lx1973a p roduction d ata s heet microsemi analog mixed signal group 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 1 www. microsemi . com automotive light sensor tm ? copyright ? 2005 rev. 1.2, 2009-05-26 description the lx1973a 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 lx1973a has b een 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 lx1973a 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 lx1973a can be gain scaled using one external resistor. the lx1973a 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). important: for the most current data, consult microsemi ?s website: http://www.microsemi.com protected by us patents: 6,787,757; patents pending key features ? nearly perfect best eye ? 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 product highlight v out 5v r load part lx1973a lx1973a response 0.0 1.0 2.0 3.0 4.0 0.001 0.01 0.1 1 10 100 ambient light (in lux) output (in volts) package order info dr plastic msop reversed form 8-pin du plastic msop 8-pin t a ( c) rohs compliant / pb-free rohs compliant / pb-free -40 to 85 lx1973aidr lx1973aidu note: available in tape & reel. append the lett ers ?tr? to the part number. (i.e. lx1973aidu-tr) l l x x 1 1 9 9 7 7 3 3 a a
lx1973a p roduction d ata s heet microsemi analog mixed signal group 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 2 www. microsemi . com automotive light sensor tm ? copyright ? 2005 rev. 1.2, 2009-05-26 absolute maximum ratings v dd ................................................................................................................. -0.3 to 6 v dc snk/src (output complianc e voltage)........................................... -0.3 to v dd + 0.3v dc snk/src (maximum output cu rrent)................................................... in ternally limited operating temperature range ........................................................................ - 40 to +85c storage temperature ra nge.......................................................................... -40 to +100c rohs / pb-free peak package solder reflow temperature (40 seconds maximum e xposure) .................................................................... 260 (+0, -5) notes: exceeding these ratings could cause damage to th e device. all voltages are with respect to ground. currents are positive into, ne gative out of specified terminal. thermal data dr plastic msop 8-pin reverse form thermal resistance - junction to c ase , jc 39 c/w thermal resistance - junction to a mbient , ja 206 c/w du plastic msop 8-pin thermal resistance - junction to c ase , jc 39 c/w thermal resistance - junction to a mbient , ja 206 c/w junction temperature calculation: t j = t a + (p d x ja ). the ja numbers are guidelines for the thermal performan ce of the device/pc-board system. all of the above assume no ambient airflow. functional pin description name description v dd power supply voltage v ss ground reference for power and signal output out current output bp internally connected to bonding pad. this pin can be left open or connected to v ss nc no connection pin package pin out v dd bp nc out v ss bp nc nc du p ackages (top view) 973a ywwa v dd bp nc out v ss bp nc nc p ackage m arking (bottom view) 973a ywwa v dd bp nc out v ss bp nc nc p ackage m arking (top view) v dd bp nc out v ss bp nc nc dr p ackages (bottom view) rohs / pb-free nipdau finish msl 2/260c/1 year simplified block diagram v dd v ss out pre amplifier com- pression amplifier photopic sensor with dark current cancellation figure 1 ? simplified block diagram p p a a c c k k a a g g e e d d a a t t a a
lx1973a p roduction d ata s heet microsemi analog mixed signal group 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 3 www. microsemi . com automotive light sensor tm ? copyright ? 2005 rev. 1.2, 2009-05-26 electrical characteristics unless otherwise specified, the following specifications apply over the operating ambient temperature -40 c t a 85 c except where otherwise noted and the following test conditions: see note 1, v dd =5v. lx1973a parameter symbol test conditions min typ max units operational voltage v dd 4.5 5.5 v supply current i dd ev = 1.0 lux 0.2 0.25 ma power supply rejection ratio psrr v ripple = 100mv p-p , f = 10khz; c out = 0.1f 30 35 db peak spectral response pr 580 nm infrared response ) ( i ) ( i pr dd dd e v(white) = 100 lux, e v(810nm) = 14.6w/cm 2 , note 3 -5 1 5 % light to current gain g l see application section for equation saturation current i sat 570 a radiant sensitive area 0.20 mm 2 flat top package (note 5) output current i out(0.01) e v = 0.01 lux @ 25c, note 1,2 32 36 40 a output current i out(1.0) e v = 1.0 lux, note 1,2 103 114 125 a output current i out(10) e v = 10 lux, note 1,2 183 203 223 output current i out(100) e v = 100 lux, note 1,2 320 360 400 a e v = 0 lux, t a = 20 c, note 4 450 900 dark current (equivalent lux) i out (dark) e v = 0 lux, t a = 50 c, note 4 2100 5000 lux 1.0 lux to 0.01 lux 1.5 3 sec dynamic response time (to 10% settling error point) t dr 0.01 lux to 1.0 lux 0.2 0.5 sec reverse form package (note 6) output current i out(0.01) e v = 0.01 lux @ 25c, note 1,2 32 36 40 a output current i out(1.0) e v = 1.0 lux, note 1,2 105 117 128 a output current i out(10) e v = 10 lux, note 1,2, 187 208 229 output current i out(100) e v = 100 lux, note 1,2 333 370 407 a e v = 0 lux, t a = 20 c, note 4 450 900 lux dark current (equivalent lux) i out (dark) e v = 0 lux, t a = 50 c, note 4 2100 5000 1.0 lux to 0.01 lux 1.5 3 sec dynamic response time (to 10% settling error point) t dr 0.01 lux to 1.0 lux 0.2 0.5 sec notes: 1. the input irradiance is supplied from a point source which is a white light em itting diode (led); fairchild semiconductor p art number mv8w00. 2. see figure 2. 3. see figure 3. 4. dark current equivalent lux at 0 lux: ) 10 146 ( 9 4 ? ? ? ? ? ? ? = ref out i i el 5. for flat top (du package), i ref = 5824a. 6. for reverse form (dr package): i ref = 5985a e e l l e e c c t t r r i i c c a a l l s s
lx1973a p roduction d ata s heet microsemi analog mixed signal group 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 4 www. microsemi . com automotive light sensor tm ? copyright ? 2005 rev. 1.2, 2009-05-26 test circuits part white led v dd r load out gnd v dd v out lx1973a figure 2 ? operational voltage measurement circuit white led 810nm part v dd r load out gnd v dd v out lx1973a figure 3 ? ir sensitivity measurement circuit application circuits 5v to p dac/adc part lx1973a 10k 1f lx1800 part scl scd gnd adr v dd ain ref aout 5v 2.5v lamp headlamp controller brt figure 4 ? typical application e e l l e e c c t t r r i i c c a a l l s s
lx1973a p roduction d ata s heet microsemi analog mixed signal group 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 5 www. microsemi . com automotive light sensor tm ? copyright ? 2005 rev. 1.2, 2009-05-26 applications g eneral d escription the lx1973a 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 compre ssed to provide ratio metric accuracy across several decades. the sensitivity function is: () () 25 . 0 25 . 0 ambient dark ref out e e lux i p i + = i ref = 113.8a for the flat top package i ref = 117a for the reverse flat top 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. a a p p p p l l i i c c a a t t i i o o n n s s
lx1973a p roduction d ata s heet microsemi analog mixed signal group 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 6 www. microsemi . com automotive light sensor tm ? copyright ? 2005 rev. 1.2, 2009-05-26 sensitivity dark current vs temp 0 50 100 150 200 250 300 350 400 450 500 0.001 0.01 0.1 1 10 100 1000 point source light (lux) output current (a) 100 1000 10000 100000 20 40 60 80 100 temperature (c) dark current (ulx) normalized (pre compression) 100 lux output voltage (flat top) -0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 400 600 800 1000 wavelength (nm) normalized diode response lx1973a human eye 0 1 2 3 4 5 6 02468101214 load resistor (in kilo-ohms) output voltage 4.5v 5.0v 5.5v i out step response (flat top) i out over temp @ 100 lux, 10 lux, 1 lux 50 100 150 200 250 300 350 400 450 -50 -40 -10 25 50 85 100 temperature oc i out (a) i out @ 100 lux i out @ 10 lux i out @ 1 lux load = 10k ? and 0f; photo step = direct light input of 1 lux to 0.01 lux. c c h h a a r r t t s s
lx1973a p roduction d ata s heet microsemi analog mixed signal group 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 7 www. microsemi . com automotive light sensor tm ? copyright ? 2005 rev. 1.2, 2009-05-26 package dimensions du 8-pin miniature shrink outline package (msop) a1 l e l1 b e a c top view side views pin # name 1v dd 2bp 3nc 4out 5nc 6nc 7bp 8v ss ? e d s m illimeters i nches dim min max min max a ? 1.10 ? 0.043 a1 0.05 0.15 0.002 0.006 b 0.26 0.41 0.010 0.016 c 0.13 0.23 0.005 0.009 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 e1 2.90 3.10 0.114 0.122 l 0.41 0.71 0.016 0.028 l1 0.95 bsc 0.037 bsc s 0.525 bsc 0.021 bsc ? 3 3 dr 8-pin miniature shrink outline package (msop) reversed form e a 0.12 e1 d e b a1 c ? l1 l pin # name 1v dd 2bp 3nc 4out 5nc 6nc 7bp 8v ss s m illimeters i nches dim min max min max a ? 1.10 ? 0.043 a1 0.05 0.15 0.002 0.006 b 0.26 0.41 0.010 0.016 c 0.13 0.23 0.005 0.009 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 e1 2.90 3.10 0.114 0.122 l 0.41 0.71 0.016 0.028 l1 0.95 bsc 0.037 bsc s 0.525 bsc 0.021 bsc ? 3 3 note: dimensions do not include mo ld flash or protrusions; these shall not exceed 0.155mm(.006?) on any side. lead dimension shall not include solder coverage. m m e e c c h h a a n n i i c c a a l l s s
lx1973a p roduction d ata s heet microsemi analog mixed signal group 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 8 www. microsemi . com automotive light sensor tm ? copyright ? 2005 rev. 1.2, 2009-05-26 package information package land pattern 1.02 mm ( 0.04 in.) 0.41 mm (0.016 in.) 0.65 mm (0.023 in.) 4.8 mm (0.189 in.) v dd bp nc out v ss bp nc nc du package 1.02 mm ( 0.04 in.) 0.41 mm (0.016 in.) 0.65 mm (0.023 in.) 4.8 mm (0.189 in.) v ss bp nc nc v dd bp nc out dr package m m e e c c h h a a n n i i c c a a l l s s
lx1973a p roduction d ata s heet microsemi analog mixed signal group 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 9 www. microsemi . com automotive light sensor tm ? copyright ? 2005 rev. 1.2, 2009-05-26 package tape and reel information 4mm 0.1 8mm 0.1 5.5mm 0.1 2mm 0.1 12mm 0.3 5.3mm 0.1 ? 1.55mm 0.05 ? 1.6mm 0.1 ref 3.3mm 0.1 3.3mm 0.1 1.3mm 0.1 1.0mm 0.1 0.3mm 0.05 0.15mm ref 0.4mm pin 1 du package tape and reel information 4mm 0.1 8mm 0.1 5.5mm 0.1 2mm 0.1 12mm 0.3 5.3mm 0.1 ? 1.55mm 0.05 ? 1.6mm 0.1 ref 3.3mm 0.1 3.3mm 0.1 1.3mm 0.1 1.0mm 0.1 0.3mm 0.05 0.15mm ref 0.4mm pin 1 dr package tape and reel information m m e e c c h h a a n n i i c c a a l l s s
lx1973a p roduction d ata s heet microsemi analog mixed signal group 11861 western avenue, garden grove, ca. 92841, 714-898-8121, fax: 714-893-2570 page 10 www. microsemi . com automotive light sensor tm ? copyright ? 2005 rev. 1.2, 2009-05-26 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. n n o o t t e e s s
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