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PRELIMINARY INFORMATION
design goals and limited characterization. They may change without notice. Contact
describes products that are not in full production at the time of printing. Specifications are based on
Fairchild Semiconductor
for current information.
P
www.fairchildsemi.com
Features
0.5% Setpoint Accuracy
Both outputs adjustable from 1.5V to 3.6V
100mA output drivers for high current loads
Short circuit protection
Fast transient response
Low Icc current < 1mA
Factory trimmed low TC voltage reference
Drives N-Channel MOSFET, NPN or Darlington Pair
8
Lead SOIC
Applications
3.3V, 2.8V dual power supply for Pentium
Processor
Switchable single/dual power supply for Pentium
P54C/P55C flexible motherboard implementation
1.5V regulator for Pentium Pro GTL+ Bus
Adjustable dual output power supply for high current
loads
P55
Description
The RC5102, in combination with low Rds,on n-channel
MOSFETs, provides a precision low-dropout dual voltage
regulator for Pentium, Cyrix
using the 12V supply available within the motherboard of
the PC, the RC5102 achieves the high Vgs drive voltage to
minimize the Rds, on of the MOSFET for low dropout appli-
cations. Earlier designs involving p-channel MOSFETs or
pnp transistors are either too costly or provide inadequate
drop-out voltages at the high current required. Using the
RC5102, a linear conversion from 5V to 2.8V is achieved at
load currents in excess of 7A, depending upon the pass ele-
ment. The RC5102 incorporates a 50MHz operational ampli-
fier in the control path, thus optimizing transient
performance due to instantaneous load changes.. Wafer-level
trimming is used to adjust the precision of the reference to a
nominal accuracy of
±
0.5%. Improved line regulation is
achieved through the use of a bootstrapped architecture
within the bandgap reference. Overcurrent protection is
available through the use of an external sense resistor.
and Power PC
CPUs. By
Block Diagram
VREF
RC5102
OVER
CURRENT
PROTECT
V1
65-5102-01
+
I
–
+
I
–
+12V
+5V
V2
RC5102
Dual Adjustable Voltage Regulators
Rev. 0.9.1