Step-Down Converter Doubles Up Transient Response

Thanks to a pseudo-fixed-frequency architecture, the AAT1130, a 500-mA monolithic step-down converter, offers transient response that’s said to be at least twice as fast as a traditional 500-mA, 2-MHz, PWM-mode buck converter. At the same time, the AAT1130 supports the use of extremely small, 1-µH chip-scale inductors. Designed for mobile electronics applications, the new converter operates across a 2.7-V to 5.5-V input range and low quiescent current of 60 µA; it delivers an output between 0.6 V and 1.8 V. The AAT1130 delivers up to 500 mA of maximum continuous output current. Internal MOSFET switches allow the converter to support efficiency rates up to 92% over a wide load range. The converter’s architecture operates at a fixed switching frequency in steady-state operation while allowing the control circuit to react almost instantly to transients. With a programmed output voltage of 1.2 V, the AAT1130 can handle severe load transients from 10 mA to 500 mA and still maintain output voltage accuracy within ±5%. Operating at a high 2.5-MHz switching frequency, the new step-down converter keeps output voltage ripple low while enabling the use of small, 1-mm high 0603 inductors. The device is available with either fixed or adjustable output regulation voltage options. The AAT1130 is qualified across the -40ºC to +85º C temperature range. It comes in a 2 x 2.2 mm, 10-pin SC70JW package. Pricing is $0.87 each in lots of 1000. ADVANCED ANALOGIC TECHNOLOGIES INC., Santa Clara, CA. (408) 737-4600.