In focus

Analog Devices new AD5398 IC integrates all the functionality required to drive an auto-focus lens motor. Only simple connections are required to the battery, motor, and the processor/controller over an I2C interface.

It is also suited for use in digital still cameras, digital video cameras and security camera products, to enable applications such as lens auto-focus, image stabilization, optical zoom, shutters, and iris/exposure control.

Targeted for the mainstream camera phone market and modules with image resolution greater than 1 MP (mega pixel), the AD5398 features 120-mA output current sink capability and 10-bit resolution. In addition to a 10-bit DAC, included on chip are a current sensing resistor and inductive protection diodes.

Operating at 2.7 V to 5.5 V, the lens driver can be directly connected to a battery, so there is no need for voltage or current regulators or converters. The DAC is controlled using a 2-wire (I2C-compatible) serial interface that operates at clock rates up to 400 kHz.