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

L (µH) C (nF)

110

15

150

10

10

0

13

6.8

0

150

6.8

0

N

1 µF

C3

R1

5 V

C2

330 µH

L1

R3

2

Ω

F ilter

Gain =

− R2 / R1

R2

L2

L

24 k

Ω

HCPL - 8100/0810

1

2

3

4

5

6

7

8

Status

Tx-en

Tx-in

R ref

GND

GND

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-

connected from pin 4 to ground. The optimum biasing

point value for modulation frequencies up to 150 kHz

is 4 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 C and inductor L1 attenuate the 50/60 Hz

powerline transmission frequency. A suitable value for

L1 can range in value from 00 µH to 1 mH. To reduce the

series coupling impedance at the modulation frequency,

L is included to compensate the reactive impedance of

C. This inductor should be a low resistive type capable

of meeting the peak current requirements. To meet many

regulatory requirements, capacitor C needs to be an X

type. Since these types of capacitors typically have a very

wide tolerance range of 0%, it is recommended to use as

low Q factor as possible for the L/C combination. Using

a high Q coupling circuit will result in a wide tolerance on

the overall coupling impedance, causing potential commu-

nication difficulties with low powerline impedances. Occa-

sionally with other circuit configurations, a high Q coupling

arrangement is recommended, e.g., C less than 100 nF. In

this case it is normally used as a compromise to filter out

of band harmonics originating from the line driver. This is

not required with the HCPL-8100 or HCPL-0810.