V23870-A1317-K500 Infineon Technologies, V23870-A1317-K500 Datasheet - Page 13

• Manufacturer Part Number: V23870-A1317-K500
• Manufacturer: Infineon Technologies

Specifications of V23870-A1317-K500

• Number Of Receivers: 1
• Operating Supply Voltage (typ): 3.3V
• Operating Temperature Classification: Commercial
• Operating Supply Voltage (max): 3.6V
• Pin Count: 20
• Operating Temperature (max): 70C
• Operating Temperature (min): 0C
• Supply Current: 135mA
• Lead Free Status / RoHS Status: Supplier Unconfirmed

V23870-A131x-K500
Application Notes
Application Notes
EMI-Recommendations
To avoid electromagnetic radiation exceeding the required limits please take note of the
following recommendations.
When Gigabit switching components are found on a PCB (multiplexers, clock recoveries
etc.) any opening of the chassis may produce radiation also at chassis slots other than
that of the device itself. Thus every mechanical opening or aperture should be as small
as possible.
On the board itself every data connection should be an impedance matched line (e.g.
strip line, coplanar strip line). Data, Datanot should be routed symmetrically, vias should
be avoided. A terminating resistor of 100 Ω should be placed at the end of each matched
line. An alternative termination can be provided with a 50 Ω resistor at each (D, Dn). In
DC coupled systems a thevenin equivalent 50 Ω resistance can be achieved as follows:
for 3.3 V: 125 Ω to
and 82 Ω to
, for 5 V: 82 Ω to
and 125 Ω to
V
V
V
V
at Data
CC
EE
CC
EE
and Datanot. Please consider whether there is an internal termination inside an IC or a
transceiver.
In certain cases signal GND is the most harmful source of radiation. Connecting chassis
GND and signal GND at the plate/bezel/chassis rear e.g. by means of a fiber optic
transceiver/cage may result in a large amount of radiation. Even a capacitive coupling
between signal GND and chassis may be harmful if it is too close to an opening or an
aperture.
If a separation of signal GND and chassis GND is not planned, it is strongly
recommended to provide a proper contact between signal GND and chassis GND at
every location where possible. This concept is designed to avoid hotspots. Hotspots are
places of highest radiation which could be generated if only a few connections between
signal and chassis GND exist. Compensation currents would concentrate at these
connections, causing radiation.
By use of Gigabit switching components in a design, the return path of the RF current
must also be considered. Thus a split GND plane of Tx and Rx portion may result in
severe EMI problems.
The cutout should be sized so that all contact springs of the cage make good contact
with the face plate.
For the iSFP transceiver a connection of the SFP cage pins to chassis GND is
recommended. If no separate chassis GND is available on the users PCB the pins
should be connected to signal GND. In this case take care of the notes above.
Please consider that the PCB may behave like a waveguide. With an ε
of 4, the
r
wavelength of the harmonics inside the PCB will be half of that in free space. In this
scenario even the smallest PCBs may have unexpected resonances.
Data Sheet
13
2004-05-17