FAN5099

FAN5099 Wide Frequency Synchronous Buck PWM & LDO Controller

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FAN5099 Wide Frequency Synchronous Buck PWM LDO Controller

Decemeber 2006

FAN5099 Wide Frequency Synchronous Buck PWM LDO Controller
Features
General Purpose PWM Regulator and LDO Controller Input Voltage Range: 3V to 24V Output Voltage Range: 0.8V to 15V VCC

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 RDS(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 powdered iron cores, on the output inductor. Both the linear and PWM regulator soft-start are controlled by a single external capacitor, to limit in rush current 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 wi
de range of applications involving conversion input voltages from Silver box, battery, and adapters. The PWM regulator employs a summing-current-mode control with external compensation to achieve fast load transient 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).

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) RDS(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

VCC MCH (1.5V), VDDQ (1.5V) and VTT 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

Ordering Information
Part Number
FAN5099MTCX FAN5099EMTCX FAN5099MX FAN5099EMX

Operating Temp. Range Pb-Free
-10 C to 85 C -40 C to 85 C -10 C to 85 C -40 C to 85 C Yes Yes Yes Yes

Package
16-Lead TSSOP 16-Lead TSSOP 16-Lead SOIC 16-Lead SOIC

Packing Method
Tape and Reel Tape and Reel Tape and Reel 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