FTLX3871DCCxx Product Specification
IX. Digital Diagnostic Specifications
FTLX3871DCCxx transceivers can be used in host systems that require either
internally or externally calibrated digital diagnostics.
Parameter
Symbol
Units Min
Max Accuracy Ref.
Accuracy
Transceiver temperature
Transceiver supply voltage
Transmitter bias current
Transmitter output power
Receiver average optical input
ºC
V
mA
dBm
-10
2.8
0
+75
4.0
127
+5
±5ºC
±3%
±10%
±2dB
1
2
DDTemp
DDVoltage
DDBias
-1
DDTx-Power
dBm
-28
-5
±2dB
DDRx-Power
power
Notes:
1. Internally measured
2. The accuracy of the Tx bias current is 10% of the actual current from the laser driver to the laser
X. SFF-8431 Power-up Sequence
The typical power consumption of the FTLX3871DCCxx may exceed the limit of
1.5W specified for the Power Level II transceivers in [1], for which a power-up sequence
is recommended. However, the FTLX3871DCCxx is factory set to power-up directly to
its operating conditions in Power Level Mode II. Upon request, it can be factory set to
follow the power-up sequence specified for transceivers exceeding 1W, as per [1]. In
power level I, the FTLX3871DCCxx does not carry traffic, but the 2-wire serial
communication is active.
Please refer to [1] and Finisar Application Note AN-2076 for additional details.
XI. Receiver Decision Threshold Control
The host can control the Receiver Decision Threshold (RxDT) of Finisar
FTLX3871DCCxx SFP+ transceivers via the 2-wire serial communication, by setting the
byte 131 of Table 02h. The availability of this function is indicated in Bit 3, Byte 64 of
A0h in the serial ID section. Byte 131 is a 2's complement 7 bit value (-128 - +127) The
decision threshold set is given by:
RxDT = default RxDT + [Byte(131)/256]*100%.
On power-up the byte 131 defaults to 0, corresponding to the RxDT optimum value.
The actual RxDT range the formula covers is about ±20% around the default optimum
value.
Finisar Corporation – September 2015
Rev. C1
Page 8
FINISAR [ FINISAR CORPORATION. ]
