm GND ELECTRICALS White LED VDD 10kΩ Figure 3 – IR Sensitivity Measurement Circuit Figure 2 – Operational Voltage Measurement Circuit Copyright © 2004 Rev. 1.0 2006-01-04 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 3 LX1973 ® TM Automotive Light Sensor P RODUCTION D ATA S HEET APPLICATION CIRCUITS WWW . Microsemi .C OM 5V 5V Part LX1973 10K 1µF LX1800 VDD SCL To µP SCD GND ADR Part 2.5V REF AIN AOUT DAC/ADC BRT HEADLAMP CONTROLLER LAMP Figure 4 – Typical Application APPLICATION CIRCUITS GENERAL DESCRIPTION The LX1973 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 = [ 6163µA × PDARK + PAMBIENT 0.25 W 2 cm ( ) ]0.25 APPLICATIONS where PDARK is the dark current equivalent power and PAMBIENT is the ambient illumination both expressed in W/cm² at a 555nm wavelength. PDARK is approximately 7pW/cm² at 25°C. Copyright © 2004 Rev. 1.0 2006-01-04 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 4 LX1973 ® TM Automotive Light Sensor P RODUCTION D ATA S HEET SENSITIVITY DARK CURRENT VS TEMP Dark Equiv Lux (uLux) Output Current (uA) 500 400 300 200 100 10000 1000 Limit 100 Typical 10 1 0 0 0.001 0.01 0.1 1 10 WWW . Microsemi .C OM 600 100 1000 10 20 30 40 50 60 70 80 85 Temperature (°C) Ambient Light (lux) IOUT STEP RESPONSE 2 Amplitude (µW/cm ) RESPONSE VS WAVELENGTH LX1973 Range 16 14 12 10 8 6 4 2 0 0 0.5 1 Time (Seconds) Load = 3.8kΩ and 1µF Photo Step = Direct Light Input of 14.6µW/cm2 VDD = 5.5V VDD = 5V 6 5 4 3 2 CHARTS Maximum Output Votage (V) MAXIMUM OUTPUT VOLTAGE 1 0 1 10 100 1000 Output Current (uA) Copyright © 2004 Rev. 1.0 2006-01-04 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 5 LX1973 ® TM Automotive Light Sensor P RODUCTION D ATA S HEET PACKAGE DIMENSIONS 8-Pin Miniature Shrink Outline Package (MSOP) D Top View E1 S e E A A1 b c Θ L1 L Dim A A1 b c D e E E1 L L1 S Θ MILLIMETERS MIN MAX – 1.10 0.05 0.15 0.26 0.41 0.13 0.23 2.90 3.10 0.65 BSC 4.75 5.05 2.90 3.10 0.41 0.71 0.95 BSC 0.525 BSC 3° INCHES MIN MAX – 0.043 0.002 0.006 0.010 0.016 0.005 0.009 0.114 0.122 0.025 BSC 0.187 0.198 0.114 0.122 0.016 0.028 0.037 BSC 0.021 BSC 3° WWW . Microsemi .C OM DU Side Views Active Area Required Minimum Light footprint Bonding / Wafer area Active Area C B CL Examination of Active Area Recommended light footprint pattern Copyright © 2004 Rev. 1.0 2006-01-04 INCHES 1.22 0.85 0.60 0.60 0.048 0.033 0.024 0.024 P1 2.5 0.98 Note: P1 represents a possible light footprint and its dimensions are not subject to strict tolerances. Only the active area of the device is required to be covered with light. This larger footprint is designed to ensure coverage of the device’s active area. Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 MECHANICALS P1 (recommended) MILLIMETERS Dim A a B C Page 6 LX1973 TM ® Automotive Light Sensor P RODUCTION D ATA S HEET NOTES WWW . Microsemi .C OM NOTES PRODUCTION DATA – Information contained in this document is proprietary to Microsemi and is current as of publication date. This document may not be modified in any way without the express written consent of Microsemi. Product processing does not necessarily include testing of all parameters. Microsemi reserves the right to change the configuration and performance of the product and to discontinue product at any time. Copyright © 2004 Rev. 1.0 2006-01-04 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 7