High-Efficiency, Quad-Output, Main Power-Supply Controllers for Notebook Computers
SUNNYVALE, CA-July 21, 2005-Maxim Integrated Products
(NASDAQ: MXIM) introduces the MAX8732A/MAX8733A/MAX8734A dual step-down, switch-mode power-supply (SMPS) controllers that generate the main 5V and 3.3V supplies for notebook computers. These devices offer a variety of switching frequencies for highest efficiency.
The MAX8732A/MAX8733A/MAX8734A include two pulse-width modulation (PWM) controllers, 2V to 5.5V adjustable or fixed at 5V and 3.3V. These devices feature two linear regulators providing 5V and 3.3V always-on outputs. Each linear regulator provides up to 100mA output current with automatic linear-regulator bootstrapping to the main SMPS outputs. These SMPS controllers all have on-board power-up sequencing, a power-good (PGOOD) output, digital soft-start, and internal soft-stop output discharge that prevents negative voltages on shutdown.
The MAX8732A features a 200kHz/5V and 300kHz/3.3V SMPS for highest efficiency, while the MAX8733A features 400kHz/5V and 500kHz/3.3V SMPS for "thin and light" applications. The MAX8734A
provides a pin-selectable switching frequency, allowing either 200kHz/300kHz or 400kHz/500kHz operation of the 5V/3.3V SMPSs, respectively.
Maxim's proprietary Quick-PWM™ quick-response, constant on-time PWM control scheme operates without sense resistors; it provides 100ns response to load transients while maintaining a relatively constant switching frequency. The unique ultrasonic pulse-skipping mode maintains the switching frequency above 25kHz, which eliminates noise in audio applications.
The MAX8732A/MAX8733A/MAX8734A are available in 28-pin QSOP packages. The devices are pin-for-pin upgrades to the earlier MAX1777/MAX1977/MAX1999 power-supply controllers.
The MAX8732A/MAX8733A/MAX8734A are screened for the extended-industrial temperature range (-40°C to +85°C). Prices start at $4.80 (1000-up, FOB USA).
Quick-PWM is a trademark of Maxim Integrated Products, Inc.
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