LM3914General DescriptionFeaturesTypical ApplicationsAbsolute Maximum RatingsElectrical Characteristics (Notes , ) Definition of TermsTypical Performance CharacteristicsBlock DiagramFunctional DescriptionINTERNAL VOLTAGE REFERENCECURRENT PROGRAMMINGMODE PIN USEMode Pin Functional DescriptionDOT OR BAR MODE SELECTIONDOT MODE CARRYOTHER DEVICE CHARACTERISTICSTypical ApplicationsApplication Example: Grading 5V RegulatorsApplication HintsAPPLICATION TIPS FOR THE LM3914 ADJUSTABLE REFERENCEGreatly Expanded Scale (Bar Mode Only)Non-Interacting Adjustments For Expanded Scale Meter (4.5V to 5V, Bar or Dot Mode)Adjusting Linearity Of Several Stacked dividersOther ApplicationsConnection DiagramsLM3914 MDC MWC Dot/Bar Display DriverDie/Wafer CharacteristicsPhysical DimensionsLM3914Dot/Bar Display DriverGeneral DescriptionThe LM3914 is a monolithic integrated circuit that sensesanalog voltage levels and drives 10 LEDs, providing a linearanalog display. A single pin changes the display from amoving dot to a bar graph. Current drive to the LEDs isregulated and programmable, eliminating the need for resis-tors. This feature is one that allows operation of the wholesystem from less than 3V.The circuit contains its own adjustable reference and accu-rate 10-step voltage divider. The low-bias-current inputbuffer accepts signals down to ground, or V−, yet needs noprotection against inputs of 35V above or below ground. Thebuffer drives 10 individual comparators referenced to theprecision divider. Indication non-linearity can thus be heldtypically to1⁄2%, even over a wide temperature range.Versatility was designed into the LM3914 so that controller,visual alarm, and expanded scale functions are easily addedon to the display system. The circuit can drive LEDs of manycolors, or low-current incandescent lamps. Many LM3914scan be “chained” to form displays of 20 to over 100 seg-ments. Both ends of the voltage divider are externally avail-able so that 2 drivers can be made into a zero-center meter.The LM3914 is very easy to apply as an analog meter circuit.A 1.2V full-scale meter requires only 1 resistor and a single3V to 15V supply in addition to the 10 display LEDs. If the 1resistor is a pot, it becomes the LED brightness control. Thesimplified block diagram illustrates this extremely simpleexternal circuitry.When in the dot mode, there is a small amount of overlap or“fade” (about 1 mV) between segments. This assures that atno time will all LEDs be “OFF”, and thus any ambiguousdisplay is avoided. Various novel displays are possible.Much of the display flexibility derives from the fact that alloutputs are individual, DC regulated currents. Various effectscan be achieved by modulating these currents. The indi-vidual outputs can drive a transistor as well as a LED at thesame time, so controller functions including “staging” controlcan be performed. The LM3914 can also act as a program-mer, or sequencer.The LM3914 is rated for operation from 0˚C to +70˚C. TheLM3914N-1 is available in an 18-lead molded (N) package.The following typical application illustrates adjusting of thereference to a desired value, and proper grounding for ac-curate operation, and avoiding oscillations.Featuresn Drives LEDs, LCDs or vacuum fluorescentsn Bar or dot display mode externally selectable by usern Expandable to displays of 100 stepsn Internal voltage reference from 1.2V to 12Vn Operates with single supply of less than 3Vn Inputs operate down to groundn Output current programmable from 2 mA to 30 mAn No multiplex switching or interaction between outputsn Input withstands±35V without damage or false outputsn LED driver outputs are current regulated,open-collectorsn Outputs can interface with TTL or CMOS logicn The internal 10-step divider is floating and can bereferenced to a wide range of voltagesFebruary 2003LM3914 Dot/Bar Display Driver© 2004 National Semiconductor Corporation DS007970 www.national.comTypical Applications0V to 5V Bar Graph Meter00797001Note: Grounding method is typical of all uses. The 2.2µF tantalum or 10 µF aluminum electrolytic capacitor is needed if leads to the LED supply are 6" orlonger.LM3914www.national.com 2Absolute Maximum Ratings (Note 1)If Military/Aerospace specified devices are required,please contact the National Semiconductor Sales Office/Distributors for availability and specifications.Power Dissipation (Note 6)Molded DIP (N) 1365 mWSupply Voltage 25VVoltage on Output Drivers 25VInput Signal Overvoltage (Note 4)±35VDivider Voltage −100 mV to V+Reference Load Current 10 mAStorage Temperature Range −55˚C to +150˚CSoldering InformationDual-In-Line PackageSoldering (10 seconds) 260˚CPlastic Chip Carrier PackageVapor Phase (60 seconds) 215˚CInfrared (15 seconds) 220˚CSee AN-450 “Surface Mounting Methods and Their Effecton Product Reliability” for other methods of solderingsurface mount devices.Electrical Characteristics (Notes 2, 4)Parameter Conditions (Note 2) Min Typ Max UnitsCOMPARATOROffset Voltage, Buffer and FirstComparator0V ≤ VRLO=VRHI≤ 12V,ILED=1mA310mVOffset Voltage, Buffer and Any OtherComparator0V ≤ VRLO=VRHI≤ 12V,ILED=1mA315mVGain (∆ILED/∆VIN)IL(REF)= 2 mA, ILED= 10 mA 3 8 mA/mVInput Bias Current (at Pin 5) 0V ≤ VIN≤ V+− 1.5V 25 100 nAInput Signal Overvoltage No Change in Display −35 35 VVOLTAGE-DIVIDERDivider Resistance Total, Pin 6 to 4 8 12 17 kΩAccuracy (Note 3) 0.5 2 %VOLTAGE REFERENCEOutput Voltage 0.1 mA ≤ IL(REF)≤ 4 mA,V+=VLED=5V1.2 1.28 1.34 VLine Regulation 3V ≤ V+≤ 18V 0.01 0.03 %/VLoad Regulation 0.1 mA ≤ IL(REF)≤ 4 mA,V+=VLED=5V0.4 2 %Output Voltage Change withTemperature0˚C ≤ TA≤ +70˚C, IL(REF)= 1 mA,V+=5V1%Adjust Pin Current 75 120 µAOUTPUT DRIVERSLED Current V+=VLED= 5V, IL(REF)= 1 mA 7 10 13 mALED Current Difference (BetweenLargest and Smallest LED Currents)VLED=5V ILED= 2 mA 0.12 0.4mAILED=20mA 1.2 3LED Current Regulation 2V ≤ VLED≤ 17V ILED= 2 mA 0.1 0.25mAILED=20mA 1 3Dropout Voltage ILED(ON)= 20 mA, VLED= 5V,∆ILED=2mA1.5 VSaturation Voltage ILED= 2.0 mA, IL(REF)= 0.4 mA 0.15 0.4 VOutput Leakage, Each Collector (Bar Mode) (Note 5) 0.1 10 µAOutput Leakage (Dot Mode) (Note 5) Pins 10–18 0.1 10 µAPin 1 60 150 450 µASUPPLY CURRENTStandby Supply Current(All Outputs Off)V+= 5V,IL(REF)= 0.2 mA2.4 4.2 mAV+= 20V,IL(REF)= 1.0 mA6.1 9.2 mALM3914www.national.com3Electrical Characteristics (Notes 2, 4) (Continued)Note 1: Absolute Maximum Ratings indicate limits beyond which damage to
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