MAX17009GTL+ Maxim Integrated Products, MAX17009GTL+ Datasheet - Page 42

• Manufacturer Part Number: MAX17009GTL+
• Description: IC CTLR VIDEO SERIAL DUAL 40TQFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX17009GTL+

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

•
•
1) Place the power components first, with ground ter-
2) Mount the driver IC adjacent to the low-side
3) Group the gate-drive components (BST capacitors,
4) Make the DC-DC controller ground connections as
5) Connect the output power planes (V
AMD Mobile Serial VID Dual-Phase
Fixed-Frequency Controller
42
Keep the drivers close to the MOSFET, with the
gate-drive traces (DL, DH, LX, and BST) short and
wide to minimize trace resistance and inductance.
This is essential for high-power MOSFETs that
require low-impedance gate drivers to avoid shoot-
through currents.
When trade-offs in trace lengths must be made, it is
preferable to allow the inductor charging path to be
made longer than the discharge path. For example,
it is better to allow some extra distance between the
input capacitors and the high-side MOSFET than to
allow distance between the inductor and the low-
side MOSFET or between the inductor and the out-
put filter capacitor.
minals adjacent (low-side MOSFET source, C
C
connections on the top layer with wide, copper-
filled areas.
MOSFETs. The DL gate traces must be short and
wide (50 mils to 100 mils wide if the MOSFET is 1in
from the driver IC).
V
shown in the standard application circuit in Figure
2. This diagram can be viewed as having three sep-
arate ground planes: input/output ground, where all
the high-power components go; the power ground
plane, where the PGND pin, V
and driver IC ground connection go; and the con-
troller’s analog ground plane where sensitive ana-
log components, the master’s GND pin, and V
bypass capacitor go. The controller’s analog
ground plane (GND) must meet the power ground
plane (PGND) only at a single point directly
beneath the IC. The power ground plane should
connect to the high-power output ground with a
short, thick metal trace from PGND to the source of
the low-side MOSFETs (the middle of the star
ground).
tem ground planes) directly to the output-filter
capacitor positive and negative terminals with multi-
ple vias. Place the entire DC-DC converter circuit
as close to the CPU as is practical. Figure 13 is a
PCB layout example.
______________________________________________________________________________________
DD
OUT
bypass capacitor) together near the driver IC.
, and DL anode). If possible, make all these
Layout Procedure
DD
bypass capacitor,
CORE
and sys-
CC
IN
,
Figure 13. PCB Layout Example
FOR DCR SENSING
THE INDUCTORS
KELVIN SENSE
VIAS UNDER
EXPOSED PAD TO
CONNECT THE
ANALOG GND
C
C
IN
IN
INDUCTOR
C
C
OUT
OUT
V
CORE0
GROUND
POWER
V
INPUT
DDNB
V
CORE1
INDUCTOR
C
C
OUT
OUT
C
VCC
C
C
IN
IN
SPLIT CORE
CPU SOCKET
ANALOG
GROUND
(INNER
LAYER)