High-Efficiency / 10-Pin MAX / Step-Down Controllers
Description
19-1923; Rev 0; 1/01
High-Efficiency, 10-Pin µMAX, Step-Down Controllers for Notebooks
General Description
The MAX1762/MAX1791 PWM step-down controllers provide high efficiency, excellent transient response, and high DC output accuracy needed for stepping down high-voltage batteries to generate low-voltage CPU core, I/O, and chipset RAM supplies in notebook computers and PDAs.
Maxim’s proprietary Quick-PWM™ pulse-width modulator is a free-running constant on-time type with input feed-forward.
Its high operating frequency (300kHz) allows small external components to be utilized in PC board area-critical applications such as subnotebook computers and smart phones.
PWM operation occurs at heavy loads, and automatic switchover to pulse-skipping operation occurs at lighter loads.
The external high-side P-channel and low-side N-channel MOSFETs require no bootstrap components.
The MAX1762/ MAX1791 are simple, easy to compensate, and do not have the noise sensitivity of conventional fixed-frequency current-mode PWMs.
These devices achieve high efficiency at a reduced cost by eliminating the current-sense resistor found in traditional current-mode PWMs.
Efficiency is further enhanced by their ability to drive synchronous-rectifier MOSFETs.
The MAX1762/MAX1791 come in a 10-pin µMAX package and offer two fixed voltages (Dual Mode™) for each device, 1.
8V/2.
5V/adj (MAX1762) and 3.
3V/5.
0V/adj (MAX1791).
o High Operating Frequency (300kHz) o No Current-Sense Resistor o Accurate Current Limit o ±1% Total DC Error over Line and During Continuous Conduction o Dual Mode Fixed Output 1.
8V/2.
5V/adj (MAX1762) 3.
3V/5.
0V/adj (MAX1791) o 0.
5V to 5.
5V Output Adjust Range o 5V to 20V Input Range o Automatic Light-Load Pulse Skipping Operation o Free-Running On-Demand PWM o Foldback Mode™ UVLO o PFET/NFET Synchronous Buck o 4.
65V at 25mA Linear Regulator Output o 5µA Shutdown Supply Current o 230µA Quiescent Supply Current o 10-Pin µMAX Package
Features
MAX1762/MAX1791
Ordering Information...
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