
A-6
Appendix A – Physical Layer Repeaters
5MHz
Clock
Oscillator
UA
UB
NET_A
NET_B
VCC
V+
GND
TXD
RXD
CLK
LPT-11
+5V
C1
L1
NET1
NET2
NET_A
NET_B
T1
FTT-10A
+5V
C1B
See text in FTT-10A
User Guide.
C4B
C3B
D2B
D1B
C5B
R1B
R2B
NET1
NET2
PCB
Spark Gaps
Q6
Q7
Q10
Q11
Q12
>CLK
RST
I0/CLK
I1
I2
I3
I4
I5
I6
I7
I8
I9
I10
I11
I/O9
RXDA
RXDB
RXDC
RXDD
I/O0
I/O6
I/O8
PAL 22V10-25
74HCT4020
Inputs from up to three
additional FTT-10A
transceivers (ground
any unused inputs)
{
+5V
2.2k,
5%
1/10W
Network
Segment A
Network
Segment B
INDUCTOR
C3
C2
RXDE
GND
T2
TXD
RXD
CLK
VCC
Add power supply bypass capacitors (not shown) next to oscillator, 74HCT4020 and PAL.
See Chapter 2 for LPT-11 transceiver component values L1 and C1, C2, C3.
C1B 0.1 µF
Note that a toroidal or shielded inductor should be used for L1 on all physical layer repeaters.
C4B 22µF, +50V polar (see
FTT-10A Free Topology Transceiver User's Guide).
C5B 0.1 µF, X7R or Y5V ceramic
PAL requires programming. See the
FTT-10A Free Topology Transceiver User's Guide.
Other components per table 2.3 in
FTT-10A Free Topology Transceiver User's Guide.
C3B 22µF, +50V polar (see
FTT-10A Free Topology Transceiver User's Guide).
R1B 1500
Ω
, 1%, 1/10W
R2B 576
Ω
, 1%, 1/10W
Figure A.5
N-Way Physical Layer Repeater Schematic
(-40°C to +85°C), For N = 2 to 5