FAN5233 Datasheet, PDF (1/15 Pages) Fairchild Semiconductor – System Electronics Regulator for Mobile PCs

www.fairchildsemi.com
FAN5233
System Electronics Regulator for Mobile PCs
Features
• 5.4V to 24V input voltage range
• Five regulated outputs:
• 5V @ 5A (PWM)
• 3.3V @ 5A (PWM)
• 5V @ 50mA Always On (Linear)
• 12V/Adjustable @ 120mA Boost (PWM)
• >96% efficiency
• Hysteretic mode for light loads
• PWM mode for normal loads
• Main regulators switch out of phase
• 300kHz fixed frequency switching
• RDS(ON) current sense over-current
• Reduced BOM; Max. efficiency
• Optional current sense resistor for precision over-current
detect
• Power Good signal for all voltages
• Input under-voltage lock-out (UVLO)
• Thermal shutdown
• ACPI compliant
• 24-pin TSSOP
Applications
• Notebook PCs
• Web tablets
• Battery-powered instruments
Description
The FAN5233 is a high efficiency and high precision
multiple-output voltage regulator for notebook PC and other
similar battery-powered applications. It integrates three
pulse-width modulated (PWM) switching regulator
controllers and one linear regulator to convert 5.4V-to-24V
notebook battery power into the voltage used by the circuitry
that surrounds the microprocessor in these systems.
The two primary PWM controllers in the FAN5233 use
synchronous-mode rectification to provide 3.3V and 5V at
over 5A each. They switch out-of-phase to minimize input
ripple-current. Utilization of both input and output voltage
feedback in a current-mode control allows for fast and stable
loop response over a wide range of input and output
variations. PWM control in normal operation and hysteretic
control under light load provides efficiency of greater than
95% over a wide range of input and output variations. The
third PWM controller generates 12V at 120mA. A propri-
etary technology is used for sensing of output current using
the RDS(ON) of the external MOSFETs, eliminating exter-
nal current sense resistors which saves board space and
reduces BOM cost.
One integrated linear regulator provides stand-by
ALWAYS-ON power at 5V for light (50mA) loads.
Additional FAN5233 features include over-voltage, under-
voltage, and over-current monitors and thermal shutdown
protection. A single Power-Good signal is issued when soft
start is completed and all outputs are within ±10% of their
settings.
REV. 1.0.6 1/22/02