LM3915N National Semiconductor, LM3915N Datasheet
LM3915N
Specifications of LM3915N
LM3915
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LM3915N Summary of contents
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... Directly drives TTL or CMOS Y The internal 10-step divider is floating and can be refer- Y enced to a wide range of voltages The LM3915 is rated for operation from LM3915N is available in an 18-lead molded DIP package 0V to 10V Log Display February 1995 70 C The a Note 1 Capacitor C1 is re- ...
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... Absolute Maximum Ratings If Military Aerospace specified devices are required please contact the National Semiconductor Sales Office Distributors for availability and specifications Power Dissipation (Note 5) Molded DIP(N) Supply Voltage Voltage on Output Drivers Electrical Characteristics Parameter Comparators Offset Voltage Buffer and First Comparator ...
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Electrical Characteristics (Note 1) (Continued) Parameter Output Drivers LED Current LED Current Difference (Between Largest and Smallest LED Currents) LED Current Regulation Dropout Voltage Saturation Voltage Output Leakage Each Collector Output Leakage Pins 10-18 Pin 1 Supply Current Standby Supply ...
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Typical Performance Characteristics Supply Current vs Temperature Reference Adjust Pin Current vs Temperature Input Current Beyond Signal Range (Pin 5) Total Divider Resistance vs Temperature Operating Input Bias Reference Voltage vs Current vs Temperature Temperature LED Current-Regulation LED Driver Saturation ...
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Block Diagram (Showing Simplest Application 5104 – 4 ...
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Functional Description The simplified LM3915 block diagram is included to give the general idea of the circuit’s operation A high input imped- ance buffer operates with signals from ground to 12V and is protected against reverse and overvoltage signals The ...
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Mode Pin Functional Description (Continued) DOT OR BAR MODE SELECTION The voltage at pin 9 is sensed by comparator C1 nominally referenced 100 mV) The chip is in bar mode b when pin 9 is above this ...
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Application Hints (Continued) Power dissipation especially in bar mode should be given consideration For example with a 5V supply and all LEDs programmed the driver will dissipate over 600 mW In this case resistor ...
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Application Hints (Continued) FIGURE 4 Precision Full-Wave Peak Detector CASCADING THE LM3915 To display signals dynamic range multiple LM3915s can be easily cascaded Alternatively it is possi- ble to cascade an LM3915 with LM3914s for ...
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Application Hints (Continued) FIGURE 6 Improved Circuit for 60 dB Display TIPS ON REFERENCE VOLTAGE AND LED CURRENT PROGRAMMING SINGLE LM3915 The equations in Figure 7 illustrate how to choose resistor values to set reference voltage for the simple case ...
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Application Hints (Continued) FIGURE 9 Independent Adjustment of Reference Voltage and LED Intensity for Multiple LM3915s The scheme in Figure 10 is useful when the reference and LED intensity must be adjusted independently over a wide range The R voltage ...
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Typical Applications (Continued) FIGURE 10V Log Display with Smooth Transitions This application shows that the LED supply re- quires minimal filtering See Application Hints for optional Peak or Aver- age Detector Adjust R3 for 3 dB difference ...
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Typical Applications (Continued) Indicator and Alarm Full-Scale Changes Display From Dot to Bar Optional Shunts 100 A auxiliary sink current away from LED The input to the dot bar switch may be taken from cath- odes of other LEDs Display ...
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Typical Applications (Continued) Supply current drain is only 15 mA with ten LEDs illuminated Driving Vacuum Fluorescent Display R7 thru R15 10k D1 D2 1N914 or 1N4148 Half-wave peak detector See Application Hints Low Current Bar Mode Display 14 10% ...
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Typical Applications (Continued) Full-scale causes the full bar display to flash If the junction of R1 and C1 is connected to a different LED cathode the display will flash when that LED lights and at any higher input signal Driving ...
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Typical Applications (Continued) Operating with a High Voltage Supply (Dot Mode Only) The LED currents are approximately 10 mA and the LM3915 outputs operate in saturation for minimum dissipation This point is partially regulated and decreases in voltage with temperature ...
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... See Application Hints for optional Peak or Average Detector 17 Resistor value selects exposure stop resolution Ten f stop range (1000 1) Typical supply current 5104 – 30 Connection Diagram Dual-In-Line Package TL H 5104 – 32 Top View Order Number LM3915N See NS Package Number N18A ...
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Definition of Terms Absolute Accuracy The difference between the observed threshold voltage and the ideal threshold voltage for each comparator Specified and tested with 10V across the inter- nal voltage divider so that resistor ratio matching error pre- dominates over ...
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... National does not assume any responsibility for use of any circuitry described no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications Molded Dual-In-Line Package (N) Order Number LM3915N NS Package Number N18A 2 A critical component is any component of a life ...