Simplified Block Diagram
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- VRD11/VRD10 and K8 Rev F Compliant
- ±0.35% Initial Output Voltage Accuracy
- Dual Integrated Drivers with Integrated Bootstrap Diodes
- Up to 26V Input Voltage
- Adaptive Shoot-Through Protection
- Soft-Start, Soft-Stop, VRREADY Output
- Fast Load Transient Response
- Individual Phase, Fully Temperature-Compensated Cycle-by-Cycle Average Current Limit
- Current Foldback at Short Circuit
- Voltage Positioning or Integral Feedback
- Differential Remote Voltage Sensing
- Programmable Positive and Negative Offset Voltages
- 150kHz to 1.2MHz Switching Frequency per Phase
- NTC-Based, Temperature-Independent Load Line
- Precise Phase Current Sharing
- Programmable Thermal-Monitoring Output (VRHOT)
- 6A Peak MOSFET Drivers
- 0.3Ω/0.85Ω Low-Side, 0.8Ω/1.1Ω High-Side Drivers (typ)
- 40-Pin and 48-Pin Thin QFN Packages
- Desknotes and LCD PCs
- Desktop PCs
- Servers, Workstations
- Voltage-Regulator Modules
A tri-state SEL input is available to configure the VID logic for either the Intel VRD11/VRD10 or AMD K8 Rev F applications. An enable input (EN) is available to disable the IC. True-differential remote output-voltage sensing enables precise regulation at the load by eliminating the effects of trace impedance in the output and return paths. A high-accuracy DAC combined with precision current-sense amplifiers and droop control enable the MAX8809A/MAX8810A to meet the most stringent tolerance requirements of new-generation high-current CPUs. These ICs use either integral or voltage-positioning feedback control to achieve high output-voltage accuracy.
The COMP input allows for either positive or negative voltage offsets from the VID code voltage. A power-good signal (VRREADY) is provided for startup sequencing and fault annunciation. The SS/OVP pin enables the programming of the soft-start period, and provides an indication of an overvoltage condition. A soft-stop feature prevents negative voltage spikes on the output at turn-off, eliminating the need for an external Schottky clamp diode.
The MAX8809A/MAX8810A incorporate a proprietary "rapid active average" current-mode control scheme for fast and accurate transient-response performance, as well as precise load current sharing. Either the inductor DCR or a resistive current-sensing element is used for current sensing. When used with DCR sensing, rapid active current averaging (RA²) eliminates the tolerance effects of the inductance and associated current-sensing components, providing superior phase current matching, accurate current limit, and precise load-line.
The MAX8809A operates as a single-chip, 2-phase solution with integrated drivers. It also provides a 3rd-phase PWM output and easily supports 3-phase design by adding the MAX8552 high-performance driver. The MAX8810A enables up to 4-phase designs by adding the MAX8523 high-performance dual driver for a compact 2-chip solution.