User`s guide

LONWORKS FTT-10A Transceiver User’s Guide B-3
FTT-10A PCB Layout
Item Check When
Completed
Description
13 Star ground configuration used.
14 Keepout areas observed for PCB.
15 D1/D2 clamp diodes in place with the correct value.
16 Ground planes or wide traces used to lower inductance of the
ground system.
17 Vcc routed to the transceiver via a narrow trace ≤0.3mm
(0.012") width.
18 C1 placed immediately next to the transceiver.
19 Transceiver ground pin connected to center of star ground via
wide and short trace.
20 The “leakage” capacitance from high frequency circuit traces
is controlled via guard traces.
21 The product's package is designed to minimize the possibility
of ESD hits arcing into the node's circuit board. If the
product's package is plastic, then the PCB is supported in
the package so that unprotected circuitry on the PCB is not
adjacent to any seams in the package. The PCB is not
touching the plastic enclosure near a seam.
22 Explicit clamping of user-accessible circuitry is used to shunt
ESD currents from that circuitry to the center of the star
ground on the PCB.
23 The connector, diodes and decoupling capacitor are all
located close to the center of the star ground.
FTT-10A Transceiver Programming
Item Check When
Completed
Description
24 The correct standard transceiver type is defined for the
transceiver.
FTT-10A Transceiver Power Supply - General
Item Check When
Completed
Description
25 Supply provides 4.75VDC minimum, 5.25VDC maximum.