ER3110DI Datasheet, PDF (21/23 Pages) Altera Corporation – Synchronous Buck Regulator

Page 21
Layout Considerations
Proper layout of the power converter will minimize EMI and noise and insure first pass success of the design. PCB
layouts are provided in multiple formats on the Altera Enpirion web site. In addition, Figure 50 will make clear the
important points in PCB layout. In reality, PCB layout of the ER3110DI is quite simple.
A multi-layer printed circuit board with GND plane is recommended. Figure 50 shows the connections of the critical
components in the converter. Note that capacitors C_IN and C_OUT could each represent multiple physical capacitors. The
most critical connections are to tie the PGND pin to the package GND pad and then use vias to directly connect the
GND pad to the system GND plane. This connection of the GND pad to system plane insures a low impedance path
for all return current, as well as an excellent thermal path to dissipate heat. With this connection made, place the high
frequency MLCC input capacitor near the PVIN pin and use vias directly at the capacitor pad to tie the capacitor to the
system GND plane.
The boot capacitor is easily placed on the PCB side opposite the controller IC and 2 vias directly connect the capacitor
to BOOT and SW.
Place a 1µF MLCC near the AVINO pin and directly connect its return with a via to the system GND plane.
Place the feedback divider close to the FB pin and do not route any feedback components near SW or BOOT. If external
components are used for SS, COMP or FSW the same advice applies.
CCS_SSS RRF_FS_SW
CVC_PI_VN_IN
L_L1₁
CO_COU_UTT
0.47”
FIGURE 50. PRINTED CIRCUIT BOARD POWER PLANES AND ISLANDS
May 2014 Altera Corporation
10038
Enpirion Power Datasheet ER3110DI Wide PVIN 1A Synchronous Buck Regulator
May 28, 2014
Rev A