New Industry Products

Advanced Analogic Tech Step-Down Converters Convert Lithium-Ion Battery To 3.3V Out at Full Current

August 29, 2007 by Jeff Shepard

Advanced Analogic Technologies Inc. (AnalogicTech) announced the AAT1112 and AAT1145, 1.5 and 1.2A constant frequency current mode step-down converters. Available in a small 3x3mm TDFN package, these new current-mode converters require no external compensation components and are said to offer designers highly compact and easy-to-implement solutions.

"Many portable electronics devices contain circuitry that must be powered from a 3.3V rail," notes Bill Weiss, Product Line Director for AnalogicTech. "Unlike comparable voltage-mode step-down converters, the current-mode AAT1112 and AAT1145 enable a Lithium-ion battery input to a 3.3V output at full rated current. These devices are also said to minimize the size of the entire solution without forcing the system designer to iteratively determine the correct external compensation components."

The AAT1112 supplies up to 1.5A output current from a 2.4 to 5.5V input. The AAT1145 supplies up to 1.2A output current from a 2.5 to 5.5V input. Output voltage can be regulated from 0.6V to V(IN). The devices also help extend battery life by running at 100% duty cycle for low dropout operation and by offering up to 95% power efficiency.

Slope-compensated current mode PWM control enables the use of inductor values as low 1uH; while the high 1.5 and 1.4MHz switching frequency enables the use of small external components, resulting in a small total solution. The AAT1112 and AAT1145 offer integrated soft start and short-circuit and thermal fault protection. They feature a low shutdown current of < 1µA also.

Rated over the -40 to +85°C temperature range, the AAT1112 step-down converter comes in both a Pb-free, 3x3mm, 12-lead TDFN package and Pb-free, 2.75x3mm, 12-lead TSOPJW package. It sells for $1.64 each in 1,000 piece quantities in the TDFN package and $1.57 each in 1,000 piece quantities in the TSOPJW package.. The AAT1145 step-down converter comes in a Pb-free, 3x3mm, 10-lead TDFN package. It sells for $1.51 each in 1,000 piece quantities.