FAN5099 Datasheet, PDF (1/24 Pages) Fairchild Semiconductor – Wide Frequency Synchronous Buck PWM AND LDO Controller

FAN5099 Wide Frequency Synchronous Buck
PWM & LDO Controller
Decemeber 2006
Features
■ General Purpose PWM Regulator and LDO Controller
■ Input Voltage Range: 3V to 24V
■ Output Voltage Range: 0.8V to 15V
■ V_CC
– 5V
– Shunt Regulator for 12V Operation
■ Support for Ceramic Cap on PWM Output
■ Programmable Current Limit for PWM Output
■ Wide Programmable Switching Frequency Range
(50kHz to 600kHz)
■ R_DS(ON) Current Sensing
■ Internal Synchronous Boot Diode
■ Soft-Start for both PWM and LDO
■ Multi-Fault Protection with Optional Auto-restart
■ 16-Pin TSSOP Package
Applications
■ High-Efficiency (80+) Computer Power Supplies
■ PC/Server Motherboard Peripherals
– V_CC_MCH (1.5V), V_DDQ (1.5V) and
V_{TT_GTL} (1.25V)
■ Power Supply for
– FPGA, DSP, Embedded Controllers, Graphic Card
Processor, and Communication Processors
■ High-Power DC-to-DC Converters
Related Application Notes
■ AN-6020 FAN5099 Component Calculation and
Simulation Tools
■ AN-6005 Synchronous Buck MOSFET Loss
Calculations with Excel Model
Description
The FAN5099 combines a high-efficiency pulse-width
modulated (PWM) controller and an LDO (Low DropOut)
linear regulator controller. The PWM controller is
designed to operate over a wide frequency range (50kHz
to 600kHz) to accommodate a variety of applications.
Synchronous rectification provides high efficiency over a
wide range of load currents. Efficiency is further
enhanced by using the low-side MOSFET’s R_DS(ON) to
sense current. In addition, the capability to operate at low
switching frequencies provides opportunities to boost
power supply efficiency by reducing switching losses and
gain cost savings using low-cost materials, such as pow-
dered iron cores, on the output inductor.
Both the linear and PWM regulator soft-start are con-
trolled by a single external capacitor, to limit in rush cur-
rent from the supply when the regulators are first
enabled. Current limit for PWM is also programmable.
The FAN5099’s ability to handle wide input voltage
ranges makes this controller suitable for power solutions
in a wide range of applications involving conversion input
voltages from Silver box, battery, and adapters. The
PWM regulator employs a summing-current-mode con-
trol with external compensation to achieve fast load tran-
sient response and provide system design optimization.
FAN5099 is offered in both industrial temperature grade
(-40°C to +85°C) as well as commercial temperature
grade (-10°C to +85°C).
Ordering Information
Part Number Operating Temp. Range Pb-Free Package Packing Method
FAN5099MTCX
-10°C to +85°C
Yes 16-Lead TSSOP Tape and Reel
FAN5099EMTCX
-40°C to +85°C
Yes 16-Lead TSSOP Tape and Reel
FAN5099MX
-10°C to +85°C
Yes
16-Lead SOIC
Tape and Reel
FAN5099EMX
-40°C to +85°C
Yes
16-Lead SOIC
Tape and Reel
Qty/Reel
2500
2500
2500
2500
Note: Contact Fairchild sales for availability of other package options.
© 2006 Fairchild Semiconductor Corporation
FAN5099 Rev. 1.1.3
www.fairchildsemi.com