MAX15046_10 Datasheet, PDF(20/24 Page) Maxim Integrated Products – 40V, High-Performance, Synchronous Buck Controller

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40V, High-Performance, Synchronous

Buck Controller

PCB Layout Guidelines

Careful PCB layout is critical to achieve clean and stable

operation. The switching power stage requires particular

attention. Follow these guidelines for good PCB layout:

1) Place decoupling capacitors as close as possible to

the IC. Connect the power ground plane (connected

to PGND) and signal ground plane (connected to

GND) at one point near the device.

2) Connect input and output capacitors to the power

ground plane; connect all other capacitors to the sig-

nal ground plane.

3) Keep the high-current paths as short and wide as

possible. Keep the path of switching current (C2 to

IN and C2 to PGND) short. Avoid vias in the switching

paths.

4) Connect CSP to the drain of the low-side FET using a

Kelvin connection for accurate current-limit sensing.

5) Ensure all feedback connections are short and direct.

Place the feedback resistors as close as possible to the

IC.

6) Route high-speed switching nodes (BST, LX, DH, and

DL) away from sensitive analog areas (RT, FB, COMP,

and LIM).

24V Supply, 3.3V Output Operation

Typical Application Circuit 1 in the Typical Application

Circuits section shows an application circuit that oper-

ates out of 24V and outputs up to 10A at 3.3V. R5 sets

the switching frequency to 350kHz.

Single 4.5V to 5.5V Supply Operation

Typical Application Circuit 2 in the Typical Application

Circuits section shows an application circuit for a single

+4.5V to +5.5V power-supply operation.

Auxiliary 5V Supply Operation

Typical Application Circuit 3 in the Typical Application

Circuits section shows an application circuit for a +24V

supply to drive the external MOSFETs and an auxiliary

+5V supply to power the device

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