RC5051 Datasheet, PDF (1/16 Pages) Fairchild Semiconductor – Programmable Synchronous DC-DC Controller for Low Voltage Microprocessors

www.fairchildsemi.com
RC5051
Programmable Synchronous DC-DC Controller for
Low Voltage Microprocessors
Features
• Programmable output from 1.3V to 3.5V using an
integrated 5-bit DAC
• 85% efficiency typical
• Adjustable operation from 80KHz to 1MHz
• Integrated Power Good and Enable functions
• Overvoltage protection
• Overcurrent protection
• Drives N-channel MOSFETs
• 20 pin SOIC package
• Meets Intel Pentium II specifications using minimum
number of external components
Applications
• Power supply for Pentium^® II
• VRM for Pentium II processor
• Programmable step-down power supply
Description
The RC5051 is a synchronous mode DC-DC controller IC
which provides an accurate, programmable output voltage
for all Pentium II CPU applications. The RC5051 uses a
5-bit D/A converter to program the output voltage from 1.3V
to 3.5V. The RC5051 uses a high level of integration to
deliver load currents in excess of 19A from a 5V source with
minimal external circuitry. Synchronous-mode operation
offers optimum efficiency over the entire specified output
voltage range, and the internal oscillator can be programmed
from 80KHz to 1MHz for additional flexibility in choosing
external components. An on-board precision low TC refer-
ence achieves tight tolerance voltage regulation without
expensive external components. The RC5051 also offers
integrated functions including Power Good, Output Enable,
over-voltage protection and current limiting.
Block Diagram
1
OSC
+12V
RC5051
+5V
5
–
4
+
–
13
+
12
DIGITAL
+5V
CONTROL
7
VO
9
VREF ¹⁶
5-BIT
DAC
1.24V
REFERENCE
20 19 18 17 8
VID0 VID2 VID4
VID1 VID3
2
ENABLE
POWER
GOOD
3
PWRGD
65-5051-01
Pentium is a registered trademark of Intel Corporation.
REV. 1.0.4 4/2/01