EPT7061GM Datasheet, PDF (2/2 Pages) PCA ELECTRONICS INC. – Miniature Token Ring Transceiver Module

ELECTRONICS INC.
Miniature Token Ring Transceiver Module
EPT7061GM
The circuit below is a guideline for interconnecting PCA’s EPT7061GM with a typical Token Ring PHY chip for 4 Mb/16Mb
applications over STP or UTP cable. Further details of system design should be obtained from the specific chip
manufacturer. Note that this module is optimized for a “voltage source” driver such as TI380C60. Only one type of cable
should be driven by the module: either UTP or STP.
Note that the two channels have identical filtering and other magnetics . This option is seen to be widely used by system
designers when designing dedicated Token Ring systems.
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 return 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 EPT7061GM. There need not be any ground plane beyond
this point.
For best results, PCB designer should design the outgoing traces preferably to be 50Ω (UTP), balanced and well coupled to
achieve minimum radiation from these traces.
Typical Application Circuit Connection to TI380C60 (or Equivalent). Only NIC side shown.
Rcv-
Rcv+
PHOUTA
PHOUTB
DTR PHY
Xmit+
Xmit-
2
7
1
8
PH-B
+5V
3
9
PH-A
4
10
+5V
50Ω/2W
14
50Ω/2W
10µF
10µF
13
100Ω
100Ω
15 _EPT7061GM
16
4 _Rcv±
5
RJ45
3 _Xmit±
6
127 8
Notes : 1. Pins 3 & 4 are left unconnected. Applications vary. Your system may have a phantom drive return
detection circuit needing pins 3 & 4 to be connected separately.
PCA ELECTRONICS, INC.
16799 SCHOENBORN ST.
NORTH HILLS, CA 91343
CST7061GMb Rev. 2 2/27/98
TEL: [phone]
FAX: [phone]
http://www.pca.com