Low-voltage voice-coil motor driver IC with I2C interface

29th November 2007

ES Admin

0 0

The new A3904 from Allegro MicroSystems Europe is said to be the first in a series of voice-coil motor driver ICs designed for camera auto-focus and zoom applications. Featuring a built-in I2C serial interface for precise high-speed digital programming with only two control lines, the new device features an operating voltage range of 2.4 to 5.5 V and a maximum output current of 127 mA. Output current is programmed via the I2C interface in 500 µA increments with clock rates up to 400 kHz.

I2C inputs set the internal digital/analogue convertor output voltage which is used as a reference for linear current control using a MOSFET output sink transistor. The use of an internal current sense resistor and flyback current diode helps to reduce cost and save board space.

Internal protection features include thermal shutdown and under-voltage lockout. Logic input levels are independent of the supply voltage, and the operating temperature range is -40°C to +85°C. A 'sleep' mode is available to reduce the supply current to less than 0.5 µA.

The A3904 is available with three types of packaging: in a 6-contact low-profile DFN package (suffix EW) measuring only 2 x 1.5 x 0.38 mm with an exposed tab for enhanced thermal dissipation; as bare die on wafer measuring 1.1 x 0.7 x 0.33 mm (suffix CW); or in a 6-ball wafer-level chip-scale (WLCSP) bumped package (suffix CG). All package options are Pb (lead) free.