Simplified Block Diagram
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- VRD/VRM 10 (MAX8525)
- VRD/VRM 9.1 (MAX8524)
- Fastest Load-Transient Response
- Rapid-Active Average Current Sensing
- Better than 5% Current Balance
- Fastest Voltage Positioning
- ±0.4% Initial Output-Voltage Accuracy
- Pin-Selectable 2-/3-/4-Phase Operation
- Master-Slave 6-/8-Phase Operation
- Differential Remote Voltage Sensing
- Dynamic VID Change (MAX8525)
- Adjustable, Foldback Current Limit
- Soft-Start and Soft-Stop
- Power-Good Output
- 150kHz to 1.2MHz Switching Frequency per Phase
- 28-Lead QSOP Package
- Desknotes and LCD PCs
- Desktop Computers
- High-End Switches and Routers
- Servers and Workstations
- Voltage-Regulator Modules
The switching frequency of the MAX8524/MAX8525 is adjustable from 150kHz to 1.2MHz, permitting loop bandwidths of up to 200kHz. Peak current-mode control provides fast transient response and reduces cost. A proprietary current-sharing scheme reduces current imbalance between phases to less than 5% at full load.
The MAX8524/MAX8525 offer 0.4% initial accuracy and remote-sense functionality. Both controllers also feature programmable no-load offset and output-voltage positioning to adjust the output voltage as a function of the output current. The fast-active voltage positioning further reduces bulk output capacitors and cost.
Current-mode control also simplifies compensation with a variety of capacitors by eliminating the output-filter double pole associated with voltage-mode controllers. Both devices are compatible with electrolytic, tantalum, polymer, and ceramic capacitors. Output current sensing eliminates issues associated with controllers that use high-side current sense and ensure stable and jitter-free operation. Temperature-compensated, lossless inductor current sense eliminates the need for a current-sense resistor and further reduces cost, while maintaining voltage-positioning accuracy and reducing power dissipation.
The MAX8525 features control VID voltage transition for dynamic VID changes and eliminate both undervoltage and overvoltage overshoot. The PWRGD signal is accurate during VID code changes for the MAX8525 to avoid any false fault signal.
Adjustable foldback current-limit and overvoltage protection provide for a robust design.