LX1970 Visible Light Sensor I N T E G R A T E D P R O D U C T S PRODUCTION DATA SHEET DESCRIPTION KEY FEATURES The LX1970 is a new technology light Photo current is multiplied by (cid:131) Approximate Human Eye W W sensor with spectral response that integrated high gain amplifiers and is Spectral Response W emulates the human eye. made available at two output pins; one a (cid:131) Low IR Sensitivity . This device is ideal for monitoring current source and the other a current sink. (cid:131) Highly Accurate & M ambient light for brightness control These currents can easily be converted Repeatable Output Current ic vs. Light r systems in flat panel displays. It has a to voltage by adding a single resistor at o (cid:131) Voltage Scalable s unique photo diode arrangement (patents either or both outputs. Voltage gain is e (cid:131) Temperature Stable pending) with a peak response at 520 nm determined by the resistor value typically m (cid:131) Integrated High Gain Photo while sharply attenuating both ultra violet in the 10KΩ to 50KΩ range. Current Amplifiers i . C and infrared wavelengths. With accurate internal gain amplifiers, (cid:131) Complementary Current O The photo sensor is a PIN diode array design complexity and cost are greatly Outputs M with an accurate, linear, and very reduced. (cid:131) No Optical Filters Needed repeatable current transfer function. The LX1970 is available in the 8-pin MSOP. APPLICATIONS IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com (cid:131) PDA Protected By U.S. Patents: 6,787,757; Patents Pending (cid:131) Notebook PC (cid:131) LCD TV (cid:131) Tablet PC (cid:131) Cell phones PRODUCT HIGHLIGHT V DD V DD 4.7uF 50K I SNK SNK 0.3V Typ LX1970 V OUT SRC 0.3V TYP I SRC 4.7uF 50K GND Ambient Light LL XX PACKAGE ORDER INFO 11 Plastic MSOP 99 T (°C) DU 8-Pin 77 A 00 RoHS Compliant / Pb-free -40 to 85 LX1970IDU Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX1970IDU-TR) Copyright © 2007 Microsemi Page 1 Rev. 1.5b, 2008-01-25 Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

LX1970 Visible Light Sensor I N T E G R A T E D P R O D U C T S PRODUCTION DATA SHEET ABSOLUTE MAXIMUM RATINGS PACKAGE PIN OUT W W V .................................................................................................................-0.3 to 6 V DD DC W SNK/SRC (Output Compliance Voltage)...........................................-0.3 to V + 0.3V VDD 1 8 VSS DD DC . SNK/SRC (Maximum Output Current)...................................................Internally Limited M NC 2 7 NC Operating Temperature Range........................................................................-40 to +85°C ic Storage Temperature Range..........................................................................-40 to +100°C NC 3 6 NC r o Solder Reflow Peak Temperature (40 seconds maximum exposure)............260°C (+0, -5) SRC 4 5 SNK s e Notes: Exceeding these ratings could cause damage to the device. All voltages are with respect to m Ground. Currents are positive into, negative out of specified terminal. DU PACKAGE i . (Top View) C O M 8 1 7 xx 19 2 x 7 6 x 0 3 5 4 THERMAL DATA DU Plastic MSOP 8-Pin DU PACKAGE (Bottom View) THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA 206°C/W xxxx = Denotes Date Code / Lot Information THERMAL RESISTANCE-JUNCTION TO CASE, θJC 39°C/W RoHS / Pb-free N iPdAu Pin Finish MSL 2 / 260°C / 1 Year FUNCTIONAL PIN DESCRIPTION NAME DESCRIPTION V Input Supply Voltage DD V Ground Reference for Power and Signal Output SS SNK Output Current Sink SRC Output Current Source SIMPLIFIED BLOCK DIAGRAM PACKAGE PHOTO V DD PP SNK AA CC KK AA GG EE SRC D D AA TT AA V SS Copyright © 2007 Microsemi Page 2 Rev. 1.5b, 2008-01-25 Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

LX1970 Visible Light Sensor I N T E G R A T E D P R O D U C T S PRODUCTION DATA SHEET RECOMMENDED OPERATING CONDITIONS W LX1970 W Parameter Units Min Typ Max W . M Supply Voltage (VDD ) 2¹ 5.5 V ic r SNK Compliance Voltage Range VSS +0.5 VDD V o s SRC Compliance Voltage Range VSS VDD - 0.5 V e m SNK/SRC Output Resistor Range 10 1000 KΩ Note 1: SRC output will work down to VDD=1.8V i .C O M ELECTRICAL CHARACTERISTICS Unless otherwise specified, the following specifications apply over the operating ambient temperature -40°C≤ T ≤ 85°C, V = 2V to A DD 5.5V, R = 50Kohms, Direct Light Input² of 14.6µW/cm2 except where otherwise noted. Performance between -40°C and 0°C and LOAD between 70°C and 85°C are assured by design and characterization. LX1970 Parameter Symbol Test Conditions Units Min Typ Max Supply Voltage Range V 2 5.5 V DD DC Input Supply Current I V = 3.0V, I = 38µA, I = open 60 85 110 µA DD DD SRC SNK I V = 3.0V 30 38 46 µA SRC DD Output Current 3 I V = 3.0V -30 -38 -46 µA SNK DD Output SNK/SRC Current Matching I V = 3.0V 0.5 2 % MATCH DD V = 3.0V, @ 95% of nominal output SNK Minimum Compliance Voltage SNK DD V +0.3 V +0.5 V VMIN current SS SS V = 3.0V, @ 95% of nominal output SRC Maximum Compliance Voltage SRC DD V – 0.3 V – 0.5 V VMAX current DD DD SNK/SRC Output Dark Current I V = 5.5V, No Light 10 300 nA DARK DD Wavelength of Peak Sensitivity λ 520 nm PS Half Reception Angle θ ±60 deg ½ Supply Voltage Coefficient of Output PSRR V = 2V to 5.5V 2.2 5 %/V Current DD EE Sensitivity @ 540nm (peak) Irradiance current responsivity 2.6 A/(W/cm2) LL EE Current responsivity change with CC Sensitivity Change @ 910nm 4 additional direct light input of 14.6µW/cm2 -5 0 5 % of peak TT at 910nm RR Radiant Sensitive Area Photodiode area 0.369 mm2 ICIC AA Note 2: The input irradiance is supplied from a white light-emitting diode (LED) optical source adjusted to impose 14.6µW/cm2 at 555nm on the sensor’s LL surface. SS Note 3: See Figure 1 Note 4: See Figure 2 Copyright © 2007 Microsemi Page 3 Rev. 1.5b, 2008-01-25 Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

LX1970 Visible Light Sensor I N T E G R A T E D P R O D U C T S PRODUCTION DATA SHEET MEASUREMENT CIRCUIT CONFIGURATIONS W W VS VDD W VDD Current M. CSouurrrecnet A Sources ic ISNK r o LX1970 s LX1970 White IR LED % e White LED 910nm SRC m LED ISRC i . A C A O M Figure 1 – Light Current Measurement Circuit Figure 2 – IR sensitivity Measurement Circuit APPLICATION NOTES LIGHT UNITS The next step in the conversion process is to convert illuminance to luminance. The units for illuminance are lux or In converting from µW/cm2 to Nits it is necessary to lumens/m2. The units for luminance are Nits or define the light source. Nits are units for a measurement lumens/m2/steradian. Assuming the illuminance falls on a of luminance, which is the apparent brightness of an Lambertian surface which has perfect dispersion and total illuminated flat surface. µW/cm2 is a measurement of reflection, the conversion from lux to nits is 3.14 lux falling on irradiance or the measurement of electromagnetic a Lambertian reflector produces 1 Nit. Therefore 100 Lux will radiation flux both visible and invisible. The first step in produce 31.4 Nits. the conversion process is to convert irradiance to illuminance, which essentially involves running the If the photo sensor had a truly photopic response, it would irradiant flux through a photopic filter. In normal ambient produce the same output current for the same number of nits or a photopic curve is used and in dark ambient a scotopic lux, regardless of the color of the light. However, because the curve (dark adapted eye) is used. If the light is composed match is not perfect, there is still wavelength dependency of only one wavelength, a conversion chart will tell the particularly at the ends of the visible spectrum. conversion factor to convert µW/m2 to lux (lumens/m2). In the case of the LX1970 the peak photo response is at If more than one wavelength is used, the light spectrum 520nm, however depending on the light source, what the of the irradiance must be applied to the photopic filter to human eye perceives as ‘white’ light may actually be composed determine the resultant illuminance. The most sensitive of peak wavelengths of light other than 520nm. For instance a wavelength for the normal light adapted human eye is typical fluorescent lamp includes dominant light not only near 555nm. At 555nm, the conversion factor is 683 Lux = 550nm but also at 404 and 435nm. Incandescent light sources 1W/m2 = 100µW/cm2. Therefore 14.6µW/cm² = 100 lux such as standard tungsten lights generate substantial IR AA at 555nm. radiation out beyond 2000nm. PP PP LL II CC AA TT II OO NN SS Copyright © 2007 Microsemi Page 4 Rev. 1.5b, 2008-01-25 Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

LX1970 Visible Light Sensor I N T E G R A T E D P R O D U C T S PRODUCTION DATA SHEET APPLICATION INFORMATION W The LX1970 is a light sensor with a spectral response W that resembles the human visual system. It is packaged in W clear MSOP package. Microsemi also offers the LX1971 . M with the same pin out and similar supply voltage range as ic LX1970 light sensor. The LX1971 responsiveness r o however differs from that of the LX1970. In general the s LX1971 has lower sensitivity and a wider dynamic range. LX1970 Calculated SRC Full Range Response e m proTphoer tioLnXa1l 9t7o0 t heh aisn tean sriteys poofn sliigvhent efsasl linthga to ni st hed irpehcotltyo 1090000 i .C receptors. Although the gain varies depending on the 800 O A) M wavelength of the light and the direction of light, in general µ 700 for a 555nm wavelength (yellow-green), the sensitivity is: nt ( 600 e I = L×0.76µA for L < 1200 lux urr 500 OUT C 400 C The LX1970 is best suited for applications where the R 300 S light sensor is an integral part of a continuous lighting 200 control system. For example, in an LCD backlighting 100 application, the level of brightness of the backlight should 0 be adjusted in proportion to the level of ambient lighting; 0 200 400 600 800 1000 1200 the LX1970 can provide closed loop brightness control for Light (lux) this type of system. For most indoor applications, the 1200 lux saturation point of the LX1970 is usually not a limiting affect. The LX1971 is best suited for applications where the LX1970 SRC Actual SRC with 10K Resistor system must respond to external events that affect the 450 user’s ability to see clearly. For example, a sensor to turn 400 on headlights or a sensor to adjust the reflectivity of a rear view mirrors. These systems require the sensor to have A)350 dsqyunaarme irco orat nfugnec stiiomni loafr tthoe sLiXgh1t9. 7L1i kmea kthees iht uemxtarna seeynes,i ttihvee ent (µ235000 to small changes at lower light levels. The wide dynamic urr200 C range allows the LX1971 to sense the difference between C 150 twilight and daylight or sunshine and heavy cloud cover. R S100 50 The first curve shows the calculated responsiveness of the LX1970 without load resistors based on the formula 0 above. It can be used as baseline guidelines to calculate 0 200 400 600 800 1000 1200 gain setting resistors. The compliance of the current source Light (lux) output may result in premature saturation of the output AA when load resistors are added. The SRC compliance PP PP voltage is specified typically at VDD-350mV @ about 100 LL lux. The second curve shows saturation of the output with II CC V = 5V and a 10K resistor SRC to ground, above about IN AA 300uA the output becomes non-linear as it begins to TT saturate. II OO NN SS Copyright © 2007 Microsemi Page 5 Rev. 1.5b, 2008-01-25 Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

LX1970 Visible Light Sensor I N T E G R A T E D P R O D U C T S PRODUCTION DATA SHEET APPLICATION EXAMPLES W The following examples present both fully automatic The output node will actually reach 1.25V when the source W (no user input) and semi-automatic to fully manual current from the LX1970 is only about 44µA since about W override implementations. These general guidelines are 6µA of current will be contributed from R1. This assumes a . M applicable to a wide variety of potential light control high impedance input to the LED driver. In Figure 3 user ic applications. The LX1970 can be used to control the adjustable bias control has been added to allow control over r o brightness input of CCFL inverters (like Microsemi’s the minimum and maximum output voltage. This allows the s PanelMatch™ inverter family, or line of controller IC’s). user to adjust the output brightness to personal preference e m Likewise it can interface well with LED drivers like the over a limited range. The PWM input source could of course LX1990 and LX1991 sink LED drivers, or boost drivers be replaced with an equivalent DC voltage. i . C like the LX1992 and LX1993. O 3.3V or 5V In each specific application it is important to recognize M the need to correlate the sink and source current of the VDD LX1970 for the target environment and its ambient light conditions. The mechanical mounting of the sensor, light VSS SNK N/C aperture hole size, use of a light pipe or bezel are critical SRC To inverter in determining the response of the LX1970 for a given brightness input or exposure of light. 3.3V PWM LED driver R1 3.3V or 5V 40K R2 10µF controller input. 25K VDD VSS SNK N/C SRC Figure 3 To inverter brightness Figure 4 shows how a fully manual override can be quickly 3V input or LED driver R1 controller. added to the example in figure 3. In addition to the gate to R2 1C0µ1F turn on and off the LX1970, a diode has been inserted to isolate the LX1970 when it is shut down. Diable Figure 2 control The example in figure 2 shows a fully automatic CMOS VDD dimming solution with no user interaction. Choose R1 Gate VSS SNK N/C and R2 values for any desired minimum brightness and SRC slope. Choose C1 to adjust response time and filter 50/60 Hz room lighting. As an example, let’s say you wish to 3.3V generate an output voltage from 0.25V to 1.25V to drive To inverter the input of an LED driver controller. The 0.25V 60K brightness input or PWM represents the minimum LED brightness and 1.25V LED driver 30K represents the maximum. The first step would be to 10µF 30K controller. determine the ratio of R1 and R2. ⎡ 3.0V ⎤ AA R1=R2⎢⎣0.25V−1⎥⎦=11×R2 Figure 4 PP The preceding examples represent just a few of the many PP Next the value of R2 can be calculated based on the LL ways the sensor can be used. For example since there is also II maximum output source current coming from the CC a complimentary sink output a resistor from VDD to SNK LX1970 under the application’s maximum light exposure, AA could develop a voltage that could be compared (with some lets say this has been determined to be about 50µA . TT hysteresis) to a fixed reference voltage and develop a logic II Thus R2 can be calculated first order as follows: OO shutdown signal. If the application is utilizing a transflective NN R2=⎡1.25V⎤=25KΩ∴R1=11×R2=275KΩ or reflective LCD display such a signal could disable the SS ⎢⎣50µA⎥⎦ backlight or front light to the display when reaching sufficient ambient light. Copyright © 2007 Microsemi Page 6 Rev. 1.5b, 2008-01-25 Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

LX1970 Visible Light Sensor I N T E G R A T E D P R O D U C T S PRODUCTION DATA SHEET RESPONSE VS WAVELENGTH ISNK STEP RESPONSE W 16 W 14 W . 2m)12 M W/c10 ic µ r de ( 8 os u e plit 6 m Am 4 i . C 2 O 0 M 0 0.5 1 Time (Seconds) Load = 10kΩ and 1µF Photo Step = Direct Light Input of 14.6µW/cm2 SMALL SIGNAL FREQUENCY RESPONSE DARK CURRENT VS TEMP 0 0.73µW/cm2 1000 VDD=5.5V 2.63µW/cm2 -5 13.14µW/cm2 VDD=1.8V -10 100 B)-15 nA) mplitude (d---322050 k Current ( 110 A ar -35 D 0.1 -40 -45 0.01 10 100 1000 10000 100000 25 40 55 70 85 Frequency (Hz) Temperature (ºC) V = 3.0V, SNK , Three Light Levels, No Filtering DD SNK OUTPUT PSRR GAIN VS TEMP 20.00 1.15 y = 1.35E-03x + 9.64E-01 0.00 1.1 B) -20.00 C) 1.05 de (d -40.00 n(25º 1 Amplitu --8600..0000 2.63µW/cm2 Gain/Gai 00.9.59 CC HH 13.14µW/cm2 -100.00 0.85 AA RR -120.00 0.8 TT 1 10 100 1000 10000 100000 -50 0 50 100 SS Frequency (Hz) Temperature (ºC) VDD = 3.0V VDD = 3.0V Load = 10kΩ and 1µF to Ground Direct Light Input of 13.14µW/cm2 Copyright © 2007 Microsemi Page 7 Rev. 1.5b, 2008-01-25 Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

LX1970 Visible Light Sensor I N T E G R A T E D P R O D U C T S PRODUCTION DATA SHEET VERTICAL DIRECTION RESPONSE HORIZONTAL DIRECTION RESPONSE W W W . 1 M 1 ic r o s e m i . C O M SNK COMPLIANCE VS CURRENT SRC COMPLIANCE VS CURRENT 140 140 120 120 µA) 100 µA)100 nt ( nt ( e 80 e 80 urr urr ut C 60 ut C 60 utp 40 utp 40 O O 20 20 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 SNK compliance Voltage (V) Source Compliance Voltage (VDD-SRC) V = 3.0V V = 3.0V DD DD SRC CURRENT VS LIGHT (LUX) TYPICAL LOW AMBIENT RESPONSE 1.200 300 cool white A) 1.000 Incandescent µ µA) 200 nt ( 0.800 nt ( rre 0.600 e u Curr ut C 0.400 C 100 p SR Out 0.200 CC HH 0 0.000 AA 0 0.2 0.4 0.6 0.8 1 RR 0 100 200 300 TT Light Input (LUX) Ambient Light (lux) SS 85°C 75°C 55°C <25°C VDD = 5.0V; SRC = 10K & 4.7µF to GND 5V Input Copyright © 2007 Microsemi Page 8 Rev. 1.5b, 2008-01-25 Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

LX1970 Visible Light Sensor I N T E G R A T E D P R O D U C T S PRODUCTION DATA SHEET PACKAGE DIMENSIONS W DU 8-Pin Miniature Shrink Outline Package (MSOP) W W . D M ic Top View Dim MILLIMETERS INCHES ro MIN MAX MIN MAX s e A – 1.10 – 0.043 m A1 0.05 0.15 0.002 0.006 i . E1 C b 0.26 0.41 0.010 0.016 O c 0.13 0.23 0.005 0.009 M D 2.90 3.10 0.114 0.122 e 0.65 BSC 0.025 BSC E 4.75 5.05 0.187 0.198 S e E1 2.90 3.10 0.114 0.122 E L 0.41 0.71 0.016 0.028 L1 0.95 BSC 0.037 BSC A c Θ S 0.525 BSC 0.021 BSC Θ 3° 3° L1 A1 b L Side Views MILLIMETERS INCHES Dim A 0.225 0.0088 Active Area B 0.145 0.0057 Required Minimum Light footprint B Bonding / Wafer area C 0.600 0.0236 D 0.612 0.0241 Active Area A CL C P1 2.5 0.98 D Note: C is the center of the package Examination of L P1 Active Area CL 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 MM coverage of the device’s active area. EE CC HH AA NN II CC AA LL SS Copyright © 2007 Microsemi Page 9 Rev. 1.5b, 2008-01-25 Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

LX1970 Visible Light Sensor I N T E G R A T E D P R O D U C T S PRODUCTION DATA SHEET NOTES W W W . M ic r o s e m i . C O M NN OO TT EE SS 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 © 2007 Microsemi Page 10 Rev. 1.5b, 2008-01-25 Analog Mixed Signal Group 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570