High voltage step-down converters from AnalogicTech

13th August 2008

Advanced Analogic Technologies Inc., Europe

ES Admin

0 0

Datasheet

AnalogicTech has introduced a family of high voltage, high current, non-synchronous step-down converters capable of providing high efficiency power conversion from 24V supplies. Fabricated in AnalogicTech’s proprietary high voltage Modular BCD process, these new devices offer cost savings for wireless LAN, DSL and cable modem, and set-top box designs by integrating a buck converter with a low noise low dropout regulator (LDO).

While AnalogicTech has largely focused on products for mobile electronics applications, its proprietary Modular BCD fabrication process offers unique advantages in higher voltage applications. By supporting input voltages up to 24V and combining a highly efficient non-synchronous buck converter with an LDO optimized for noise-sensitive applications, this new family of products offers designers of LAN equipment operating off a low-cost 12V adapter an ideal opportunity to boost efficiency while reducing product footprint.

Operating from an input voltage between 6.0V and 24V, the AAT1189 step-down converter is targeted at consumer electronics equipment operating from a low cost AC/DC adapter. It delivers up to 2.5A output current. A 490kHz switching frequency allows designers to use smaller filtering components and keep total solution size small. The use of voltage mode control helps optimize performance across the entire load range.

The AAT2687 and AAT2689 combine a high voltage step-down converter with a low input voltage low dropout (LDO) regulator. The buck converters on both devices operate off a 6V to 24V input and deliver a VOUT of 1.5V to 5.5V. The buck converter on the AAT2689 delivers up to 2.5A. On the AAT2687 the buck converter supplies up to 4.5A. Like the AAT1189, the AAT2687 and AAT2689 take advantage of high frequency switching to support the use of smaller external filtering components.

The AAT2687 and AAT2689 devices feature an LDO capable of delivering 600mA. The LDO offers low output noise, low quiescent current and excellent transient response. Separate enable pins allow the designer to independently control the buck converter and the LDO. Shutdown current is <15 microA.

All three devices in the product family feature internal soft start, over-temperature protection and adjustable over-current protection.

The entire product family is qualified across the -40 C to +85degrees C temperature range. The AAT1189 is available in a Pb-free, 16-pin, 3x4-mm TDFN package. The AAT2689 is also available in a Pb-free, 16-pin 3x4-mm TDFN package. The AAT2687 comes in a Pb-free, 24-pin, 4 x 5-mm TQFN package.