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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
Drives Two N-Channel MOSFETs
Operates from +5V or +12V V
CC
Bias
Operates from +5V Power Input
Simple Single-Loop Control Design
- Voltage-Mode PWM Control
Fast Transient Response
- High-Bandwidth Error Amplifier
- Full 0% to 100% Duty Ratio
Excellent Output Voltage Regulation
-
±
1% Over Line Voltage and Temperature
TTL Compatible 5 Bit Digital-to-Analog Output Voltage
Selection
- Wide Range - 1.3V
DC
to 3.5V
DC
- 0.1V Binary Steps from 2.1V
DC
to 3.5V
DC
- 0.05V Binary Steps from 1.3V
DC
to 2.1V
DC
Power-Good Output Voltage Monitor
Over-Voltage and Over-Current Fault Monitors
- Does Not Require Extra Current Sensing Element,
- Uses MOSFET’s R
DS(ON)
Small Converter Size
- Constant Frequency Operation
- 200kHz Free-Running Oscillator Programmable from
50kHz to 1MHz
Block Diagram
Applications
Power Supply for Pentium
, Pentium Pro, PowerPC
and Alpha Microprocessors
High-Power 5V to 3.xV DC-DC Regulators
Low-Voltage Distributed Power Supplies
Description
The RC5054A provides complete control and protection for
a DC-DC converter optimized for high-performance micro-
processor applications. It is designed to drive two N-Channel
MOSFETs in a synchronous-rectified buck topology. The
RC5054A integrates all of the control, output adjustment,
monitoring and protection functions into a single package.
The output voltage of the converter is easily adjusted and
precisely regulated. The RC5054A includes a 5-input digital-
to-analog converter (DAC) that adjusts the output voltage
from 2.1V
DC
to 3.5V
DC
in 0.1V increments and from
1.3V
DC
to 2.1V
DC
in 0.05V steps. The precision reference
and voltage-mode regulator hold the selected output voltage
to within
±
1% over temperature and line voltage variations.
RC5054A
Programmable S ync hronous DC-DC Converter
Controller for Low Voltage Mic roproc essors
D/A
CONVERTER
(DAC)
OSCILLATOR
SOFT-
REFERENCE
POWER-ON
RESET (POR)
115%
110%
90%
INHIBIT
PWM
COMPARATOR
EAMP
PGOOD
SS
PWM
OVP
RT
GND
VSEN
OCSET
VID0
VID1
VID2
VID3
FB
COMP
DACOUT
OVER-
VOLTAGE
OVER-
CURRENT
GATE
CONTROL
LOGIC
BOOT
UGATE
PHASE
200
μ
A
10
μ
A
4V
+
-
+
-
+
-
+
-
+
-
+
-
LGATE
PGND
Alpha is a trademark of Digital Equipment Corporation.
Pentium is a registered trademark of Intel Corporation.
PowerPC is a trademark of IBM Corporation.
Rev. 0.9.3