MAX1549ETL Datasheet, PDF (34/35 Pages) Maxim Integrated Products – Dual, Interleaved, Fixed-Frequency Step-Down Controller with a Dynamically Adjustable Output

Dual, Interleaved, Fixed-Frequency Step-Down
Controller with a Dynamically Adjustable Output
3) Group the gate-drive components (BST_ diode and
capacitor, V_DD bypass capacitor) together near the
controller IC.
4) Make the DC-DC controller ground connections as
shown in Figures 1 and 12. These diagrams can be
viewed as having two separate ground planes:
power ground for the high-power components, and
an analog ground plane for sensitive analog com-
ponents. These separate ground planes must meet
only at a single point directly at the IC. Additionally,
a star-ground connection (centered at PGND) must
be used on the power ground plane to minimize
any crosstalk between the two controllers.
5) Connect the output power planes directly to the out-
put-filter-capacitor positive and negative terminals
with multiple vias. Place the entire DC-DC converter
circuit as close to the load as is practical.
Chip Information
TRANSISTOR COUNT: 8823
PROCESS: BiCMOS
VIA TO ANALOG
GROUND PLANE
VIA TO 5V BIAS
SUPPLY (V_DD)
VIA TO V_CC
BYPASS CAPACITOR
CONNECT THE
EXPOSED PAD TO
ANALOG GND
MAX1549
TOP LAYER
VIA TO POWER
GROUND
CONNECT GND
AND PGND TO THE
CONTROLLER AT
ONE POINT ONLY
AS SHOWN
SINGLE
N-CHANNEL
MOSFETS
INDUCTOR
KELVIN-SENSE VIAS
UNDER THE SENSE RESISTOR
(REFER TO THE EVALUATION KIT)
INDUCTOR
INPUT
C_OUT
C_OUT
OOUUTPTUPUT _T
GROUND
INPUT
C_OUT
OUTPUT
GROUND
DUAL
N-CHANNEL
MOSFET
DH
LX
DL
HIGH-POWER LAYOUT
LOW-POWER LAYOUT
Figure 12. PC Board Layout Example
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