FAN5234_10 Datasheet, PDF (1/15 Pages) Fairchild Semiconductor – Dual Mobile-Friendly PWM / PFM Controller

November 2010
FAN5234
Dual Mobile-Friendly PWM / PFM Controller
Features
ƒ Wide Input Voltage Range for Mobile Systems:
2V to 24V
ƒ Excellent Dynamic Response with Voltage Feed-
Forward and Average-Current-Mode Control
ƒ Lossless Current Sensing on Low-Side MOSFET or
Precision Over-Current via Sense Resistor
ƒ VCC Under-Voltage Lockout
ƒ Power-Good Signal
ƒ Light-Load Hysteretic Mode Maximizes Efficiency
ƒ 300KHz or 600KHz Operation
ƒ TSSOP16 Package
Applications
ƒ Mobile PC Regulator
ƒ Handheld PC Power
Related Resources
ƒ Application Note — AN-6002 Component
Calculations and Simulation Tools for FAN5234
or FAN5236
ƒ Application Note — AN-1029 Maximum Power
Enhancement Techniques for SO-8 Power
MOSFET
Description
The FAN5234 PWM controller provides high efficiency
and regulation with an adjustable output from 0.9V to
5.5V required to power I/O, chip-sets, memory banks, or
peripherals in high-performance notebook computers,
PDAs, and internet appliances. Synchronous
rectification and hysteretic operation at light loads
contribute to a high efficiency over a wide range of
loads. The Hysteretic Mode of operation can be
disabled if PWM Mode is desired for all load levels.
Efficiency is further enhanced by using the MOSFET’s
RDS(ON) as a current-sense component.
Feed-forward ramp modulation, average current mode
control, and internal feedback compensation provide
fast response to load transients. The FAN5234 monitors
these outputs and generates a PGOOD (power-good)
signal when the soft-start is completed and the output is
within ±10% of its set point. A built-in over-voltage
protection prevents the output voltage from going above
120% of the set point. Normal operation is automatically
restored when the over-voltage conditions cease.
Under-voltage protection latches the chip off when the
output drops below 75% of its set value after the soft-
start sequence is completed. An adjustable over-current
function monitors the output current by sensing the
voltage drop across the lower MOSFET.
Ordering Information
Part Number
FAN5234MTCX
Operating
Temperature
Range
-10 to +85°C
Package
16-Lead, Thin-Shrink Small-Outline Package (TSSOP)
Packing Method
Tape and Reel
© 2004 Fairchild Semiconductor Corporation
FAN5234 • Rev. 2.0.0
www.fairchildsemi.com