COMPACT, DUAL, HIGH-EFFICIENCY BUCK CONTROLLER FOR NOTEBOOKS
SUNNYVALE, CA-December 19, 2000-Maxim Integrated Products introduces the MAX1761 dual PWM step-down controller. This regulator provides high efficiency, excellent transient response, and high DC output accuracy in an extremely compact circuit topology. These features are essential for stepping down high-voltage batteries to generate low-voltage CPU core, I/O, and chipset RAM supplies in space-critical applications such as notebook computers and smart phones.
The MAX1761 employs Maxim’s proprietary Quick-PWM quick response control scheme, which handles wide input/ouput voltage ratios with ease and provides "instant-on-response" to load transients while maintaining a relatively constant switching frequency. The regulator architecture features two complementary MOSFET output stages, which reduce component count by eliminating external bootstrap capacitors and diodes. The MAX1761 achieves high efficiency at reduced cost by measuring the voltage across the low-side MOSFET in order to sense the output current. This technique eliminates the current-sense resistor found in traditional current-mode PWMs. Efficiency is further enhanced by the regulator’s ability to drive large synchronous-rectifier MOSFETs. The dual output voltages can be preprogrammed to 1.8V and 2.5V levels, or they can be adjusted between 0.5V and 5.5V with external resistive voltage dividers.
The MAX1761 is available in a 16-pin QSOP package. All devices are screened for the extended temperature range (-40°C to +85°C). Prices start at $2.95 (1000–up FOB USA). A preassembled MAX1761EVKIT (evaluation kit) is available with recommended external components to reduce design time.
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