MP1474 – SYNCHRONOUS STEP-DOWN CONVERTER
MP1474 Rev. 1.0 www.MonolithicPower.com 13
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PC Board Layout
(8)
PCB layout is very important to achieve stable
operation especially for VCC capacitor and
input capacitor placement. For best results,
follow these guidelines:
1. Use large ground plane directly connect to
GND pin. Add vias near the GND pin if
bottom layer is ground plane.
2. Place the VCC capacitor to VCC pin and
GND pin as close as possible. Make the
trace length of VCC pin-VCC capacitor
anode-VCC capacitor cathode-chip GND
pin as short as possible.
3. Place the ceramic input capacitor close to
IN and GND pins. Keep the connection of
input capacitor and IN pin as short and
wide as possible.
4. Route SW, BST away from sensitive
analog areas such as FB. It’s not
recommended to route SW, BST trace
under chip’s bottom side.
5. Place the T-type feedback resistor R6 close
to chip to ensure the trace which connects
to FB pin as short as possible
Notes:
8) The recommended layout is based on the Figure 7 Typical
Application circuit on the next page.
Design Example
Below is a design example following the
application guidelines for the specifications:
Table 2: Design Example
V
IN
12V
V
OUT
3.3V
Io 2A
The detailed application schematic is shown in
Figure 8. The typical performance and circuit
waveforms have been shown in the Typical
Performance Characteristics section. For more
device applications, please refer to the related
Evaluation Board Datasheets.
