
L
ON
W
ORKS
LPT-11 Transceiver User’s Guide
A-3
If the limits on the number of transceivers or total wire distance are exceeded, then a
link power physical layer repeater (figure A.2) can be added to interconnect two link
power network segments, or to connect a link power segment to other non-powered
FT segments.
Expansion
Link Power Network Segment
Link Power
Repeater
FTT-10A
Transceiver
LPT-11
Transceiver
Link Power Network Segment
Figure A.2
Two-Way Physical Layer Repeater Block Diagram
The LPT-11 transceiver is configured as a physical layer repeater by connecting it
“back-to-back” with one or more FTT-10A transceivers as shown in the following
figures. Only one LPT-11 transceiver may be used in a physical layer repeater – the
other transceiver(s) must be an FTT-10A transceiver.
Figure A.3 shows the schematic for a two-way physical layer repeater that operates
from 0
°
C to +85
°
C. Figure A.4 shows an N-way physical layer repeater that operates
from 0
°
C to +85
°
C, where N can be from three to four. Figure A.5 shows an N-way
physical layer repeater that operates from -40
°
C to +85
°
C, where N can be from two
to four. The LPT-11 SIP supplies the operating current for the FTT-10A
transceivers, the oscillator, and any other circuitry in the physical layer repeater.
Note that a toroidal or shielded inductor may be needed for the L1 inductor in the
LPT-11 DC-DC converter circuit in physical layer repeaters. Please see Appendix D
of the
FTT-10A Free Topology Transceiver User's Guide
for more information.
A packet that is received on any network segment is retransmitted on the other
segment(s). The physical layer repeater derives its operating power from the link
power network segment that is connected to the LPT-11 transceiver. See the
FTT-
10A Free Topology Transceiver User’s Guide
for more information about physical
layer repeaters built using the FTT-10A transceiver. Information about the JEDEC
programming file for the 22V10 PAL that is shown in figure A.5 can also be found in
the
FTT-10A Free Topology Transceiver User’s Guide
.
The maximum Idd that can be drawn from the LPT-11 SIP is 100mA, so the total of
the current consumption of the FTT-10A transceivers, plus the current consumption
of the oscillator and any other circuitry must be less than or equal to 100mA
maximum. This limits the total number of segments for an LPT-11 SIP-based
physical layer repeater to five or less, since each FTT-10A transceiver draws 20mA
maximum when in transmit mode. When the LPT-11 transceiver is receiving a