PMICs from AnalogicTech extend battery life

1st August 2008

Advanced Analogic Technologies Inc., Europe

ES Admin

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Datasheet

By combining two buck converters with a low input voltage used to post-regulate the second buck converter, AnalogicTech’s AAT2782 and AAT2783 are said to extend battery life and reduce board footprint by powering both standard and the lower voltage noise sensitive circuits while maintaining high power efficiency.

The AAT2782 and AAT2783 are power management ICs (PMICs) for portable applications. The devices can be used to power both traditional power management functions and noise-sensitive circuits without compromising power efficiency.

The AAT2782 and AAT2783 operate off a 2.7V to 5.5V input range and provide three independently regulated DC outputs: two step-down converters and one low input voltage LDO. The two step-down converters on the AAT2782 deliver 1200mA and 600mA respectively, while the AAT2783 delivers 1000mA and 400mA. Both converters use current mode control to ensure fast transient response and stable operation across the entire operating range. A 1.3MHz switching frequency supports the use of small external filters.
The low input voltage LDO is optimized for low noise operation. Designed to operate off a 1.7V input, the LDO delivers up to 400mA with a -80 dB power supply rejection ratio (PSRR) and 65 microVRMS output noise with an optional bypass capacitor. The LDO’s output voltage is factory set at 1.2V.

When using the LDO to post-regulate the output of the second step-down converter to produce low-noise operation, both the AAT2782 and AAT2783 achieve efficiency levels up to 80 percent. Total quiescent current is 170 micro A for the AAT2782 and 135 micro A for the AAT2783. Both devices feature 200 micro s internal soft start and over-temperature protection.

The AAT2782 and the AAT2783 are fabricated in AnalogicTech’s proprietary ModularBCD process. Compared to linear-IC legacy fabs and generic digital CMOS foundries, ModularBCD provides more cost-effective, modular fabrication of analogue, power and mixed-signal ICs by monolithically integrating fully-isolated CMOS at multiple voltages, complementary bipolar transistors, and robust power devices. This process avoids complex and expensive techniques such as epitaxy and high-temperature diffusion. Devices manufactured in ModularBCD offer higher efficiency, smaller size and higher levels of integration than those fabricated in many other processes.

Qualified across the -40 C to +85 degrees C temperature range, the AAT2782 and AAT2783 are available in a Pb-free, 16-pin, TDFN package.