MAX5038/MAX5041
Dual-Phase, Parallelable, Average Current-Mode
Controllers
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Use the following equations to calculate C
CF
and C
CFF
:
PC Board Layout
Use the following guidelines to layout the switching
voltage regulator.
1) Place the V
IN
and V
CC
bypass capacitors close to
the MAX5038/MAX5041.
2) Minimize the high-current loops from the input
capacitor, upper switching MOSFET, inductor, and
output capacitor back to the input capacitor nega-
tive terminal.
3) Keep short the current loop from the lower switch-
ing MOSFET, inductor, and output capacitor and
return to the source of the lower MOSFET.
4) Place the Schottky diodes close to the lower
MOSFETs and on the same side of the PC board.
5) Keep the SGND and PGND isolated and connect
them at one single point close to the negative termi-
nal of the input filter capacitor.
6) Run the current-sense lines CS+ and CS- very
close to each other to minimize the loop area.
Similarly, run the remote voltage sense lines
SENSE+ and SENSE- close to each other. Do not
cross these critical signal lines through power cir-
cuitry. Sense the current right at the pads of cur-
rent-sense resistors.
7) Avoid long traces between the V
CC
bypass capaci-
tors, driver output of the MAX5038/MAX5041,
MOSFET gates and PGND pin. Minimize the loop
formed by the V
CC
bypass capacitors, bootstrap
diode, bootstrap capacitor, MAX5038/MAX5041,
and upper MOSFET gate.
8) Place the bank of output capacitors close to the load.
9) Distribute the power components evenly across the
board for proper heat dissipation.
10) Provide enough copper area at and around the
switching MOSFETs, inductor, and sense resistors
to aid in thermal dissipation.
11) Use at least 4oz copper to keep the trace induc-
tance and resistance to a minimum. Thin copper PC
boards can compromise efficiency since high cur-
rents are involved in the application. Also, thicker
copper conducts heat more effectively, thereby
reducing thermal impedance.
Chip Information
TRANSISTOR COUNT: 5431
PROCESS: BiCMOS
