vsc8113 Vitesse Semiconductor Corp, vsc8113 Datasheet - Page 26

• Manufacturer Part Number: vsc8113
• Description: Atm/sonet/sdh 622 Mb/s Transceiver Mux/demux With Integrated Clock Generation And Clock Recovery
• Manufacturer: Vitesse Semiconductor Corp

ATM/SONET/SDH 622 Mb/s Transceiver Mux/Demux
with Integrated Clock Generation and Clock Recovery
Page 26
Layout of the High Speed Signals
include using controlled impedance lines and keeping the distance between components to an absolute mini-
mum. In addition, stubs should be kept at a minimum as well as any routing discontinuities. This will help min-
imize reflections and ringing on the high speed lines and insure the maximum eye opening. In addition the
output pull down resistor should be placed as close to the VSC8113 pin as possible while the AC-coupling
capacitor and the biasing resistors should be placed as close as possible to the optics input pin. The same is true
on the receive circuit side. Using small outline components and minimum pad sizes also helps in reducing dis-
continuities.
Ground Planes
tioned in an attempt to provide isolation to various components. Sectioning of the ground planes tends to inter-
fere with the ground return currents on the signal lines. In addition, the smaller the ground planes the less
effective they are in reducing ground bounce noise and the more difficult to decouple. Sectioning of the positive
supplies can provide some isolation benefits.
Table 19: AC Coupling Component Values
The routing of the High Speed signals should be done using good high speed design practices. This would
The ground plane for the components used in the High Speed interface should be continuous and not sec-
DRIVER
(Optics Module)
C1, C2, C3, C4
Component
GND
R1
R2
R3
R4
R1
741 Calle Plano, Camarillo, CA 93012 • 805/388-3700 • FAX: [phone]
PC Board Trace
VITESSE
Figure 13: AC Coupled High Speed I/O
VITESSE SEMICONDUCTOR CORPORATION
SEMICONDUCTOR CORPORATION
C1
Note: Only one side of a differential signal is shown.
+3.3V
GND
VSC8113
PECL I/O
.01uf High Frequency
270 ohms
190 ohms
75 ohms
68 ohms
Value
GND
R2
PC Board Trace
C2
+5.0V
GND
R3
R4
RECEIVER
(Optics Module)
Tolerance
VSC8113
Data Sheet
G52154-0, Rev 4.2
5%
5%
1%
1%
3/19/99