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under any patent or patent rights of Analog Devices.
a
ADP3163
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
Fax: 781/326-8703
www.analog.com
Analog Devices, Inc., 2001
5-Bit Programmable 2-/3-Phase
Synchronous Buck Controller
FUNCT IONAL BLOCK DIAGRAM
DAC+20%
DAC+20%
CMP
CS–
CS+
COMP
FB
g
m
PWM3
PWM1
SET
RESET
CROWBAR
PGND
PWM2
VID
DAC
VID4
VID3
VID2
VID1
VCC
REF
GND
CT
VID0
SHARE
POWER
GOOD
CMP
PWRGD
PC
3.0V
REFERENCE
UVLO
& BIAS
OSCILLATOR
2-/3-PHASE
DRIVER
LOGIC
SOFT
START
ADP3163
FEATURES
ADOPT Optimal Positioning Technology for Superior
Load Transient Response and Fewest Output
Capacitors
Complies with VRM 9.0 and Intel VR Down Guideline
with Lowest System Cost
Digitally Selectable 2- or 3-Phase Operation
at up to 500 kHz per Phase
Quad Logic-level PWM Outputs for Interface to
External High-Power Drivers
Active Current Balancing between All Output Phases
Accurate Multiple VRM Module Current Sharing
5-Bit Digitally Programmable 1.1 V to 1.85 V Output
Total Output Accuracy 0.8% Over Temperature
Current-Mode Operation
Short Circuit Protection
Enhanced Power Good Output Detects Open Outputs in
Multi-VRM Power Systems
Overvoltage Protection Crowbar Protects Microprocessors
with No Additional External Components
APPLICATIONS
Desktop PC Power Supplies for:
Intel Pentium
4 Processors
AMD Athlon Processors
VRM Modules
GE NE RAL DE SCRIPT ION
The ADP3163 is a highly efficient multiphase synchronous buck
switching regulator controller optimized for converting a 5 V or
12 V main supply into the core supply voltage required by high
performance Intel processors. The ADP3163 uses an internal
5-bit DAC to read a voltage identification (VID) code directly
from the processor, which is used to set the output voltage between
1.1 V and 1.85 V. The ADP3163 uses a current mode PWM
architecture to drive the logic-level outputs at a programmable
switching frequency that can be optimized for VRM size and
efficiency. The phase relationship of the output signals can be
programmed to provide 2- or 3-phase operation, allowing for
the construction of up to three complementary buck switching
stages. These stages share the dc output current to reduce
overall output voltage ripple. An active current balancing func-
tion ensures that all phases carry equal portions of the total load
current, even under large transient loads, to minimize the size of
the inductors.
The ADP3163 also uses a unique supplemental regulation tech-
nique called active voltage positioning (ADOPT) to enhance
load transient performance. Active voltage positioning results in
a dc/dc converter that meets the stringent output voltage specifi-
cations for high performance processors, with the minimum
number of output capacitors and smallest footprint. Unlike
voltage-mode and standard current-mode architectures, active
voltage positioning adjusts the output voltage as a function of
the load current so that it is always optimally positioned for a
system transient. The ADP3163 also provides accurate and
reliable short circuit protection, adjustable current limiting, and
an enhanced Power Good output that can detect open outputs
in any phase for single or multi-VRM systems.
The ADP3163 is specified over the commercial temperature
range of 0
°
C to 70
°
C and is available in a 20-lead TSSOP package.
ADOPT is a trademark of Analog Devices, Inc.
Pentium is a registered trademark of Intel Corporation.