Rainbow Electronics MAX1541 - Manual (Page 44)

MAX1540/MAX1541
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. This diagram can be
viewed as having two separate ground planes:
power ground, where all the high-power compo-
nents go, and an analog ground plane for sensitive
analog components. The analog ground plane and
power ground plane must meet only at a single
point directly at the IC.
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: 8612
PROCESS: BiCMOS
Dual Step-Down Controllers with Saturation
Protection, Dynamic Output, and Linear Regulator
44 ______________________________________________________________________________________
Figure 19. PC Board Layout
INDUCTOR
C OUT
C OUT
C IN OUTPUT
INPUT
GROUND
INPUT
OUTPUT
C OUT
C
IN
GROUND
INDUCTOR
HIGH-POWER LAYOUT LOW-POWER LAYOUT
MAX1540
BOTTOM LAYER
MAX1540
TOP LAYER
DL
LX
DH
DUAL
N-CHANNEL
MOSFET
KELVIN-SENSE VIAS
UNDER THE SENSE RESISTOR
(REFER TO EVALUATION KIT)
SINGLE
N-CHANNEL
MOSFETS
VIA TO V CC PIN
VIA TO REF PIN
VIA TO REF
BYPASS CAPACITOR
VIA TO V CC
BYPASS CAPACITOR
VIA TO POWER
GROUND
CONNECT GND
AND PGND TO THE
CONTROLLER AT
ONE POINT ONLY
AS SHOWN
CONNECT THE
EXPOSED PAD TO
ANALOG GROUND