The MAX8809A/MAX8810A synchronous, 2-/3-/4-phase, step-down, current-mode controllers with integrated
dual-phase MOSFET drivers provide flexible
solutions that fully comply with Intel® VRD11/VRD10
and AMD K8 Rev F CPU core supplies. The flexible
design supplies load currents up to 150A for low-voltage
CPU core power requirements.
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.
Applications
- Desknotes and LCD PCs
- Desktop PCs
- Servers, Workstations
- Voltage-Regulator Modules
