Application Information
The HCPL-8100 and HCPL-0810 are designed to work with
various transceivers and can be used with a variety of
modulation methods including ASK, FSK and BPSK. Figure
17 shows a typical application in a powerline modem using
Frequency Shift Keying (FSK) modulation scheme.
Figure 17. Schematic of HCPL-8100 or HCPL-0810 application for FSK modulation scheme.
Table 1. Typical component values
for LC coupling network.
Figure 18. LC coupling network.
GND
Tx
X2
C2
N
L2
L1
L
1 µF
C3
Carrier
Frequency (kHz)
LC Coupling
L2 (µH) C2 (nF)
110 15 150
120 10 220
132 6.8 220
150 6.8 220
N
1 µF
C3
R1
5 V
C2
330 µH
L1
R3
2
Ω
F ilter
Gain =
−
R2 / R1
R2
L2
L
R
ref
24 k
Ω
HCPL - 8100/0810
1
2
3
4
5
6
7
8
Status
Tx-en
Tx-in
R
ref
GND
GND
V
CC
Tx -out
PLM
Transceiver
STATUS
TX-EN
TX
D1
C4
100 nF
100 nF
C1
C5
100 µF
X2
Line Driver
The line driver is capable of driving powerline load imped-
ances with output signals up to 4 V
PP
. The internal biasing
of the line driver is controlled externally via a resistor R
ref
connected from pin 4 to ground. The optimum biasing
point value for modulation frequencies up to 150 kHz
is 24 kW. For higher frequency operation with certain
modulation schemes, it may be necessary to reduce the
resistor value to enable compliance with international
regulations.
The output of the line driver is coupled onto the powerline
using a simple LC coupling circuit as shown in Figure
18. Refer to Table 1 for some typical component values.
Capacitor C2 and inductor L1 attenuate the 50/60 Hz
powerline transmission frequency. A suitable value for
L1 can range in value from 200 µH to 1 mH. To reduce the
series coupling impedance at the modulation frequency,
L2 is included to compensate the reactive impedance of
C2. This inductor should be a low resistive type capable
of meeting the peak current requirements. To meet many
regulatory requirements, capacitor C2 needs to be an X2
type. Since these types of capacitors typically have a very
wide tolerance range of 20%, it is recommended to use as
low Q factor as possible for the L2/C2 combination. Using
a high Q coupling circuit will result in a wide tolerance on
the overall coupling impedance, causing potential commu-
nication diculties with low powerline impedances. Occa-
sionally with other circuit congurations, a high Q coupling
arrangement is recommended, e.g., C2 less than 100 nF. In
this case it is normally used as a compromise to lter out
of band harmonics originating from the line driver. This is
not required with the HCPL-8100 or HCPL-0810.
