MICRF600 datasheet(18/19 Pages) MICREL

18 / 19 page

Micrel, Inc.

MICRF600

September 2005

M9999-091905

Layout

Recommended Land Pattern

Figure 12 shows a recommended land pattern that

facilitates both automatic and hand assembling.

Figure 13. Recommended Land Pattern

Layout Considerations

Except for the antenna input/output signal, only digital and

low frequency signals need to interface with the module.

There is therefore no need of years of RF expertise to do a

successful layout, as long as the following few points are

being followed:

•

Proper ground is needed. If the PCB is 2-layer, the

bottom layer should be kept only for ground. Avoid

signal traces that split the ground plane. For a 4-

layer PCB, it is recommended the second layer

only for ground be kept.

•

A ground via should be placed close to all the

ground pins. The bottom ground pad should be

penetrated with 4-16 ground vias.

•

The antenna has a impedance of ~50Ω. The

antenna trace should be kept to 50Ω to avoid

signal reflection and loss of performance. Any

transmission line calculator can be used to find the

needed trace width given a board build up.

Example: A trace width of 44 mil (1.12 mm) gives

50 impedance on a FR4 board (dielectric

cons=4.4) with copper thickness of 35

µm and

height (layer 1-layer 2 spacing) of 0.61 mm.

MICRF600 데이터시트(PDF) 18 Page - Micrel Semiconductor