1
MHz
5
MHz
20
MHz
70
MHz
100
MHz
200
MHz
Insertion Loss
Common Mode Rejection
(dB Min.)
Return Loss
(dB Min.)
1-4
MHz
100
KHz
-65
1-6
MHz
6-17
MHz
17-25
MHz
-.5
100
-.8
-1
-1.9
-7
-25
Electrical Parameters @ 25 C
Token Ring Interface Module
Optimized for Texas Instrument's TI38054
Supports both UTP Transmission
Complies with or exceeds IEEE 802.5 Requirements
Dimensions
A
B
C
D
E
F
G
H
I
J
K
Dim.
.990
.442
.351
---
.005
---
.525
.016
---
---
.125
Min.
1.000
.462
.371
---
.025
---
.555
.022
---
---
.150
Max.
.995
.452
.361
.700
.015
.100
.540
.020
.010
.147
.138
Nom.
(Inches)
(Millimeters)
25.15
11.23
8.92
---
.130
---
13.34
.406
---
---
3.18
Min.
25.65
11.73
9.42
--
.640
---
14.10
.559
---
---
3.81
Max.
25.27
11.48
9.17
17.78
.381
2.54
13.72
.508
2.54
3.75
3.50
Nom.
Package
EPT7088
Impedance
(
)
Cable Side
-30
-25
E L E C T R O N I C S I N C .
600
Chip Side
8
MHz
16
MHz
24
MHz
32
MHz
36
MHz
44
MHz
80
MHz
-14
( dB Max. )
( dB Min. )
-12
-8
-45
-30
-30
-15
-15
-20
White dot
pin #1
PCA
EPT7088
Date Code
B
A
J
D
K
C
F
H
E
G
I
Schematic
Pins 4 , 5 , 12 , 13 are Not Connected
Xmit
Filter
CMF
9 Tu+
8 Tu-
3 , 14
10
7
Impedance
Matching
Network
Tx+ 16
Tx- 1
Ph- 6
Ph+ 11
15
2
CST7088 Rev. 1 1/19/99
TEL: (818) 892-0761
FAX: (818) 894-5791
http://www.pca.com
PCA ELECTRONICS, INC.
16799 SCHOENBORN ST.
NORTH HILLS, CA 91343
Product performance is limited to specified parameters. Data is subject to change without prior notice.
Token Ring Transceiver Module
Typical Application Circuit Connection to TMS38054 (or Equivalent)
E L E C T R O N I C S I N C .
EPT7088
The circuit below is a guideline for interconnecting PCA's EPT7088 with a typical Token Ring PHY chip for 4 Mb/16Mb
applications over UTP cable. Further details of system design should be obtained from the specific chip manufacturer.
Note that this module is optimized for a "current source" driver such as TMS38054.
Typical insertion loss of the isolation transformer is 0.5dB up to 16 MHz. The Toek Ring filter design follows the I.E.E.E
802.5 last recommendations in the Standard regarding the differential phase delay and the return loss right up to the filter
cut off frequency. This module requires either a receiver module with only isolation transformer/common mode choke
combination(such as the EPT7089) or another module identical to the EPT7088 to complete the transceiver operation.
The pull down resistors to chassis via a cap shown around the RJ45 connector have been known to suppress unwanted
radiation that unused wires pick up from the immediate environment. This is specially true if driving UTP cable. Their
placement and use are to be considered carefully before a design is finalized.
No specific recommendation is made here for phantom circuitry, implementation varies. Please note that additional
emission control has been observed if both nodes of the phantom bypass capacitor on the transmit channel are pulled to
the chassis ground via suitable capacitors.
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 EPT7088. There need not be any ground plane beyond
this point.
For best results, PCB designer should design the outgoing traces preferably to be 50
, balanced and well coupled to
achieve minimum radiation from these traces.
Notes : Phantom returns are left unconnected. Applications vary. Your system may have a phantom drive return
detection circuit needing pins 7 & 6 to be connected separately. Receiver CT can be grounded via a cap.
CST7088 Rev. 1 1/19/99
TEL: (818) 892-0761
FAX: (818) 894-5791
http://www.pca.com
PCA ELECTRONICS, INC.
16799 SCHOENBORN ST.
NORTH HILLS, CA 91343
TMS38054
RJ45
4
5
3
6
RCVINA 38
PHOUTA 29
50
/2W
50
/2W
EPT7088
100
6
15
9
8
30
0
30
0
+5V
RCVINB 37
PHOUTB 27
DROUTA 32
DROUTB 31
11
2
16
1
5v
+5V
+5V
10F
10F
Use only
one connector
8
7
1
2
3
14
8
5
7
6
PH RET A
PH RET B
CT
1
4
2
EPT7089
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