rt9246 Richtek Technology Corporation, rt9246 Datasheet - Page 15

• Manufacturer Part Number: rt9246
• Description: Multi-phase Controller Core Power Supply
• Manufacturer: Richtek Technology Corporation

Layout Guide
Place the high-power switching components first, and separate them from sensitive nodes.
1. Most critical path: the current sense circuit is the most sensitive part of the converter. The current sense
2. Switching ripple current path:
3. MOSFET driver should be closed to MOSFET.
4. The compensation, bypass and other function setting components should be near the IC and away from the noisy
DS9246-06 March 2007
resistors tied to ISP1,2,3 and ISN1,ISN23 should be located not more than 0.5 inch from the IC and away
from the noise switching nodes. The PCB trace of sense nodes should be parallel and as short as possible.
Kelvin connection of the sense component (additional sense resistor or MOSFET R
stable current sensing.
a. Input capacitor to high side MOSFET.
b. Low side MOSFET to output capacitor.
c. The return path of input and output capacitor.
d. Separate the power and signal GND.
e. The switching nodes (the connection node of high/low side MOSFET and inductor) is the most noisy points.
f. Reduce parasitic R, L by minimum length, enough copper thickness and avoiding of via.
power path.
Keep well Kelvin sense to ensure the stable operation!
Keep them away from sensitive small-signal node.
R
IN
V
V
IN
C
IN
Figure 7. Power Stage Ripple Current Path
SW2
SW1
L2
L1
V
OUT
C
OUT
DS(ON)
) ensures the accurate
R
L
RT9246
www.richtek.com
15