500mA step-down converter promises faster transient response

Advanced Analogic Technologies Inc. (AnalogicTech) has developed the AAT1130, a high performance 500mA monolithic step-down converter. Using a pseudo fixed-frequency architecture, the new converter offers transient response at least 2x faster than a traditional 500mA, 2MHz, PWM-mode buck converter while supporting the use of extremely small, 1?H chip-scale inductors.

Designed for mobile electronics applications, the new converter operates across a 2.7V to 5.5V input range and low quiescent current of 60?A and delivers an output between 0.6V and 1.8V.

The AAT1130 also delivers up to 500mA of maximum continuous output current. Internal MOSFET switches allow the converter to support efficiency rates up to 92 percent over a wide load range.

The AAT1130'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 1.2V, the AAT1130 can handle severe load transients from 10mA to 500mA and still maintain output voltage accuracy within ±5 percent.

Operating at a high 2.5MHz switching frequency, the new step-down converter keeps output voltage ripple low while enabling the use of small, 1mm high 0603 inductors. The new device is also available with either fixed or adjustable output regulation voltage options. In the adjustable configuration, output voltage is set with an external resistor voltage divider circuit.

To manage output voltage overshoot, the AAT1130 features internal soft start. The IC also includes over-temperature and current limit protection circuits.

"As network data rates climb and mobile products such as smart phones add a dizzying array of complex applications, transient response becomes a major obstacle to high performance," says CJ Zhang, product line VP at AnalogicTech. "By combining a unique architecture specifically tuned for fast transient response with a high switching frequency, the AAT1130 allows designers to both support rising performance requirements and reduce solution size by using compact, low profile inductors."

The AAT1130 is qualified across the -40°C to +85°C temperature range. It comes in a 2mm x 2.2mm,10-pin SC70JW package. The AAT1130 sells for $0.87 in 1,000 quantities.