Si446x 无线模块PCB设计指导

Rev. 0.3 Copyright © 2014 by Silicon Laboratories AN629

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Si4460/61/63/64/67/68 RF ICs Layout Design Guide

1. Introduction

The purpose of this application note is to help users design PCBs for the next generation EZRadioPRO™ RF ICs,

i.e. the Si4460/61/63/64/67/68 devices (henceforth referred to as EZRadioPRO™ RF ICs) using good design

The compact RF part of the designs is highlighted by a silkscreen frame, and it is strongly recommended to

Figure 1. Compact RF Part of the Designs Highlighted on Top Silkscreen

When layouts cannot be followed as shown by the reference designs (due to PCB size and shape

2 Rev. 0.3

Switched TX/RX

Diversity

In the Split TX/RX type, the TX and RX paths are separated, and individual SMA connectors are provided for each

In the Diversity type, there are two antennas, both of which can be connected either to the TX or the RX path by a

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depending on the harmonic restrictions of the relevant EMC regulation. The layout issues of the SQW type

matching will be discussed in this section as well. This type of matching can be used effectively when the required

subject.

Some general rules of thumb for designing RF-related layouts for good RF performance are:

Use as much continuous ground plane metalization as possible.

Avoid the separation of the ground plane metalization.

Use as many grounding vias (especially near to the GND pins) as possible to minimize series parasitic

inductance between the ground pour and the GND pins.

Use a series of GND vias (a so called “via curtain”) along the PCB edges and internal GND metal pouring

Try to avoid placing the nearby inductors in the same orientation to reduce the coupling between them.

Avoid using loops and long wires to obviate its resonances.

Always ensure good V

4 Rev. 0.3

In this section, a four-layer design (based on the layout of the 4463-PCE20B915 (4463CPCE20B915) Pico Boards)

and a two-layer design (based on the layout of the 4438-PCE20B490 (4438CPCE20B490) Pico Boards) are

shown.

The layout design recommendations for the TX only and RX only Pico Boards are also fully covered in this section

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the internal drain pin.

The TX and RX sections should be separated as much as possible on the top layer to reduce coupling. If

The neighboring matching network components should be placed as close to each other as possible in

Improve the grounding effect in the thermal straps used with capacitors. In addition, thicken the trace near

bottom layer GND plane) will further help reduce these effects.