A channel digital volume circuit on IC MAX5486 is shown here. MAX5486 40K digital volume / balance controller that pushbutton interface. The IC bias voltage that eliminated of an external circuitry for purpose and thereby by reduces external count. The IC has an LED indicator driver circuit be used for driving the indicator LEDs indicates level and balance level. The IC operated from or power and in pin TSSOP package. circuit on MAX5486 applied applications like personal audio systems, audio devices, home theatre systems, audio systems, audio systems etc.The right channel input is applied to the pin8 (high terminal (HR) of internal digital potentiometer of the IC) and left channel input is applied to the pin17 (high terminal (HL) of the second internal digital potentiometer of the IC). Low terminals (pin and 6) of potentiometers are shorted and connected to the mid bias voltage output (pin11) of the IC. at the buffered wiper terminal (pin10) of internal potentiometer and left channel output at the buffered wiper terminal of the second internal potentiometer of the IC. A 1uF capacitor is connected from the bias generator bypass (pin12) to ground. of this capacitor is noise bypassing. of capacitors C4 and C5 are to bypass noise from the VDD and VLOGIC sources. This improves stability and performance of the circuit.
LEDs D1 to D5 are the indicator LEDs indicates volume and balance levels. R1 to R5 limits current through the corresponding LEDs. 1M resistor R6 for activating the indicator LED drivers. LED D6 represents operation mode of IC. When it glows, the IC is in balance mode and when off, the IC in volume mode. Resistor R7 limits through LED D6. volume mode the LEDs work a bar graph indicating volume. balance mode, the centremost LED alone glows when a centred balance. mute mode, all indicator LEDs OFF.
Push button switches S1 to S4 are used for controlling the circuit. Pressing S1 push the IC into mute mode. Push button S4 used between volume mode and balance mode and LED D6 indicated it. Push button S2 and S3 are used for increasing and decreasing volume mode and shifting the balance to left and right balance mode. The Vss pin of the IC is grounded single operation circuit. Shutdown pin (pin6) is tied to the VLOGIC for disabling the shutdown . Connecting the shutdown pin to drive the IC to the shutdown mode.
The output of the MAX5486 is sufficient enough to drive high impedance headphones. For driving low impedance headphones or speakers an amplifier stage be added to the output. power dissipation of MAX5486 is 675mW and consider this point while selecting the loads.
