HIGH-EFFICIENCY, QUAD-OUTPUT, MAIN POWER-SUPPLY CONTROLLERS FOR NOTEBOOK COMPUTERS
SUNNYVALE, CA-June 3, 2002-Maxim Integrated Products introduces the MAX1777/MAX1977/MAX1999 dual main power controllers. The MAX1777/
MAX1977/MAX1999 includes two PWM controllers, adjustable from 2V to 5.5V, or fixed at 5.0V 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. The MAX1777/MAX1977/MAX1999 include on-board power-up sequencing, a power-good output, digital soft-start, and internal "soft-stop" that prevents negative voltages on shutdown.
Maxim's proprietary Quick-PWM™ quick-response, constant on-time PWM control scheme operates without sense resistors and provides 100ns response to load transients while maintaining a relatively constant switching frequency. A unique ultrasonic pulse-skipping mode maintains the switching frequency above 20kHz, which eliminates noise in audio applications. Other modes include pulse skipping, which maximizes light-load applications, and fixed-frequency PWM mode, which reduces RF interference in sensitive applications.
The MAX1777 features a 200kHz/5V SMPS and a 300kHz/3.3V SMPS for highest efficiency, while the MAX1977 features a 400kHz/5V SMPS and a 500kHz/3.3V SMPS for "thin and light" applications. The MAX1999 provides a pin-selectable switching frequency, allowing either 200kHz/300kHz or 400kHz/500kHz operation of 5.0V/3.3V SMPSs, respectively. The MAX1777/MAX1977/MAX1999 are available in 28-pin QSOP packages. All devices are screened for the extended temperature range
(-40°C to +85°C). Prices start at $4.80 (1000-up, FOB USA). To reduce design time, a preassembled evaluation kit (MAX1777EVKIT) is available with recommended external components.
Quick-PWM is a trademark of Maxim Integrated Products, Inc.
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