MICRF230 datasheet(15/20 Pages) MICREL

15 / 20 page

Micrel, Inc.

MICRF230

PCB Considerations and Layout

The MICRF230 evaluation board is a good starting point

for prototyping of most applications. The Gerber files are

downloadable from the Micrel website and contain the

remaining layers needed to fabricate this board. When

copying or making one’s own boards, make the traces as

short as possible. Long traces alter the may become

invalid. Suggested matching values may vary due to PCB

variations. A PCB trace 100 mils (2.5mm) long has about

1.1nH inductance. Optimization should always be done

with range tests. Make sure the individual ground

connection has a dedicated via rather than sharing a few

of ground points by a single via. Sharing ground via will

increase the ground path inductance. Ground plane should

be solid and with no sudden interruptions. Avoid using the

ground plane on the top layer next to the matching

elements. It normally adds additional stray capacitance

which changes the matching. Do not use Phenolic

materials as they are conductive above 200MHz. FR4 or

better materials are recommended. The RF path should be

as straight as possible to avoid loops and unnecessary

turns. Separate ground and VDD lines from other digital or

switching power circuits (such as microcontrollers, etc.).

Known sources of noise should be laid out as far as

possible from the RF circuits. Avoid unnecessary wide

traces which would add more distribution capacitance

(between top trace to bottom GND plane) and alter the RF

parameters.

April 15, 2015

Revision 2.0

MICRF230 Datasheet(PDF) 15 Page - Micrel Semiconductor