100Gb/s QSFP28 SR4 Transceiver Module

PRODUCT FEATURES  
Up to 27.952 Gbps Data rate per channel
Maximum link length of 150m links on OM4 multimode fiber
High Reliability 850nm VCSEL technology
Electrically hot-pluggable
Digital diagnostic SFF-8636 compliant
Compliant with QSFP28 MSA  
Case operating temperature range:0°C to 70°C  
Power dissipation < 2.0W
APPLICATIONS
100G Ethernet &100GBASE-SR4
ITU-T OTU4
STANDARD
Compliant to IEEE 802.3 bm
Compliant to SFF-8636
RoHS Compliant.

General Description
LAQ2-8485-SR is designed for use in 100 Gigabit per second links over multimode fiber. They are compliant with the QSFP28 MSA and IEEE 802.3bm
The optical transmitter portion of the transceiver incorporates a 4-channel VCSEL (Vertical Cavity Surface Emitting Laser) array, a 4-channel input buffer and laser driver, diagnostic monitors, control and bias blocks. For module control, the control interface incorporates a Two Wire Serial interface of clock and data signals. Diagnostic monitors for VCSEL bias, module temperature, transmitted optical power,received optical power and supply voltage are implemented and results are available through the TWS interface. Alarm and warning thresholds are established for the monitored attributes. Flags are set and interrupts generated when the attributes are outside the thresholds. Flags are also set and interrupts generated for loss of input signal (LOS) and transmitter fault conditions. All flags are latched and will remain set even if the condition initiating the latch clears and operation resumes. All interrupts can be masked and flags are reset by reading the appropriate flag register. The optical output will squelch for loss of input signal unless squelch is disabled. Fault detection or channel deactivation through the TWS interface will disable the channel. Status, alarm/warning and fault information are available via the TWS interface.
The optical receiver portion of the transceiver incorporates a 4-channel PIN photodiode array, a 4-channel TIA array, a 4 channel output buffer, diagnostic monitors, and control and bias blocks. Diagnostic monitors for optical input power are implemented and results are available through the TWS interface. Alarm and warning thresholds are established for the monitored attributes. Flags are set and interrupts generated when the attributes are outside the thresholds. Flags are also set and interrupts generated for loss of optical input signal (LOS). All flags are latched and will remain set even if the condition initiating the flag clears and operation resumes. All interrupts can be masked and flags are reset upon reading the appropriate flag register. The electrical output will squelch for loss of input signal (unless squelch is disabled) and channel de-activation through TWS interface. Status and alarm/warning information are available via the TWS interface.
Absolute Maximum Ratings  
Recommended Operating Conditions
Note:100G Ethernet &100GBASE-SR4 and ITU-T OTU4 has different register setting ,not auto- Negotiatio
Optical Characteristics
Notes:  
Measured with a PRBS 231-1 test pattern, @25.78Gb/s, BER<5.2*10-5.  
Electrical Characteristics
Notes:  
Connected directly to TX data input pins. AC coupled thereafter.  
Into 100Ω ohms differential termination.  
Pin Assignment

Figure 1---Pin out of Connector Block on Host Board
Notes:
1. GND is the symbol for signal and supply (power) common for QSFP28 modules. All are common within the QSFP28 module and all module voltages are referenced to this potential unless otherwise noted. Connect these directly to the host board signal common ground plane.
2. VccRx, Vcc1 and VccTx are the receiving and transmission power suppliers and shall be applied concu