SMALLEST STEP-DOWN DC-DC FOR 1.8V LOGIC ACHIEVES 87% PEAK EFFICIENCY WITH NO INDUCTOR
SUNNYVALE, CA—February 28, 2000—Maxim Integrated Products introduces the MAX1730, a regulated step-down charge-pump DC-DC converter that generates a fixed 1.8V, 1.9V, or adjustable output voltage from a +2.7V to +5.5V input supply. The MAX1730 does not need an inductor and uses fractional conversion techniques to create a DC-DC converter with efficiency much greater than a linear regulator. A typical application generates a 1.8V core logic supply from a lithium-ion (Li+) battery (3.6V). While an ideal linear regulator would have only 50% maximum efficiency, the MAX1730 efficiency is nearly 80%, extending battery life.
The MAX1730 operates at up to 2MHz, permitting the use of small 0.22µF flying capacitors and allowing the entire circuit to fit in just 0.05in2 (32mm2). The quiescent supply current is a low 75µA. In shutdown, the supply current drops to less than 1µA and the output disconnects from the input. A proprietary soft-start circuit prevents excessive inrush current from the input supply during startup, making the MAX1730 compatible with higher output impedance sources such as alkaline and Li+ batteries.
The MAX1730EUB comes in a very small 10-pin µMAX package, which is only 1.09mm high and half the area of an 8-pin SO. The part is guaranteed for the extended-industrial temperature range (-40°C to +85°C). Prices start from $1.45 (1000-up, FOB USA).
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