LM3909N ,LM3909 LED Flasher/Oscillatorapplications such as trigger and sawtoothandasmall3VratedpartwillbesuitableforanyLEDflashergenerato ..
LM390N ,LM390 1W Battery Operated Audio Power AmplifierFeaturesTV sound systemsYBattery operation YLamp driversYY1W output powerLine driversYMinimum exter ..
LM3911N ,LM3911 Temperature ControllerLM3911TemperatureControllerJune1994LM3911TemperatureControllerGeneralDescriptionThe LM3911 is a hig ..
LM3914N ,Dot/Bar Display DriverGeneral Descriptionoutputs are individual, DC regulated currents. Various effectsThe LM3914 is a mo ..
LM3914N-1 ,Dot/Bar Display DriverLM3914 Dot/Bar Display DriverFebruary 2003LM3914Dot/Bar Display DriverMuch of the display flexibili ..
LM3914N-1/NOPB ,Dot/Bar Display Driver 18-PDIP 0 to 70ELECTRICAL CHARACTERISTICS(1)Parameter Conditions Min Typ Max UnitsCOMPARATOROffset Voltage, Buffer ..
LMX2305TM ,PLLatinumTM 550 MHz Frequency Synthesizer for RF Personal CommunicationsFeaturesYRF operation up to 550 MHzThe LMX2305 is a high performance frequency synthesizerYwithanin ..
LMX2305TMX ,PLLatinumTM 550 MHz Frequency Synthesizer for RF Personal CommunicationsApplicationsate a very stable, low noise local oscillator signal.YAnalog Cellular telephone systems ..
LMX2306 ,550 MHz PLLatinum Low Power Frequency Synthesizer for RF personal CommunicationsApplicationsback tuning voltage for a voltage controlled oscillator toYPortable wireless communicat ..
LMX2306TM ,550 MHz PLLatinum Low Power Frequency Synthesizer for RF Personal CommunicationsPin Descriptions16-Pin 16-Pin Pin I/O DescriptionTSSOP CSP Name115 FL O FastLock Output. For connec ..
LMX2306TMX ,550 MHz PLLatinum Low Power Frequency Synthesizer for RF Personal CommunicationsPin Descriptions16-Pin 16-Pin Pin I/O DescriptionTSSOP CSP Name115 FL O FastLock Output. For connec ..
LMX2310USLDX ,2.5 GHz PLLatinum Ultra Low Power Frequency Synthesizer for RF Personal CommunicationsFeaturesn RF operation up to 2.5 GHzThe LMX2310/1/2/3U are high performance frequency syn-thesizers ..
LM3909N
LM3909 LED Flasher/Oscillator
TL/H/7969
LM3909
LED
Flasher/Oscillator
February 1995
LM3909 LED Flasher/Oscillator
General Description
The LM3909isa monolithic oscillator specifically designed flash Light Emitting Diodes.By usingthe timing capacitor
for voltage boost,it delivers pulsesof2or more voltstothe
LED while operatingona supplyof 1.5Vor less.The circuit inherently self-starting,and requires additionof only abat-
teryand capacitorto functionasan LED flasher.
Packagedinan 8-lead plastic mini-DIP,the LM3909willop-
erate overthe extended consumer temperature rangeof
b25§Cto a70§C.Ithas beenoptimized forlow power drain
and operation from weak batteriessothat continuous oper-
ationlife exceedsthat expected from battery rating.
Applicationis made simpleby inclusionof internal timing
resistors andan internal LED current limit resistor.As
showninthefirsttwo application circuits,the timing resis-
tors suppliedare optimizedfor nominal flashing ratesand
minimum power drainat 1.5Vand3V.
Timing capacitorswill generallybeofthe electrolytic type,
anda small 3Vratedpartwillbe suitableforany LED flasher
usinga supplyupto6V. However, when picking flash rates, shouldbe rememberedthat some electrolytics have very
broad capacitance tolerances,for example b20%to
a100%.
Features Operation over one year fromoneCsize flashlightcell Bright, high current LED pulse Minimum external parts Low cost Low voltage operation, fromjust over1Vto5V Low current drain, averages under0.5mA during
batterylife Powerful;asan oscillator directly drivesan8X speaker Wide temperature range
Applications Finding flashlightsinthe dark,or locating boat mooring
floats Salesand advertising gimmicks Emergency locators,for instanceonfire extinguishers Toys and novelties Electronic applications suchas trigger and sawtooth
generators Sirenfortoyfire engine, (combined oscillator, speaker
driver) Warning indicators poweredby 1.4Vto 200V
Schematic Diagram
Typical 1.5VFlasher
TL/H/7969–1
Connection Diagram
Dual-In-Line Package
TL/H/7969–2
TopView
Order Number LM3909N
SeeNS Package Number N08E
C1995National SemiconductorCorporation RRD-B30M115/PrintedinU.S.A.
