Current Mode PWM Controller 25A 16-Pin QSOP

The MAX8553 is a 4.5V to 28V input-voltage, synchronous step-down controller that provides a complete power-management solution for DDR memory. The MAX8553 generates 1/2 VREFIN voltage for VTT and VTTR. The VTT and VTTR tracking voltages are maintained within 1% of 1/2 VREFIN. The MAX8554 is a 4.5V to 28V input-voltage, nontracking step-down controller with a low 0.6V feedback threshold voltage. The MAX8553/MAX8554 use Maxim"s proprietary Quick-PWM architecture for fast transient response and operate with selectable pseudo-fixed frequencies. Both controllers can operate without an external bias supply. The controllers operate in synchronous-rectification mode to ensure balanced current sourcing and sinking capability of up to 25A. The MAX8553/MAX8554 also provide up to 95% efficiency, making them ideal for server and point-of-load applications. Additionally, a low 5µA shutdown current allows for longer battery life in notebook applications. Lossless current monitoring is achieved by monitoring the low-side MOSFET"s drain-to-source voltage. The MAX8553/MAX8554 have an adjustable foldback current limit to withstand a continuous output overload and short circuit. Digital soft-start provides control of inrush current during power-up. Overvoltage protection shuts the converter down and discharges the output capacitor. The MAX8553/MAX8554 come in space-saving 16-pin QSOP packages.

• Up to 25A Output-Current Capability
• Quick-PWM Control for Fast Loop Response
• Up to 95% Efficiency
• 4.5V to 28V Input Voltage Range
• No External Bias Supply Required
• 0 to 3.6V Input REFIN Range (MAX8553)
• Automatically Sets VTT and VTTR to within ±1% of 1/2 V_REFIN- (MAX8553)
• Low 0.6V Feedback Threshold (MAX8554)
• 200kHz/300kHz/400kHz/550kHz Selectable Switching Frequencies
• Adjustable Foldback Current Limit
• Overvoltage Protection
• Digital Soft-Start