EPE6338S [PCA]
Miniature 10 Base-T Isolation Transformer with Center Taps; 微型10 BASE-T隔离变压器与中心抽头
| 型号： | EPE6338S |
| 厂家： | 
PCA ELECTRONICS INC. |
| 描述： | Miniature 10 Base-T Isolation Transformer with Center Taps |
| 文件： | 总2页 (文件大小：26K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Miniature 10 Base-T Isolation
Transformer with Center Taps
E L E C T R O N I C S I N C .
EPE6338S
• Optimized for Level One LXT905 •
• Robust design allows for toughest soldering processes •
• Small outline package on 0.050” pitch 16 pin SOIC •
• Complies with or exceeds IEEE 802.3, 10 Base-T Requirements •
• Operating temperature : -40°C to +85°C •
Electrical Parameters @ 25° C
Cable Side
Inductance
(µH Min.)
Interwinding
Capacitance
(pF Max.)
Leakage
Inductance
(µH Max.)
Return Loss
(dB Min.)
Hipot
(Vrms)
Transceiver Side
DCR
(Ω Max.)
@ 100 KHz,
0.1 Vrms
@ 100 KHz,
0.1 Vrms
@ 100 KHz,
0.1 Vrms
5-10
MHz
Rcv
Rcv
200
Xmit
200
Xmit
0.35
0.50
12
0.3
-20
1500
Schematic
Transmit
1:2
Receive
1:1
6
11
16
1
Transceiver
Side
Cable
10
Transceiver
Cable
Side
2
3
15
14
7
8
Side
Side
9
Package
A
Dimensions
N
(J)
P
(Inches)
(millimeters)
Dim. Min.
Max. Nom.
Min. Max. Nom.
PCA
EPE6338S
Date Code
Suggested
A
B
C
D
E
F
G
H
I
(J)
K
L
M
N
P
Q
.480
.260
.180
.350
.005
.050
.370
.016
.010
.070
0°
.500
.280
.200
Typ.
.015
Typ.
.390
.022
Typ.
Typ.
8°
.045
.030
.050
.055
.410
12.19 12.70
Solder
B
6.60
4.57
8.89
.127
1.27
9.40
.406
.254
1.78
0°
7.11
5.08
Typ.
.381
Typ.
9.91
.559
Typ.
Typ.
8°
Q
Pad Layout
M
D
.025
.635
1.14
C
E
.762
1.27
K
I
1.40
10.41
F
H
L
G
CSE6338Sa Rev. - 9/1/98
PCA ELECTRONICS, INC
16799 SCHOENBORN ST.
NORTH HILLS, CA 91343
TEL: (818) 892-0761
FAX: (818) 894-5791
http://www.pcainc.com
Product performance is limited to specified parameters. Data is subject to change without prior notice.
Miniature10 Base-T Isolation
Transformer with Center Taps
E L E C T R O N I C S I N C .
EPE6338S
The circuit below is a guideline for interconnecting PCA’s EPE6338S with LXT905 10 Base-T PHY chip over UTP cable.
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 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. Additionally, the following need to be
considered while selecting resistor values :
a. Each channel needs 100Ω termination, thus the Thevenin’s equivalent resistance seen by a channel looking into the
transmit outputs from the chip must be equal to a value close to 100Ω. The LXT 905 driver output impedances are very low. .
Thus only 11.8Ω on TPON & TPOP are enough to provide a balanced 25 Ω termination given that turns ratio is 1:2. Following
these guidelines will guarantee that the return loss specifications are satisfied at all extremes of cable impedance (i.e. 85Ω to
115Ω) while the module is installed in your system. The receiver channel termination is rather straight forward: two 50Ω loads
provide the balanced termination to the cable.
b. That the template requirements are satisfied under the worst case Vcc (i.e. 4.5V), will impose a further constraint on
resistor selection, in that they ought to be the minimum derived from the calculations. Users can allow for pads on their PCB
for a shunting resistor across pins 6 and 8 of EPE6338S for more flexibility in setting voltage levels at the outputs.
Note that some systems have auto polarity detection and some do not. If not, be certain to follow the proper polarity.
The pulldown resistors used 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 EPE6338S. There need not be any ground plane beyond this
point.
For best results, PCB designer should design the outgoing traces preferably to be 50Ω, balanced and well coupled to achieve
minimum radiation from these traces.
Typical Application Circuit for UTP with external Resistor Network
TPIN
1
2
TX+
TX-
9
1
2
3
6
11
14
16
15
RJ45*
RX+
RX-
EPE6338S
LXT905
PHY
7
4
5
8
3
TPIP
8
6
10
11.8Ω
11.8Ω
TPON
HV Cap
TPOP
High voltage cap, if used
2KV recommended
.1uF
X7R
Chassis
Ground
Notes : * Pin-outs shown are for NIC configurations.
For Hubs and Repeaters swap pins 1-2 with pins 3-6.
CSE6338Sb Rev. - 9/1/98
PCA ELECTRONICS, INC.
16799 SCHOENBORN ST.
NORTH HILLS, CA 91343
TEL: (818) 892-0761
FAX: (818) 894-5791
http://www.pcainc.com
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