Stereo Audio Taper Potentiometers

with Pushbutton Interface

12

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Mode Control,

MODE

The MAX5457 MODE input toggles between volume-

and balance-control modes. Force MODE low to toggle

between volume-control and balance-control modes.

For example, driving MODE low once while in volume-

control mode, switches the MAX5457 to balance-con-

trol mode. Driving mode low once again, switches the

MAX5457 back to volume-control mode. MODE is inter-

nally pulled high with a 50k

MAX5457 powers up in volume-control mode.

Mode Indicator, MODE_IND

MODE_IND is the volume-control and balance-control

mode indicator with an open-drain output. Connect

MODE_IND to an LED through a pullup resistor to

control mode. When the LED is off, the MAX5457 is in

tion for more detail on switching between modes.

Shutdown does not affect the state of MODE_IND.

Multiple Button Pushes

The MAX5456/MAX5457 do not respond to simultane-

ous button pushes. Pushing more than one button at the

same time stops the wipers in their present states. Only

a single button push configures the device. Additionally,

a 40ms blocking period affects all other inputs when

releasing any input forced low. The MAX5456/MAX5457

do not respond to any logic input until the blocking peri-

od ends. If multiple wiper-control buttons are pressed,

all wiper-control connections must be released before

the part will respond to further commands.

Applications Information

Stereo Volume/Balance Control

Figure 6 shows a volume/balance application using the

MAX5457. The op amp is connected in a follower (non-

inverting gain) configuration to isolate the potentiome-

ter’s wiper impedance from the load and provide drive

capability. Connect the W_ of the MAX5457 to the posi-

tive input of a noninverting gain amp. The pushbutton

potentiometers attenuate the input signals. Use the

MODE input to switch between volume-control and bal-

ance-control modes.