Lm3915 Calculator Updated _top_ -

R2R1=VREF1.25−1the fraction with numerator cap R sub 2 and denominator cap R sub 1 end-fraction equals the fraction with numerator cap V sub cap R cap E cap F end-sub and denominator 1.25 end-fraction minus 1

: Newer versions of these calculators often include warnings about IC overheating, especially when operating in with high supply voltages. Pros and Cons LM3915 Dot/Bar Display Driver - Protricom

Matching input signals (e.g., 0-3V, 0-12V) to the 30dB display range. Lower power consumption: Using modern efficient LEDs. Core LM3915 Formulas (Updated) lm3915 calculator updated

VREF=1.25×(1+R2R1)+(IADJ×R2)cap V sub cap R cap E cap F end-sub equals 1.25 cross open paren 1 plus the fraction with numerator cap R sub 2 and denominator cap R sub 1 end-fraction close paren plus open paren cap I sub cap A cap D cap J end-sub cross cap R sub 2 close paren Because IADJcap I sub cap A cap D cap J end-sub is exceptionally low (

This quick-lookup table provides calculated resistor values for standard peak voltages, assuming a standard target LED current of approximately 10 mA to 12 mA ( Target Full-Scale Voltage ( VREFcap V sub cap R cap E cap F end-sub R1cap R sub 1 Calculated R2cap R sub 2 Nearest Standard R2cap R sub 2 Approximate ILEDcap I sub cap L cap E cap D end-sub 0 Ω (Wire Link) 2.5V 3.3V (Modern Logic) 5.0V 9.0V 12.0V Modern Design Considerations R2R1=VREF1

R2=1200×3=3600 Ωcap R sub 2 equals 1200 cross 3 equals 3600 space cap omega The closest standard E24 resistor value is . Updated Reference Lookup Table

The adjustment pin for the reference regulator. 2. Core LM3915 Mathematical Formulas The LM3915 uses an internal Core LM3915 Formulas (Updated) VREF=1

as close to the LED forward voltage drop as possible (e.g., 3.3V to 5V) to reduce thermal stress on the IC.

If you are currently troubleshooting an active design or working on a custom board layout, let me know: What is your ? Are you running the chip in Dot or Bar mode ? What power supply voltage ( ) do you have available?