The MAX8716/MAX8717/MAX8756/MAX8757 are dual, step-down, interleaved, fixed-frequency, switch-mode power-supply (SMPS) controllers with synchronous rectification. The MAX8716/MAX8717/MAX8756/MAX8757 are intended for main (5V/3.3V) power generation, while the MAX8756ETI+ is optimized for I/O power rails in battery-powered systems. Fixed-frequency operation with optimal interleaving minimizes input ripple current from the lowest input voltages up to the 26V maximum input. Optimal 40/60 interleaving allows the input voltage to go down to 8.3V before duty-cycle overlap occurs in 5V/3.3V applications, compared to 180° out-of-phase regulators where the duty-cycle overlap occurs when the input drops below 10V. Accurate output current limit is achieved using a sense resistor. Alternatively, power dissipation can be reduced using lossless inductor current sensing. Independent ON/OFF controls and power-good signals allow flexible power sequencing. Soft-start reduces inrush current, while soft-stop gradually ramps the output voltage down preventing negative voltage dips. A low-noise mode maintains high light-load efficiency while keeping the switching frequency out of the audible range. The MAX8716 is available in a 24-pin thin QFN package, and the MAX8717/MAX8756/MAX8757 are available in a 28-pin thin QFN package.
Feature
- Fixed Switching Frequency
- 200kHz, 300kHz, or 500kHz
- 250kHz, 300kHz, or 400kHz (MAX8756 Only)
- No Current-Sense Resistor Required
- 40/60 Optimal Interleaving
- Reduced Input-Capacitor Requirement
- Output Voltage Fixed or Adjustable Outputs (Dual Mode?)
- 3.3V/5V Fixed or 1V to 5.5V Adjustable
- 1.5V/1.8V Fixed or 1V to 2.3V Adjustable (MAX8756 Only)
- 4V to 26V Input Range
- Independently Selectable PWM, Skip, and Low-Noise Mode Operation
- Soft-Start and Soft-Stop
- 2V Precision Reference with 0.75% Accuracy
- Independent Power-Good Outputs
Applications
- 2 to 4 Li+ Cell Battery-Powered Devices
- Main or I/O Power Supplies
- Notebook and Subnotebook Computers
- PDAs and Mobile Communicators
