FAN6520A_06 Datasheet, PDF (1/15 Pages) Fairchild Semiconductor – Single Synchronous Buck PWM Controller

FAN6520A
Single Synchronous Buck PWM Controller
October 2006
Features
■ Output Range: 0.8V to V_IN
– 0.8V Internal Reference
– ±1.5% Over Line Voltage and Temperature
■ Drives N-Channel MOSFETs
■ Simple Single-Loop Control Design
– Voltage-Mode PWM Control
■ Fast Transient Response
– High-Bandwidth Error Amplifier
– Full 0% to 100% Duty Cycle
■ Lossless, Programmable, Over-Current Protection
– Uses Upper MOSFET’s R_DS(ON)
■ Small Converter Size
– 300kHz Fixed-Frequency Oscillator
– Internal Soft-Start
– 8-Lead SOIC
Applications
■ Power Supplies for PC Subsystems and Peripherals
■ MCH, GTL, and AGP Supplies
■ Cable Modems, Set-Top Boxes, and DSL Modems
■ DSP, Memory
■ Low-Voltage Distributed Power Supplies
Description
The FAN6520A simplifies implementing a complete con-
trol and protection scheme for a DC-DC stepdown con-
verter. Designed to drive N-channel MOSFETs in a
synchro-nous buck topology, the FAN6520A integrates
the control, output adjustment, monitoring, and protec-
tion functions into a single 8-lead package.
The FAN6520A employs a single feedback loop and volt-
age-mode control with fast transient response. The out-
put voltage can be precisely regulated to as low as 0.8V,
with a maximum tolerance of ±1.5% over-temperature
and line-voltage variations. A fixed-frequency oscillator
reduces design complexity, while balancing typical appli-
cation cost. The error amplifier features a 15MHz gain-
bandwidth product and an 8V/µs slew rate, which
enables high converter bandwidth for fast transient per-
formance. The resulting PWM duty cycles range from
0% to 100%.
The IC monitors the drop across the upper MOSFET and
inhibits PWM operation appropriately to protect against
over-current conditions. This approach simplifies the
implementation and improves efficiency by eliminating
the need for a current sense resistor.
The FAN6520A is rated for operation from 0° to +70°C,
with the FAN6520AI rated from –40° to +85°C.
Ordering Information
Part Number
FAN6520AM
FAN6520AMX
FAN6520AIM
FAN6520AIMX
Temperature Range
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
Package
SOIC-8
SOIC-8
SOIC-8
SOIC-8
Packing
Rails
Tape and Reel
Rails
Tape and Reel
© 2005 Fairchild Semiconductor Corporation
FAN6520A Rev. 1.0.5
www.fairchildsemi.com