MAXIM MAX1854EEG

The MAX1716/MAX1854/MAX1855 step-down controllers are intended for core CPU DC-DC converters in notebook computers. They feature a dynamically adjustable output (5-bit DAC), ultra-fast transient response, high DC accuracy, and high efficiency needed for leading-edge CPU core power supplies. Maxim's proprietary Quick-PWM™ quick-response, constant-ontime PWM control scheme handles wide input/output voltage ratios with ease and provides 100ns “instant-on” response to load transients while maintaining a relatively constant switching frequency. The MAX1716/MAX1854/MAX1855 are designed specifically for CPU core applications requiring a voltage-positioned supply. The voltage-positioning input (VPS), combined with a high DC accuracy control loop, is used to implement a power supply that modifies its output set point in response to the load current. This arrangement decreases full-load power dissipation and reduces the required number of output capacitors. The 28V input range of the MAX1716/MAX1854/MAX1855 enables single-stage buck conversion from high-voltage batteries for the maximum possible efficiency. Alternatively, the devices’ high-frequency capability combined with two-stage conversion (stepping down the +5V system supply instead of the battery) allows the smallest possible physical size. The output voltage can be dynamically adjusted through the 5-bit digitalto-analog converter (DAC) inputs.

• High-Efficiency Voltage Positioning
• Quick-PWM Architecture
• ±1% VOUT Line-Regulation Accuracy
• Adjustable Output Range (5-Bit DAC) MAX1716: 0.925V to 1.6V MAX1854: 0.925V to 2.0V MAX1855: 0.600V to 1.75V
• 2V to 28V Input Range
• 200/300/400/550kHz Switching Frequency
• Output Undervoltage Protection
• Overvoltage Protection (MAX1716/MAX1855)
• Drive Large Synchronous-Rectifier MOSFETs
• 1.7ms Digital Soft-Start
• 700μA ICC Supply Current
• 1μA Shutdown Supply Current
• 2V±1% Reference Output
• VGATE Transition-Complete Indicator
• Small 24-Pin QSOP Package

• Notebook Computers
• Docking Stations
• CPU Core Supply
• Single-Stage (BATT to VCORE) Converters
• Two-Stage (+5V to VCORE) Converters