MAX1711 Maxim, MAX1711 Datasheet - Page 26

• Manufacturer Part Number: MAX1711
• Description: High-Speed / Digitally Adjusted Step-Down Controllers for Notebook CPUs
• Manufacturer: Maxim

High-Speed, Digitally Adjusted
Step-Down Controllers for Notebook CPUs
26
1) Place the power components first, with ground termi-
2) Mount the controller IC adjacent to MOSFET Q2,
3) Group the gate-drive components (BST diode and
4) Make the DC-DC controller ground connections as
nals adjacent (Q2 source, CIN-, COUT-, D1 anode). If
possible, make all these connections on the top layer
with wide, copper-filled areas.
preferably on the back side opposite Q2 in order to
keep LX-PGND current-sense lines and the DL gate-
drive line short and wide. The DL gate trace must be
short and wide, measuring 10 to 20 squares (50 to
100 mils wide if the MOSFET is 1 inch from the con-
troller IC).
capacitor, V
controller IC.
shown in Figure 11. This diagram can be viewed as
having three separate ground planes: output ground,
TOP VIEW
______________________________________________________________________________________
PGOOD
SHDN
GNDS
DD
GND
ILIM
TON
FBS
V
REF
CC
V+
FB
CC
bypass capacitor) together near the
10
11
12
1
2
3
4
5
6
7
8
9
MAX1710
QSOP
Layout Procedure
24
23
22
21
20
19
18
17
16
15
14
13
DH
LX
BST
SKIP
D0
D1
D2
D3
OVP
V
PGND
DL
DD
5) Connect the output power planes (V
where all the high-power components go; the PGND
plane, where the PGND pin and V
tor go; and an analog GND plane, where sensitive
analog components go. The analog ground plane
and PGND plane must meet only at a single point
directly beneath the IC. These two planes are then
connected to the high-power output ground with a
short connection from V
of the low-side MOSFET, Q2 (the middle of the star
ground). This point must also be very close to the out-
put capacitor ground terminal.
ground planes) directly to the output filter capacitor
positive and negative terminals with multiple vias.
Place the entire DC-DC converter circuit as close to
the CPU as is practical.
TOP VIEW
PGOOD
SHDN
GNDS
GND
ILIM
TON
FBS
V
REF
CC
V+
FB
CC
10
11
12
1
2
3
4
5
6
7
8
9
MAX1711
Pin Configurations
QSOP
DD
cap/PGND to the source
DD
24
23
22
21
20
19
18
17
16
15
14
13
CORE
DH
LX
BST
SKIP
D0
D1
D2
D3
D4
V
PGND
DL
bypass capaci-
DD
and system