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P
www.fairchildsemi.com
Features
5-Bit Digitally Programmable 1.8V to 3.5V Fixed Output
Voltage
Provides All Features Required by the Intel Pentium II
Processor VRM 8.2 DC/DC Converter Specification
Flags for Power Good, Over-Temperature and Over-
Voltage Fault
Output Current Exceeds 14A from a 5V Supply
Dual N-Channel MOSFET Synchronous Driver
Initial Output Accuracy:
±
1.5%
Excellent Output Accuracy:
±
2% Typ Over Line, Load
and Temperature Variations
High Efficiency: Over 95% Possible
Adjustable Current Limit Without External Sense
Resistors
Fast Transient Response
Available in SO-20 and SSOP-20 Packages
Applications
Power Supply for Pentium II, SPARC, ALPHA and
PA-RISC Microprocessors
High Power 5V to 1.8V-3.5V Regulators
Descriptions
The RC5053 is a high power, high efficiency switching regu-
lator controller optimized for 5V input to 1.8V-3.5V output
applications. It features a digitally programmable output
voltage, a precision internal reference and an internal feed-
back system that provides output accuracy of
±
1.5% at room
temperature and typically
±
2% over-temperature, load cur-
rent and line voltage shifts. The RC5053 uses a synchronous
switching architecture with two external N-channel output
devices, providing high efficiency and eliminating the need
for a high power, high cost P-channel device. Additionally, it
senses the output current across the on-resistance of the
upper N-channel MOSFET, providing an adjustable current
limit without an external low value sense resistor.
The RC5053 free-runs at 300kHz and can be synchronized to
a faster external clock if desired. It includes all the inputs and
outputs required to implement a power supply conforming to
the Intel Pentium
II Processor VRM 8.2 DC/DC Converter
Specification.
Block Diagram
Pentium is a registered trademark of Intel Corporation.
VID0
VID1
VID2
VID3
VID4
OUTEN 19
COMP
SS
PV
CC
G1
SENSE
–
+
FC
–
+
–
+
PWM
SYSTEM
R
S
DISDR
V
REF
I
SS
Q
SS
115% V
REF
V
REF
0.7V
REF
HCL MONO
MHCL
V
REF
– 5%
V
REF
+ 5%
DELAY
DAC
FB
LOGIC
MAX
–
+
MIN
–
+
ERR
–
+
g
m
I
MAX
I
MAX
I
FB
PWRGD
CC
–
+
LVC
FAULT
OT
BG
10
9
12
13
2
20
8
7
11
6
18
17
16
15
14
G2
1
RC5053
5-Bit Programmable S ync hronous S witc hing
Regulator Controller for Pentium
II Proc essor
Rev. 1.0.1