EPE6169G Datasheet, PDF (2/2 Pages) PCA ELECTRONICS INC. – 10 Base-T PC Card Module with Enhanced CMA and Resistor Network

ELECTRONICS INC.
10 Base-T Interface Module with
Enhanced CMA and Resistor Network
EPE6169G
The circuit below is a guideline for interconnecting PCA’s EPE6169G with an ASIC requiring Sonic-T type resistors. 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.
A quick calculation of the effective Thevenin’s termination impedance for the filter follows:
R(termination)= 2(53.6//316)≈92. Thus, when measuring the return loss of these parts on the bench, it is necessary to
provide a shunting resistor of approximatively 7.5Ω representing the four 7.5Ω output signal sources.
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 EPE6169G. 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.
Typical Application Circuit for UTP PC Card
Card Bus
PHY
TX+
TXd+
TX-
TXd-
RX+
RX-
6
8
1 ^TX+
7
9 ^{2 TX-} _RJ45*
5
14 3 ^RX+
RX-
4
13 6
4 578
1
EPE6169G
3
12
10
PCA ELECTRONICS, INC.
16799 SCHOENBORN ST.
NORTH HILLS, CA 91343
Notes : * Pin-outs shown are for NIC configurations.
Chassis
Ground
CSE6169Gb Rev. 2 9/28/98
TEL: [phone]
FAX: [phone]
http://www.pca.com