SI5040-D-GM Silicon Laboratories Inc, SI5040-D-GM Datasheet - Page 19

• Manufacturer Part Number: SI5040-D-GM
• Description: IC TXRX XFP 10GBPS 32LGA
• Manufacturer: Silicon Laboratories Inc

Specifications of SI5040-D-GM

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

5.2. Limiting Amplifier
The Si5040 incorporates a high-sensitivity differential
limiting amplifier with sufficient gain to allow direct
connection to a transimpedance amplifier. The amplifier
has a guaranteed sensitivity of 8 mVppd.
5.3. Receive Amplitude Monitor
The Si5040 limiting amplifier includes circuitry that
monitors the amplitude of the receiver differential input
signal (RXDIN). The amplitude value can be read from
the Peakdet register (Register 16). The receiver signal
amplitude monitoring circuit is also used in the
generation of the loss-of-signal alarm (LOS).
5.4. Receiver Loss of Signal Alarm (LOS)
The Si5040 receiver generates a loss-of-signal alarm
when the input signal fails to meet the selected
programmable condition for loss of signal. The
programmable LOS mode is controlled in the RxlosCtrl
register (Register 10). The programmable modes are
Analog Loss Of Signal (ALOS), Digital Loss of Signal
(DLOS), and Signal Quality Monitor (SQM). As shown in
Figure 15, one or more of these alarm signals is
logically combined into the Receiver Loss of Signal
(RX_LOS) alarm pin (Pin 3). The state of the RX_LOS
alarm pin will also be reflected in the LOS bit in the
RxAlarmStatus register (Register 9). LOS may also be
configured to generate an interrupt. The status of the
LOS interrupt bit may be read in the RxintStatus register
(Register 5). The status of the various LOS modes is
stored in the losStatus register (Register 11).
Is CID > (dLosAssertThresh *5 +2) *1024
Figure 10. Algorithm to Set dLOS
CID (Continuous
Identical Digits)
Set dLos
Yes
Monitor
Rev. 0.86
An ALOS alarm occurs when the peak-to-peak signal
amplitude on the RXDIN input is below the threshold
value set in the aLosThresh register (Register 12). The
level may be set from 10 to 400 mV in 1 mV increments.
The amount of hysteresis applied to ALOS is set in the
aLosThresh2 register (Register 13) up to a maximum of
“aLoSThresh+”
“aLoSThresh+” 3 dB. The analog LOS function is
enabled by setting bit 0 in the RxLosCtrl register
(Register 10). Note that the peak-to-peak detector and
ALOS detection are designed to work with pseudo-
random dc-balanced data band limited to <2 GHz.
A DLOS alarm occurs when the receive bit stream
consists of a run length of 1s or 0s greater than the
value loaded in the RxdLosAssertThresh register
(Register 17). DLOS will remain asserted until the data
shows activity for a time greater than that loaded in the
RxdLOSClearThresh register (Register 18). Refer to
Figure 10 and Figure 11 for algorithm flowcharts.
An SQM alarm occurs when the estimate of the receive
signal quality falls below the value loaded in
RxsqmThresh (Register 26). The Signal Quality Monitor
measures the magnitude of the horizontal eye opening
of the received signal. The SQM value can be read from
the RxsqmValue register (Register 25). An SQM alarm
will assert if the RxsqmEn bit has been set in the
RxsqmConfig register (Register 26). SQM hysteresis is
set in the RxsqmDeassertThresh register (Register 27).
6 dB.
No
The
default
Si5040
value
19
is