The circuit below is a guideline for interconnecting PCA’s EPA2116G with AMD 79C96X and -970, PCnet chip family as

reference controllers. Further details of system design, such as chip pin-out, etc. can be obtained from the specific chip

manufacturer.

Typical insertion loss of the isolation transformer/filter is 0.7dB. This parameter covers the entire spectrum of the encoded

signals in 10 Base-T protocols. However, the predistortion resistor network introduces some loss which has to be taken

into account in determining how well your design meets the Standard Template requirements.

Users are encouraged to verify if this network best suits their application needs with the chip manufacturer before choosing

a specific set of values. Additionally, user should make sure that these resistor values provide 802.3 Return Loss

specification complaince at either extremes of the cable impedance, namely; 85

Ω to 115Ω. Implement only those parts in

the design that will meet this requirement.

A quick calculation of the effective Thevenin’s termination impedance for the filter follows:

R(termination)= 2(61.9//422)//1.2K

≈100Ω.

Thus, when measuring the return loss of these parts on the bench, it is not necessary to provide a shunting resistor across

the four outputs.

The phantom resistors shown around the RJ45 connector have been known to suppress unwanted radiation that unused

wires pick up from the immediate environment. Their placement and use are to be considered carefully before a design is

finalized.

It is recommended that there be a neat separation of ground planes in the layout. It is generally accepted practice to limit

the plane off at least 0.08 inches away from the chip side pins of EPA2116G. There need not be any ground plane beyond

this point.

For best results, PCB designer should design the outgoing traces preferably to be 50

Ω, balanced and well coupled to

achieve minimum radiation from these traces.

CSA2116Gb

Rev. A

2/18/98

10Base-T Module with

Enhanced Common Mode Attenuation

Typical Application Circuit for UTP

E L E C T R O N I C S I N C .

Notes : * Pin-outs shown are for NIC configurations.

For Hubs and Repeaters swap pins 1-2 with pins 3-6.

EPA2116G

10 Base-T

PHY

RJ45*

1

2

6

3

TX+

TXd+

RX+

RX-

EPA2116G

TX+

TX-

RX+

RX-

TX-

TXd-

Chassis

Ground

8

7

45

8

6

9

11

1

2

4

3

14

16

12

5

TEL: (818) 892-0761

FAX: (818) 894-5791

http://www.pca.com

PCA ELECTRONICS, INC.

16799 SCHOENBORN ST.

NORTH HILLS, CA 91343