TXP1XGGI2x
Host Board Termination & Coupling
TD+
CML
1µH coil or
INPUTS
ferrite inductor
TD-
20, 22
+1.8V
+3.3V
+
0.1
10
0.1
0.1
RD+
CML
OUTPUTS
1µH coil or
ferrite inductor
RD-
8, 9
+
0.1
10
ASIC/
SerDes
XFP
1µH coil or
+3.3V
R
ferrite inductor
+3.3V
R
+5.0V
6
+
0.1
10
0.1
+3.3V
R
SCL, SDA,
Mod_Abs, Mod_NR,
Interrupt, RX_LOS
All caps are in units of µF
Application Notes
Electrical Interface: All signal interfaces are compliant with
the XFP MSA specification. The high speed DATA interface
is differential AC-coupled internally and can be directly
connected to a 3.3V SERDES IC.
open collector and must be pulled to Host_Vcc on the host
board.
P_Down/RST: The negative edge of Reset Function signal
initiates a complete module reset.
RX_LOS: The Loss of Signal circuit monitors the level of the
incoming optical signal and generates a logic HIGH when an
insufficient photocurrent is produced.
Module Behavior During P_Down and RST: During
execution of a reset (t_init) or while held in Power Down
mode, a module may be unable to determine the correct
value for Mod_NR and RX_LOS. These outputs as well as all
interrupt related flags, except completion of Reset flag, shall
be disregarded by the host. When the module completes
a Reset and is not in Power Down mode, the module must
represent the correct value of both signals on its outputs
before posting a completion of reset interrupt to the host.
TX_Dis: When the TX Disable pin is at logic HIGH, the
transmitter optical output is disabled. (less than -45dBm).
P_Down: The Power Down Function pin, when held High by
the host, places the module in the standby (Low Power) mode
with a maximum power dissipation of 1.5W. This protects
hosts which are not capable of cooling higher power modules
which may be accidentally inserted.The module’s 2-wire serial
interface and all laser safety functions must be fully functional
in this low power mode. During P_Down, the module shall still
support the completion of reset Interrupt, as well as maintain
functionality of the variable power supply.
At no time shall a module cause spurious assertion of the
Interrupt pin. When a host initially applies power to a module
with the P_Down/RST signal asserted, a module comes up in
power down mode.The module shall only assert the Interrupt
signal pin to inform the host it has completed a reset. The
completion of reset flag shall be the only interrupt source flag
set during power down mode. The host is expected to clear
this interrupt before releasing the module from the power
down mode.The transition from power down mode to normal
mode will trigger a reset of the module and result in a 2nd
module reset and a 2nd reset completion interrupt to the host.
Mod_NR: The Mod_NR is an output pin that when High,
indicates that the module has detected a condition that
renders transmitter and or receiver data invalid, shall consist
of logical OR of the following signals:
• Transmit Signal Conditioner Loss of Lock
• Transmitter Laser Fault
Power Supply and Grounding:The power supply line should
be well-filtered. All 0.1μF power supply bypass capacitors
should be as close to the transceiver module as possible.
• Receiver Signal Conditioner Loss of Lock
Other conditions deemed valuable to the detection of fault
may be added to the Mod_NR. The Mod_NR output pin is an
Oplink Communications, Inc
S0131. Rev.03. 2011.03.30
5
