MAX8770 PWM Controller IC 8770

The MAX8770/MAX8771/MAX8772 are 2/1-phase inter- leaved Quick-PWMTM step-down VID power-supply con- trollers for notebook CPUs. True out-of-phase operation reduces input ripple current requirements and output volt- age ripple while easing component selection and layout difficulties. The Quick-PWM control provides instanta- neous response to fast load current steps. Active voltage positioning reduces power dissipation and bulk output capacitance requirements and allows ideal positioning compensation for tantalum, polymer, or ceramic bulk out- put capacitors. The MAX8770/MAX8771/MAX8772 are intended for two different notebook CPU core applications: either bucking down the battery directly to create the core voltage, or else bucking down the +5V system supply. The single- stage conversion method allows this device 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 higher switching frequency provides the minimum possi- ble physical size. A slew-rate controller allows controlled transitions between VID codes, controlled soft-start and shutdown, and controlled exit from suspend. A thermistor-based temperature sensor provides a programmable thermal- fault output (VRHOT). A power-monitor output (POUT) provides an analog voltage output proportional to the power consumed by the CPU. The MAX8770/MAX8771/ MAX8772 include output undervoltage protection (UVP) and thermal protection, and the MAX8770/MAX8771 also include overvoltage protection (OVP). When any of these protection features detect a fault, the controller shuts down. A voltage-regulator power-OK (PWRGD) output indicates the output is in regulation. A clock enable (CLKEN) output provides proper system startup sequenc- ing. Additionally, the MAX8771 has a phase-good (PHASEGD) output, and the MAX8770/MAX8772 includes true differential current sense. The MAX8770/MAX8771/MAX8772 implement the Intel IMVP-6+ code set and the required IMVP-6+ control sig- nals. The MAX8770/MAX8771/MAX8772 are available in a 40-pin TQFN package. Applications IMVP-6+ Core Supply Multiphase CPU Core Supply Voltage-Positioned, Step-Down Converters Notebook/Desktop Computers Blade Servers Features ♦ Single/Dual-Phase, Quick-PWM Controller ♦ ±0.4% VOUT Accuracy Over Line, Load, and Temperature ♦ 7-Bit On-Board DAC: 0 to +1.5000V Output Adjust Range ♦ Dynamic Phase Selection Optimizes Active/Sleep Efficiency ♦ Transient Phase Overlap Reduces Output Capacitance ♦ Integrated Boost Switches ♦ Active Voltage Positioning with Adjustable Gain ♦ Programmable 200kHz to 600kHz Switching Frequency ♦ Accurate Current Balance and Current Limit ♦ Adjustable Slew-Rate Control ♦ Power-Good (PWRGD), Clock Enable (CLKEN), Power Monitor (POUT) and Thermal Fault (VRHOT) Outputs ♦ Phase Fault (PHASEGD) Output (MAX8771) ♦ Drives Large Synchronous Rectifier MOSFETs ♦ 4V to 26V Battery-Input-Voltage Range ♦ Output OV Protection (MAX8770/MAX8771) ♦ UV and Thermal-Fault Protection ♦ Power Sequencing and Timing ♦ Soft-Startup and Soft-Shutdown