MAX1712
High-Speed, Digitally Adjusted Step-Down Controllers for Notebook CPUs
Digitally Adjustable Step-Down Controller Powers 12A Mobile Processors with Only Four Output Capacitors
Part Details
- Ultra-High Efficiency
- No Current-Sense Resistor (Lossless ILIMIT)
- Quick-PWM with 100ns Load-Step Response
- ±1% VOUT Accuracy over Line and Load
- 4-Bit On-Board DAC (MAX1710)
- 5-Bit On-Board DAC (MAX1711/MAX1712)
- 0.925V to 2V Output Adjust Range (MAX1711/MAX1712)
- 2V to 28V Battery Input Range
- 200/300/400/550kHz Switching Frequency
- Remote GND and VOUT Sensing
- Over/Undervoltage Protection
- 1.7ms Digital Soft-Start
- Drive Large Synchronous-Rectifier FETs
- 2V ±1% Reference Output
- Power-Good Indicator
- Small 24-Pin QSOP Package
The MAX1710/MAX1711 step-down controllers are intended for core CPU DC-DC converters in notebook computers. They feature a triple-threat combination of 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-on-time 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.
High DC precision is ensured by a 2-wire remote-sensing scheme that compensates for voltage drops in both the ground bus and supply rail. An on-board, digital-to-analog converter (DAC) sets the output voltage in compliance with Mobile Pentium II® CPU specifications.
The MAX1710 achieves high efficiency at a reduced cost by eliminating the current-sense resistor found in traditional current-mode PWMs. Efficiency is further enhanced by an ability to drive very large synchronous-rectifier MOSFETs.
Single-stage buck conversion allows these devices to directly step down high-voltage batteries for the highest possible efficiency. Alternatively, 2-stage conversion (stepping down the +5V system supply instead of the battery) at a higher switching frequency allows the minimum possible physical size.
The MAX1710/MAX1711 are identical except that the MAX1711 have 5-bit DACs and the MAX1710 has a 4-bit DAC. Also, the MAX1711 has a fixed overvoltage protection threshold at VOUT = 2.25V and undervoltage protection at VOUT = 0.8V whereas the MAX1710 has variable thresholds that track VOUT. The MAX1711 is intended for applications where the DAC code may change dynamically.
Applications
- CPU Core DC-DC Converters
- Docking Stations
- Notebook Computers
- Single-Stage (BATT to VCORE) Converters
- Two-Stage (+5V to VCORE) Converters
Documentation
Data Sheet 1
Application Note 1
Technical Articles 2
This is the most up-to-date revision of the Data Sheet.
Evaluation Kits
Voltage-Positioning Evaluation Kit for the MAX1711
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