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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.
P
www.fairchildsemi.com
Features
>85% Efficiency
350uA quiescent current in shutdown
Fast transient response
Soft control power-up
Over-Voltage Protection
Output voltage range from 2.0V to 3.6V
Factory trimmed low TC reference voltage
Adjustable oscillator frequency
Drives N-Channel MOSFETs
16 pin SOIC package
Applications
3.3V power supply for Pentium based CPU
motherboards
3.45V power supply for AMD-K5 CPU
2.5V or 3.6V power supply for PowerPC
Description
The RC5033 is a synchronous mode DC-DC controller IC
dedicated to providing a 5V to 2.0V up to 3.6V conversion
for various types of CPU power . It can be configured in both
the synchronous and non-synchronous modes and with the
proper applications circuitry can be used to deliver load cur-
rent greater than 10 Amps. The RC5033 is designed to oper-
ate in a standard PWM control mode under heavy load
conditions and as a PFM controller in light load conditions.
Its highly accurate low TC reference eliminates the need for
precision external components in order to achieve tight
tolerance voltage regulation. Through the use of external
resistors, the RC5033 can generate accurate output voltages
from 2.0V up to 3.6V. An integrated Over-Voltage protection
function constantly monitors the output voltage and shuts
down the power to the CPU in the event of a out-of-
tolerance voltage situation, thereby protecting the CPU.
The programmable oscillator can operate from 200KHz to
greater than 1MHz to provide for flexibility in choosing
external components such as inductors, capacitors, and
Power MOSFETs.
Block Diagram
DIGITAL
CONTROL
–
+
+
–
I
VREF
65-5033-01
OSC
VREF
–
+
+
–
I
–
+
+
–
I
–
+
+
–
I
VIN
VO
RC5033
Adjustable S ync hronous DC-DC Converter
Rev. 0.9.5