USER MANUAL
TCM 410J
–
Transceiver Module
© 2022 EnOcean | www.enocean.com
TCM 410J User Manual | v2.3 | June 2022 | Page 34 / 46
4.3
Power supply requirements
In order to provide a good radio performance, great attention must be paid to the power
supply and a correct layout and shielding. It is recommended to place a 22 µF ceramic ca-
pacitor between VDD and GND close to the module (material: X5R, X7R, min 6.3 V to avoid
derating effects).
In addition, an HF SMD EMI Suppression Ferrite Bead such as the Würth WE-CBF HF SMD
EMI Suppression Ferrite Bead (Würth order number 742863160) shall be inserted in the
power supply line.
For best performance it is recommended to keep the ripple on the power supply rail below
10 mVpp (see 2.4).
All GND pins must be connected to GND. Be careful not to create loops! The
ground must be realized ideally on both sides of the PCB board with many Vias.
At least there must be a short star connection. Otherwise, RF performance can
be reduced!
4.4
Layout recommendations
The length of lines connected to I/Os should not exceed 5 cm.
It is recommended to have a complete GND layer in the application PCB, at least
in the area below the module and directly connected components (e.g. mid-layer
of your application PCB).
Due to unisolated test points there are live signals accessible on the bottom side
of the module.
Please follow the following guidance to minimize interference with your applica-
tion circuit:
◼
We suggest avoiding any copper structure in the area directly underneath
the module (top-layer layout of your application PCB). If this is not possi-
ble in your design, please provide coating on top of your PCB to prevent
short circuits to the module. All bare metal surfaces including vias have to
be covered (e.g. adequate layout of solder resist).
◼
It is mandatory that the area marked by the circle in the figure below is
kept clear of any conductive structures in the top layer and 0.3 mm be-
low. Otherwise, RF performance will be degraded!
Furthermore, any distortive signals (e.g. bus signals or power lines) should not
be routed underneath the module. If such signals are present in your design, we
suggest separating them by using a ground plane between module and these sig-
nal lines.
