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P
PRELIMINARY INFORMATION
describes products that are not in full production at the time of printing. Specifications are based on design goals
and limited characterization. They may change without notice. Contact Fairchild Semiconductor for current information.
www.fairchildsemi.com
Features
High power switched-mode DC-DC controller can control
in excess of 13A
Output voltage adjustable from 1.5V to 3.6V
85% efficiency
Cumulative accuracy < 3% over line, load, and
temperature variations
Overvoltage and short circuit protection
Built-in soft start
Applications
Precision 2.xV CPU core regulator for Pentium
MMX processes
Precision 2.xV or 3.xV CPU core regulator for
AMD-K6 MMX and Cyrix 6x86MX (M2)
processors
Description
The RC5037 is a high power, switch-mode DC-DC control-
ler that provides an accurate output for high-end micropro-
cessors CPU voltage. This controller has a built-in Soft Start
feature which offers system protection during power-up by
reducing both inrush current and output overshoot. When
combined with the appropriate external circuitry, the
RC5037 can deliver load currents as high as 13A at
efficiencies as high as 88%. The RC5037 can generate out-
put voltages from 1.5V up to 3.6V using external resistors.
The RC5037 is designed to operate in a “constant on-time”
(patent pending) control mode under all load conditions. Its
accurate low TC reference eliminates the need for precision
external components in order to achieve the tight tolerance
voltage regulation required by most CPU-based applications.
Short circuit current protection is provided through the use
of a current sense resistor, while overvoltage protection is
provided internally.
Block Diagram
Feedback Control
Oscillator
Digital Logic
RC5037
1.5V
Reference
Vout for CPU Core
65-5037-01
+12V
5V
+5V
1
2
4
3
8
7
6
5
RC5037
Adjustable S witc hing Regulator
Rev. A.9.4
Pentium is a registered trademark of Intel Corporation.
MMX is a trademark of Intel Corporation.
K6 is a trademark of AMD Corporation.
6x86MX is a trademark of Cyrix Corporation.