User`s guide

LONWORKS LPT-10 Transceiver User’s Guide 6-7
TVS devices used with LPT-10 transceivers must meet the following requirements:
• bi-directional protection;
• rated at 400W minimum peak power (10/1000µs waveform) rating;
• working peak reverse voltage rating V
rwm
≥ 42.4V (-40 to +85°C); V
rwm
should be
as low as possible over the temperature range but not less than 42.4V. Typical
reverse breakdown voltage ratings, V
br
, for such devices will be approximately 53V;
• bi-directional capacitance ≤ 275pF @Vr = 26V; bi-directional capacitance in this
application is typically 80% of data book unidirectional rating. Capacitance
increases as voltage across the device decreases.
Table 6.1 lists recommended TVS devices for use with LPT-10 transceivers.
Table 6.1 Recommended TVS Devices
Manufacturer Part Number Peak Power Package
Motorola SA45CA 500W Axial
General Instrument P4KE56CA 400W Axial
General Instrument BZW04-48B 400W Axial
General Instrument TGL41-56CA 400W SMT MELF
FCI Components P4KE-56CA 400W Axial
FCI Components L41-56CA 400W SMB
Vibration and Mechanical Shock Issues
The LPT-10 transceiver is designed to withstand moderate levels of vibration and
mechanical shock while operating. Echelon has tested the LPT-10 transceiver
operating in typical two-layer application boards to verify that the transceiver can
withstand occasional vibration levels up to 1.5g peak-to-peak over the frequency range
of 8Hz to 2kHz (where one "g" = 9.8m/s
2
), and occasional mechanical shocks up to 100g.
The main horizontal resonance of an LPT-10 transceiver that is soldered onto a multi-
layer PC board is approximately 300Hz, with a Q ≈ 10.
IEC 801 Testing
Echelon has tested the LPT-10 transceiver operating in typical two-layer application
boards to verify that the transceiver complies with the following IEC 801 test
requirements. As long as a node's PCB is designed following the guidelines in this user's
guide, the LPT-10 transceiver should pass the IEC 801 tests listed in table 6.2.