The AD5228 is Analog Devices’ latest 32-step-up/step-down control digital potentiometer emulating mechanical potentiometer operation. Its simple up/down control interface allows manual control with just two external pushbutton tactile switches. The AD5228 is designed with a built-in adaptive debouncer that ignores invalid bounces due to contact bounce commonly found in mechanical switches. The debouncer is adaptive, accommodating a variety of pushbutton tactile switches that generally have less than 10 ms of bounce time during contact closures. When choosing the switch, the user should consult the timing specification of the switch to ensure its suitability in an AD5228 application.

The AD5228 can increment or decrement the resistance in discrete steps or in autoscan mode. When the PU or PD button is pressed briefly (no longer than 0.6 s), the resistance of the AD5228 changes by one step. When the PU or PD button is held continuously for more than a second, the device activates the autoscan mode and changes four resistance steps per second.

The AD5228 can also be controlled digitally; its up/down features simplify microcontroller usage. The AD5228 is available in a compact thin SOT-23-8 (TSOT-8) package. The part is guaranteed to operate over the automotive temperature range of −40°C to +105°C.

The AD5228’s simple interface, small footprint, and very low cost enable it to replace mechanical potentiometers and trimmers with typically 3× improved resolution, solid-state reliability, and faster adjustment, resulting in considerable cost saving in end users’ systems.

Users who consider EEMEM potentiometers should refer to the recommendations in the Applications section.

APPLICATIONS

• Mechanical potentiometer and trimmer replacements
• LCD backlight, contrast, and brightness controls
• Digital volume control
• Portable device-level adjustments
• Electronic front panel-level controls
• Programmable power supply