FAN5078 Datasheet, PDF (1/16 Pages) Fairchild Semiconductor – DDR/ACPI Regulator Combo

May 2006
FAN5078
DDR/ACPI Regulator Combo
Features
ƒ PWM regulator for VDDQ (2.5V or 1.8)
ƒ Linear LDO regulator generates VTT = VDDQ/2,
1.5A Peak sink/source capability
ƒ AMT / M-state support
ƒ Control to generate 5V USB
ƒ ACPI drive and control for 5V DUAL generation
ƒ 3.3V internal LDO for 3V-ALW generation
ƒ 300 kHz fixed frequency switching
ƒ R_DS(ON) current sensing or optional current sense resistor
for precision over-current detect
ƒ Internal synchronous boot diode
ƒ Common Power Good signal for all voltages
ƒ Input under-voltage lockout (UVLO)
ƒ Thermal shutdown
ƒ Latched multi-fault protection
ƒ Precision reference output for ULDO controllers
ƒ 24-pin 5 x 5 MLP package
Applications
ƒ DDR VDDQ and VTT voltage generation with ACPI
support
ƒ Desktop PC's
ƒ Servers
Description
The FAN5078 DDR memory regulator combines a high-
efficiency Pulse-Width Modulated (PWM) controller to
generate the memory supply voltage, VDDQ, and a linear
regulator to generate termination voltage (VTT).
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.
The VDDQ PWM regulator is a sampled current mode control
with external compensation to achieve fast load-transient
response and provide system design optimization.
The VTT regulator derives its reference and takes its power
from the VDDQ PWM regulator, output. The VTT termination
regulator is capable of sourcing or sinking 1.5A peak currents.
In S5 M1 mode, the VDDQ switcher, VTT regulator, and the
3.3V regulators remain on. S3 mode keeps these regulators
on, but also turns on an external P-Channel to provide 5V
USB.
A single soft-start capacitor enables controlled slew rates for
both VDDQ and 3.3V-ALW outputs.
PGOOD becomes true in S0 only after all regulators have
achieved stable outputs.
In S5 (EN = 0), the 3.3V internal LDO stays on while the other
regulators are powered down.
Ordering Information
Part Number
FAN5078MPX
Temperature Range
-10°C to 85°C
Package
MLP-24 5x5mm
Packing
Tape and Reel
© 2006 Fairchild Semiconductor Corporation
FAN5078 Rev. 1.0.0 • 05/09/06
www.fairchildsemi.com