FAN2106_09 Datasheet, PDF (13/15 Pages) Fairchild Semiconductor – 3-24V Input, 6A, High-Efficiency, Integrated Synchronous Buck Regulator

RRAMP also provides feedforward compensation for
changes in VIN. With a fixed RRAMP value, the modulator
gain increases as VIN is reduced; this could make it
difficult to compensate the loop. For low-input-voltage-
range designs (3V to 8V), RRAMP and the compensation
component values are different compared to designs
with VIN between 8V and 24V.
Application note AN-8022 (TinyCalc™) can be used to
calculate the compensation components.
Recommended PCB Layout
Good PCB layout and careful attention to temperature
rise is essential for reliable operation of the regulator.
Four-layer PCB with two-ounce copper on the top and
bottom sides and thermal vias connecting the layers are
recommended. Keep power traces wide and short to
minimize losses and ringing. Do not connect AGND to
PGND below the IC. Connect the AGND pin to PGND at
the output OR to the PGND plane.
SW
V_IN
GND
GND
V_OUT
Figure 26. Recommended PCB Layout
© 2009 Fairchild Semiconductor Corporation
FAN2106 • Rev. 1.1.0
13
www.fairchildsemi.com