100BX Module for
Multi-port Application with
Enhanced Common Mode Attenuation
ELECTRONICS INC.
EPF8032S
• Optimized for DP83840A/Twister combination •
• Recommended for use with ICS1890 series, SSI TSC78Q2120 chips •
(with appropriate circuitry)
• Guaranteed to operate with 8 mA DC bias at 70°C •
• Complies with or exceeds IEEE 802.3, 10 BT/100 BX Standards •
Electrical Parameters @ 25° C
Insertion Loss
(dB Max.)
OCL
@ 70°C
100 KHz, 0.1 Vrms
8 mA DC Bias
Cable Side
0.1-80
MHz
Return Loss
(dB Min.)
100
MHz
150
MHz
1-10
MHz
Common Mode Rejection
(dB Min.)
60
MHz
100
MHz
30-100
MHz
200-300
MHz
Crosstalk (dB Min.)
[Between Channels]
500
MHz
5-10
MHz
10-100
MHz
-40
-30
Xmit Rcv Xmit Rcv Xmit Rcv Xmit Rcv Xmit Rcv Xmit Rcv Xmit Rcv Xmit Rcv Xmit Rcv
350µH
-1
-1
-1
•
-1
-3.5
-3
-18
Isolation : 1500 Vrms •
-18
-18
-18
-10
-10
-35
-30
-20
-20
Impedance : 100 Ω • Rise Time : 3.0 nS Max.
-15
-15
•
Schematic
Transmit Channel
1(12)
Receive Channel
34(23)
7(18)
1:1
100BX
40(29)
2(13)
8(19)
33(22)
1:1
3(14)
32(21)
9(20)
39(28)
4(15)
38(27)
10BT
0.5 : 1
5(16)
Dimensions
Package
A
N
J
PCA
EPF8032S
Date Code
B
Q
40
21
P
Solder Pad Layout
1
20
D
M
I
K
C
F
H
E
Dim.
Min.
A
B
C
D
E
F
G
H
I
J
K
L
M
N
P
Q
1.110
.470
.235
.950
.008
.050
.620
.016
.008
.085
0°
.045
(Inches)
Max. Nom.
1.130
.490
.255
Typ.
.012
Typ.
.640
.022.
.012
Typ.
8°
Typ.
(Millimeters)
Min. Max. Nom.
28.19
11.94
5.97
24.13
.203
1.27
15.75
.406
.203
2.16
0°
1.14
.030
.050
.090
.670
28.70
12.45
6.48
Typ.
.305
Typ.
16.26
.559
.305
Typ.
8°
Typ.
.762
1.27
2.29
17.02
L
G
PCA ELECTRONICS, INC.
16799 SCHOENBORN ST.
NORTH HILLS, CA 91343
CSF8032Sa Rev. 2 5/16/97
TEL: (818) 892-0761
FAX: (818) 894-5791
http://www.pca.com
100BX Module for
Multi-port Application with
Enhanced Common Mode Attenuation
ELECTRONICS INC.
The circuit below is a guideline for interconnecting PCA’s EPF8032S with National DP83840A and DP83223 twister chip set
for 10/100 Mb/s applications. Further details can be obtained from the chip manufacturer application notes. Please
consult PCA for applications help regarding the SSI78Q2120 or ICS1890 series parts or consult with the respective
application notes.
Typical insertion loss of the isolation transformer is 0.5dB. This parameter covers the entire spectrum of the encoded
signals in 10/100 protocols. Under terminated conditions, to transmit a 2V pk-pk signal across the cable, you must adjust
the TXREF resistor of the twister chip to get at least 2.12V pk-pk across pins 16-15.
Note that significant low frequency response improvement can be obtained in the system (improving equalization effects) if
the DC blocking capacitors were not used; this can only be done by choosing a different pinout for the 10 Base-T receiver
side. This is accomplished without impacting any other behavior. If any user has a need to improve this feature, please
consult with the PCA Technical support group. Parts similar to EPF8032S are available from several LAN magnetics
vendors.
It is recommended that system designers do not ground the receiver side center tap, via a capacitor. This may worsen
EMI, specifically if the secondary “common mode termination” is pulled to chassis ground as shown.
The phantom resistors shown around the 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.
The “common mode termination” load of 75 Ω shown from the center taps of the secondary may be taken to chassis ground
via a cap of suitable value. This depends upon user’s design, EMI margin etc.
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 0.05 inches away from the chip side pins of EPF8032S. 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 (only one port shown)
0.10µF {Note 1}
+
7
-
8
0.1µF
{Note 1}
1000pF
8
34
RXD
Rcv
50Ω
33
75Ω
32
12.1Ω
4
+
TXU
12.1Ω
5
-
1
1000pF
-
RXI
12.1Ω
PMRD
12.1Ω
TXO
+
TD
-
4
40
Xmit
RJ45*
1
39
75Ω
2
38
2000V
2
+
50Ω
7
1
5
EPF8032S
6
Isolation Cap
3
Chassis
Ground
DP83223
DP83840A
SD
PMID
+
SD
+
RD
-
PCA ELECTRONICS, INC.
16799 SCHOENBORN ST.
NORTH HILLS, CA 91343
Other pull down/up resistors not shown, for clarification please refer to National’s application notes.
Notes : 1. See text above for clarification.
2. Hub side connections show only one port.
CSF8032Sb Rev. 2 5/16/97
TEL: (818) 892-0761
FAX: (818) 894-5791
http://www.pca.com