Advertisement

Article

Pushbutton interface chip simplifies audio control

Sunnyvale, Calif.&#8212Maxim's MAX5486 dual, 32-tap, audio controller with a simple, debounced pushbutton interface for volume and balance control eliminates the need for external bias circuitry, which ultimately saves design time, costs, and board space. A stand alone device, it does away with the need for an external microcontroller, general purpose interface (GPIO), and debounce circuitry.

The chip separately controls volume and balance. The integrated buffered wiper outputs allow the MAX5486 to connect directly to the power amplifier of the audio circuit, and an integrated bias generator provides the necessary voltage [(Vdd – Vss)/2] for unipolar input
signals.



The MAX5486's three-wire pushbutton interface
features the company's enhanced SmartWiper rapid-advance wiper-control system. SmartWiper control advances the wiper at a rate of 4 Hz when the switch is closed between 250 and 500 ms, 8 Hz when the switch is closed between 500 ms and 1 second, and 11 Hz when the switch is closed for more than 1 second. A mute function can be activated to set all wipers to maximum attenuation; when deactivated, it returns the
wipers to their previous position.

A shutdown feature sets the wipers to maximum attenuation and disconnects a potentiometer's high terminal (H_) from the signal path. Deactivating the shutdown function returns the wipers to their previous position. Each channel includes integrated suppression circuitry that ensures “clickless” switching between wiper transitions, power-up, power-down, and mode transitions.

The MAX5486 includes an open-drain LED output
that indicates volume or balance control mode. Separate LED inputs indicate volume level or balance shift, depending on the operating mode. The device's two 40-kilohm resistor strings have a ratiometric and end-to-end temperature coefficient as low as 5 ppm/&degC, and 35 ppm/&degC, respectively.

The controller operates from a single 2.7 to 5.25-volt supply or a &plusmn2.7-volt supply. Click here to access the product datasheet. The MAX5486, available in a 6-by-5 mm, 24-pin TSSOP package, starts at $1.57 each (1000-up, FOB USA).

Maxim Integrated Products , 1-800-998-8800, www.maxim-ic.com

0 comments on “Pushbutton interface chip simplifies audio control

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.