GENERAL DESCRIPTION

The AD7148 is designed for use with capacitance sensors implementing functions such as buttons, scroll bars, and wheels. The sensors need only one PCB layer, enabling ultrathin applications.

FEATURES

Programmable capacitance-to-digital converter (CDC)

Femtofarad (fF) resolution

8 capacitance sensor inputs

25 ms update rate, all 8 sensor inputs

No external RC components required

Automatic conversion sequencer

On-chip automatic calibration logic

Automatic compensation for environmental changes

Automatic adaptive threshold and sensitivity levels

Register map compatible with AD7143

On-chip RAM to store calibration data

I2C-compatible serial interface

Separate VDRIVE level for serial interface

Interrupt output

16-lead, 4 mm × 4 mm LFCSP

2.6 V to 3.3 V supply voltage

Low operating current

Full power mode: 1 mA

Low power mode: 21.5 μA

APPLICATIONS

Cell phones

Personal music and multimedia players

Smart handheld devices

Television, A/V, and remote controls

Gaming consoles

Digital still cameras