●The LM27262 is a versatile synchronous buck voltage regulator controller designed according to the Intel VRD10 Specification. It’s a fixed-frequency voltage-mode control PWM with average current modulation of the reference voltage to achieve the desired output impedance. This approach imparts a pseudo current mode behavior to the control loop. The part provides the control for a voltage regulator consisting of either 2-, 3- or 4-phases to provide power to a desktop CPU. Pulse-by-pulse phase current balancing ensures accurate current sharing. CPU core currents of over 90A can be supported without requiring significant over design of the power path. The LM27262 contains a precision 6-bit digital-to-analog converter (DAC) that uses a VID-code provided by the CPU to program the desired CPU core voltage. The regulator output voltage can be dynamically adjusted by changing the VID-code “on the fly”.
●The part is intended to provide all the specified functions laid out in the VRD-10 specification, making it as simple as possible for the user to realize a fully compliant CPU core supply for Intel’s Pentium4 and Prescott processors.
●The LM27262 is available in a 48-lead TSSOP package and in a 48-lead WQFN package.
● Compatible with “VRD10 Voltage Regulation Specification” for Intel Pentium 4 and Prescott Processors
● Supports Intel SpeedStep Technology (Geyserville-III), which Enables Real-Time Dynamic Switching of the CPU Core Voltage and the CPU Clock Frequency
● Uses External Gate Drivers (LM2724) for Maximum Layout Flexibility and Noise Immunity
● Fixed Frequency PWM Architecture
● Pin Selectable Internal or External Voltage Reference
● 0.5% Core Voltage Set-Point Accuracy when Using External Voltage Reference
● 0.9% Accurate Internal Bandgap Reference
● 2-, 3- or 4-Phase Operation
● Out-of-Phase Switching Reduces Input Ripple Current, Thereby Minimizing Input Capacitor Requirements
● VID-Code Programmable Output Voltage Range of 0.8375V through 1.6000V
● User Programmable, Low Loss, Load Line Slope
● User Programmable Standard VID Offset
● User Programmable VCORE Slew Rate
● 5V Power Rail Under Voltage Lock Out (UVLO)
● Over Voltage Protection (OVP), Under Voltage Protection (UVP), and Over Current Protection (OCP) to Defend Against Potentially Catastrophic Events
● User Programmable Fault Latch That Can Be Used to Disable the Regulator in the Event a Power System Fault
● Very Fast Transient Response
● VID-Transition Masked PWRGOOD Output
● True-Differential Current Sensing for Each Phase Ensures Accurate Load Current Sharing
● User Programmable Cycle-by-Cycle Current Limit
●## Key Specifications
● Fast Transient Response to Minimize Output Capacitor Requirements
● Shorter Design Cycles Through the Use of External Gate Drivers for Reduced Power Dissipation, Ease of PCB Layout and Reduced Noise Sensitivity
● Fully Integrated Solution. All VRD-10 Control Functions Provided by a Single Device
● Accurate Current Balancing Eliminates Need to Over Design the Power Path
● Fixed Frequency PWM Minimizes EMI Issues
● Low Input Capacitor Requirements Due to Multi-Phase Interleaving
● Fault Latching Allows Use of Smaller Power Path Components and Minimizes the Chance of Damage to the Load in the Event of a Fault
● Only Need to Buy as Many Drivers as the Design Needs while Keeping Only One Controller in Inventory
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