lx1972 mini evaluation board 1/27/2005 microsemi rev 1.1a integrated products 11861 western avenue, garden grove ca . 92841 714-898-8121, fax: 714-893-2570 www. microsemi . com lx1972 light sensor tm ? schematic lx1972 v dd vo2 4.7uf 50k c1 r1 j1 50k c2 r2 j2 1 vo1 2 4.7uf the design of the lx1972 mini light sensor evaluation board easily interfaces to allow control of virtually any lighting requirement. changing the resistor values sets the desired minimum and maximum brightness range. as configured, there is considerable gain at lower light levels (from < 1lux to about 300lux with a 5v vdd). output voltage is ground referenced (as configured vo2) or moving the jumper from j1 to j2 changes the voltage reference to vdd at vo1. the j1 and j2 locations also allow placing a second resistor in parallel to modify the light conversion gain; this will allow a wider light range (with less overall resolution). 3v vo2 lux 300 @ 10mv vo2 dark total @ : then 5v vdd if r2 i vo2 open) j1 (if r1 i vo1 5.5v to 3v vdd src snk < = = = = protected by u.s. patents: 6,787,757; patents pending photo package pin out bc p ackage (top view) functional pin description n ame d escription v dd input supply voltage gnd ground reference for power and signal outputs 1 2 vss vdd l l x x 1 1 9 9 7 7 2 2
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