
www.fairchildsemi.com
Pentium is a registered trademark of Intel Corporation. Programmable Active Droop is a trademark of Fairchild Semiconductor.
REV. 1.0.1 8/7/01
Features
Output programmable in 25mV steps from 1.05V to
1.825V using a dynamically programmable integrated
5-bit DAC
Remote sense
Programmable Active Droop
up to 200mV
Drives N-Channel MOSFETs
Overcurrent protection using MOSFET sensing
Overvoltage protection including startup
85% efficiency typical at full load
Integrated Power Good and Enable/Soft Start functions
Meets Intel VRM8.5 specifications using minimum
number of external components
20 pin SOIC package
Applications
Power supply for Pentium
III Platforms
VRM for Pentium III processor
Programmable power supply
Description
The FAN5070 is a synchronous mode DC-DC controller IC
which provides a highly accurate, programmable output volt-
age for platforms such as the Intel Pentium III, and provides a
complete solution for all Intel VRM8.5 CPU applications,
and for other high-performance processors. The FAN5070
features remote voltage sensing, independently adjustable
current limit, and a proprietary wide-range Programmable
Active Droop
for optimal converter transient response and
VRM8.5 compliance. The FAN5070 uses a 5-bit D/A con-
verter to dynamically program the output voltage during oper-
ation from 1.05V to 1.825V in 25mV steps. The FAN5070
uses a high level of integration to deliver load currents in
excess of 28A from a 5V source with minimal external
circuitry. Synchronous-mode operation offers optimum
efficiency over the entire specified output voltage range. An
on-board precision low TC reference achieves 0.8% voltage
regulation without expensive external components. The
FAN5070 also offers integrated functions including open-
collector Power Good, Output Enable/Soft Start and current
limiting, and is available in a 20 pin SOIC package.
Block Diagram
VID3
VID2
VID1
12
VID0
GNDP
19
18
2
14
20
1
13
-
+
-
+
OSC
1.24V
Reference
Digital
Control
Power
Good
5-Bit
DAC
VID4
8 7 6 5 4
+5V
+12V
PWRGD
-
+
ENABLE/SS
VCC
GNDA
3
LODRV
HIDRV
VCCP
17
VCCA
+5V
16
15
OCL
-
+
R
D
R
S
-
+
FAN5070
High Performance Programmable Synchronous
DC-DC Controller