LM3914

SNVS761B – JANUARY 2000 – REVISED MARCH 2013

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exactly as it appears on pin 3.

Programs LEDs to 10mA

Figure 24. 20-Segment Meter with Mode Switch

APPLICATION HINTS

Three of the most commonly needed precautions for using the LM3914 are shown in the first typical application

drawing showing a 0V–5V bar graph meter. The most difficult problem occurs when large LED currents are being

drawn, especially in bar graph mode. These currents flowing out of the ground pin cause voltage drops in

external wiring, and thus errors and oscillations. Bringing the return wires from signal sources, reference ground

and bottom of the resistor string (as illustrated) to a single point very near pin 2 is the best solution.

0.05

μF to 2.2μF decoupling capacitors from LED anode common to pin 2 will damp the circuit. If LED anode line

wiring is inaccessible, often similar decoupling from pin 1 to pin 2 will be sufficient.

18

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