Rainbow Electronics MAX8810A - Manual

19-3886; Rev 0; 10/05
General Description
The MAX8809A/MAX8810A synchronous, 2-/3-/4-
phase, step-down, current-mode controllers with inte-
grated 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-volt-
age 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 dis-
able the IC. True-differential remote output-voltage
sensing enables precise regulation at the load by elimi-
nating the effects of trace impedance in the output and
return paths. A high-accuracy DAC (
±0.4%) combined
with precision current-sense amplifiers and droop con-
trol enable the MAX8809A/MAX8810A to meet the most
stringent tolerance requirements of new-generation
high-current CPUs. These ICs use either integral or volt-
age-positioning feedback control to achieve high out-
put-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 exter-
nal 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 (RA
2 ) eliminates the tolerance
effects of the inductance and associated current-sens-
ing 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 com-
pact 2-chip solution.
Features
♦ VRD11/VRD10 and K8 Rev F Compliant
♦ 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
Applications
Desktop PCs
Servers, Workstations
Desknote and LCD PCs
Voltage-Regulator Modules
MAX8809A/MAX8810A
VRD11/VRD10, K8 Rev F 2/3/4-Phase PWM
Controllers with Integrated Dual MOSFET Drivers
________________________________________________________________ Maxim Integrated Products 1
For pricing delivery, and ordering information please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Ordering Information
+Denotes lead-free package.
Note: All parts are specified in the -40°C to +85°C extended
temperature range.
EVALUATION KIT
AVAILABLE
PART
PIN-
PACKAGE PKG
CODE
FUNCTION
MAX8809AETL+
40 Thin QFN
5mm x 5mm
T4055-1 2-/3-phase
MAX8810AETM+
48 Thin QFN
6mm x 6mm
T4866-1 2-/3-/4-phase
Pin Configurations appear at end of data sheet.
Intel is a registered trademark of Intel Corp.