MAX8599 Maxim Integrated Products, MAX8599 Datasheet - Page 22

• Manufacturer Part Number: MAX8599
• Description: Low-Dropout Wide-Input-Voltage Step-Down Controllers
• Manufacturer: Maxim Integrated Products

Careful PC board layout is critical to achieve low
switching losses and clean, stable operation. The
switching power stage requires particular attention.
Follow these guidelines for good PC board layout:
1) Place the high-side MOSFET close to the low-side
2) Place the IC’s pin decoupling capacitors as close to
3) A current-limit setting resistor must be connected from
4) Try to keep the LX node connection to the IC pin
Low-Dropout, Wide-Input-Voltage,
Step-Down Controllers
22
TOP VIEW
MOSFET and arrange them in such a way that the
drain of the high-side MOSFET and the source of
the low-side MOSFET can be tightly decoupled with
a 10µF or larger ceramic capacitor. The MOSFETs
should also be placed close to the controller IC,
preferably not more than 1.5in away from the IC.
pins as possible.
ILIM directly to the drain of the high-side MOSFET.
separate from the connection to the flying boost
capacitor.
______________________________________________________________________________________
Pin Configurations (continued)
FREQ
ILIM
POK
LX
13
14
15
16
Applications Information
12
1
4mm x 4mm
THIN QFN
MAX8598
MAX5899
11
2
PC Board Layout Guide
10
3
4
9
8
7
6
5
VL
V+
EN
COMP
5) Keep the power ground plane (connected to the
6) Place the RC snubber circuit as close to the low-
7) Keep the high-current paths as short as possible.
8) Connect the drains of the MOSFETs to a large cop-
9) Ensure the feedback connection is short and direct.
10) Route high-speed switching nodes, such as LX,
TRANSISTOR COUNT: 4493
PROCESS: BiCMOS
source of the low-side MOSFET, PGND pin, input
and output capacitors’ ground, VL decoupling
ground) and the signal ground plane (connected to
GND pin and the rest of the circuit ground returns)
separate. Connect the two ground planes together
at the ground of the output capacitor(s).
side MOSFET as possible.
per area to help cool the devices and further
improve efficiency and long-term reliability.
Place the feedback resistors as close to the IC as
possible.
DH, and DL away from sensitive analog areas (FB,
COMP, ILIM, AIN+, AIN-).
Refer to the MAX8597/MAX8598/MAX8599 evalua-
tion kit for a sample board layout.
Chip Information
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