Charger and regulator come together for handhelds

Edited by the Electronicstalk editorial team Aug 9, 2006

Power management IC combines a stand-alone Li-ion/Li-polymer battery charger and a high efficiency dual synchronous buck regulator in a low-profile DFN package.

Linear Technology has announced the LTC3552, an efficient, compact power management solution for handheld applications.

The LTC3552 includes a stand-alone Li-ion/Li-polymer battery charger and a high efficiency dual synchronous buck regulator offered in a low-profile 3 x 5mm DFN package.

The linear battery charger can deliver up to 950mA charge current from a wall adapter supply, or up to 500mA charge current from a USB supply.

stand-alone operation simplifies design, eliminating the need for an external microprocessor for charge termination.

The final float voltage is accurate to +/-1%.

The LTC3552's battery charger is equipped with a patented thermal regulation scheme that maximises the charge rate without the risk of overheating.

To preserve battery energy, it draws less than 2.5uA from the battery terminal in standby and less than 1uA in shutdown mode.

The charger is compatible with inputs up to 8V (10V maximum).

The LTC3552's integrated dual synchronous buck regulators generate adjustable output voltages from 5V to as low as 0.6V, at output currents up to 800 and 400mA.

The internal switches feature a low on-resistance range to deliver efficiencies as high as 92%, maximising battery run time.

In addition, burst mode operation optimises efficiency at light loads with quiescent current of only 40uA ( less than 1uA in shutdown).

Using a constant frequency current mode architecture, the buck regulator operates from an input voltage range of 2.5 to 5.5V, making it ideal for single-cell Li-ion/Li-polymer applications.

Its high 2.25MHz switching frequency allows the utilisation of tiny low cost capacitors and inductors less than 1mm in height.

Furthermore, the regulator is stable with ceramic output capacitors, achieving very low output voltage ripple.

The LTC3552 is available from stock in a compact low-profile (0.75mm) 5 x 3mm DFN-16 package.

Pricing starts at $2.30 each for 1000-piece quantities.