FAN5029 Datasheet, PDF (1/3 Pages) Fairchild Semiconductor – 8-Bit Programmable 2- to 5-Phase Synchronous Buck Controller

December 2005
FAN5029
8-Bit Programmable 2- to 5-Phase Synchronous
Buck Controller
Features
■ Selectable 2-, 3-, 4-, or 5-phase operation at up to
1 MHz per phase
■ ±8 mV worst-case differential sensing error over
temperature
■ Logic-level PWM outputs for interface to external
high-power drivers
■ Active current balancing between all output phases
■ Built-in power good/crowbar blanking supports on-the-
fly VID code changes
■ Digitally programmable 0.5 V to 1.6 V output supports
both VR10 and VR11 specifications
■ Programmable short circuit protection with program-
mable latch-off delay
Applications
■ Desktop PC/Server power supplies for next generation
Intel processors
■ VRM modules
Description
The FAN5029 is a highly efficient multi-phase synchro-
nous buck switching regulator controller optimized for
converting a 12V main supply into the core supply volt-
age required by high performance Intel processors. It
uses an internal 8-bit DAC to read voltage identification
(VID) code directly from the processor, which is used to
set the output voltage between 0.5V and 1.6V. It uses a
multi-mode PWM architecture to drive the logic-level out-
puts at a programmable switching frequency that can be
optimized for VR size and efficiency. The phase relation-
ship of the output signals can be programmed to provide
2-, 3-, 4-, or 5-phase operation, allowing for the construc-
tion of up to five complementary buck switching stages.
The FAN5029 also includes programmable no-load off-
set and slope functions to adjust the output voltage as a
function of the load current, so that it is always optimally
positioned for a system transient. The FAN5029 also pro-
vides accurate and reliable short circuit protection,
adjustable current limiting, and a delayed Power Good
output that accommodates on-the-fly output voltage
changes requested by the CPU.
FAN5029 is specified over the extended commercial
temperature range of 0°C to +85°C and is available in a
40-lead MLP package.
For more information, please contact
Ron Berthiaume at [e-mail]
Related Products
■ FAN5109MX – Dual Bootstrapped 12V MOSFET Driver
■ FAN5068 – DDR-1/DDR-2 plus ACPI Regulator Combo
■ FAN5069 – PWM and LDO Controller Combo
■ FAN6520A – Single Synchronous Buck PWM Controller
©2005 Fairchild Semiconductor Corporation
1
FAN5029 Product Brief Rev. 1.0.0
www.fairchildsemi.com