
www.fairchildsemi.com
REV. 1.0.0 6/9/03
Features
Precision Multi-Phase DC-DC Core Voltage Regulation
– ±10mV Output Voltage Accuracy Over Temperature
Differential Remote Voltage Sensing
Selectable 2, 3, or 4 Phase Operation
Up to 1MHz per Phase Operation (4MHz ripple
Frequency)
Lossless Inductor Current Sensing for Loadline
Compensation
– External Temperature Compensation
Accurate Load-Line Programming (Meets Intel
VRM/VRD10 CPU Specifications)
Accurate Channel-Current Balancing for Thermal
Optimization and Layout Compensation
Convenient 12V Supply Biasing
6-bit Voltage Identification (VID) Input
– .8375V to 1.600V in 12.5mV Steps
– Dynamic VID Capability with Fault-Blanking for
glitch-less Output voltage Changes
Adjustable Over Current Protection with Programmable
Latch-Off Delay
Over-Voltage Protection - Internal OVP Crowbar
Protection
Applications
Computer DC/DC Converter VRM/VRD10.0
Computer DC/DC Converter VRM/VRD9.X
High Current, Low Voltage DC/DC Rail
General Description
The FAN53168 is a multi-phase DC-DC controller for
implementing high-current, low-voltage, CPU core power
regulation circuits. It is part of a chipset that includes
external MOSFET drivers and power MOSFETS. The
FAN53168 drives up to 4 synchronous-rectified buck
channels in parallel. The multi-phase buck converter
architecture uses interleaved switching to multiply ripple
frequency by the number of phases and reduce input and
output ripple currents. Lower ripple results in fewer compo-
nents, lower component cost, reduced power dissipation, and
smaller board area.
The FAN53168 features a high bandwidth control loop to
provide optimal response to load transients. The FAN53168
senses current using lossless techniques: Phase current is
measured through each of the output inductors. This current
information is summed, averaged and used to set the loadline
of the output via programmable “droop”. The droop is tem-
perature compensated to achieve precise loadline character-
istics over the entire operating range. Additionally,
individual phase current is measured using the R
low-side MOSFET’s. This information is used to dynami-
cally balance/steer per-phase current. The phase currents are
also summed and averaged for over-current detection.
DS-ON
of the
Dynamic-VID technology allows on-the-fly VID changes
with controlled, glitch-less output. Additionally, short-circuit
protection, adjustable current limiting, over-voltage protec-
tion and power-good circuitry combine to ensure reliable and
safe operation. The operating temperature range is 0
+85
C and the operating voltage is a single +12V supply,
simplifying design. The FAN53168 is available in a TSSOP-
28 package.
o
C to
o
System Block Diagram
FAN53168
FAN53418
V
IN
FAN53418
V
IN
Φ
1
Φ
2
Φ
3
Φ
4
V
OUT
FAN53168
6-Bit VID Controlled 2-4 Phase DC-DC Controller