1MHz, LOW-VOLTAGE, STEP-DOWN REGULATORS HAVE SYNCHRONOUS RECTIFICATION AND INTERNAL SWITCHES
SUNNYVALE, CA—August 16, 2000—Maxim Integrated Products introduces the MAX1742/MAX1842 PWM step-down DC-DC converters, which provide high efficiency, low-voltage outputs for notebook and subnotebook computers. These devices feature internal synchronous rectification for high efficiency and reduced component count. The internal 90-milliohm PMOS switch and 70-milliohm NMOS synchronous-rectifier switch easily deliver continuous load currents up to 1A. The MAX1742 has a maximum current threshold of 1.3A and MAX1842 allows 3.1A. These devices achieve efficiencies as high as 95%. Both devices produce a preset +2.5V, +1.8V, or +1.5V output voltage or an adjustable output from +1.1V to VIN.
The MAX1742/MAX1842 use a unique current-mode, constant off-time, PWM control scheme, which includes an idle mode to maintain high efficiency during light-load operation. This scheme allows switching frequencies up to 1MHz, allowing the user to optimize performance trade-offs between efficiency, output switching noise, component size, and cost. The device also features an adjustable soft-start to limit surge currents during start-up, a 100% duty-cycle mode for low-dropout operation, and a low-power shutdown mode that disconnects the input from the output and reduces supply current below 1µA.
The MAX1742/MAX1842 are available in a 16-pin QSOP package and are specified for the extended industrial temperature range (-40°C to +85°C). Prices start from $3.71 (1000-up, FOB USA).
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