Features ◊ Support 4x25GBASE-SR application ◊ Compliant to QSFP28 MSA SFF-8636 and SFP28 MSA SFF-8431 and SFF- 8472 ◊ Multi rate of up to 25.78125Gbps per lane ◊ Transmission distance up to 50m ◊ +3.3V single power supply ◊ Low power consumption ◊ UL certification cables (optional) ◊ Operating  temp Commercial: 0°C to +70 °C ◊ RoHS compliant Applications ◊ 4x25Gbe-SR ◊ Other optical links Specification: Absolute Maximum Ratings Table1- Absolute Maximum Ratings       Parameter Symbol Min. Typical Max. Unit Notes Supply Voltage Vcc3 -0.5 - +3.6 V   Storage Temperature Ts -10 - +70 °C   Operating Humidity RH +5 - +85 % 1 Note: 1 No condensation Recommended Operating Conditions Table 2- Recommended operating Conditions Parameter Symbol Min. Typical Max. Unit Notes Operating  Temperature TC 0 - +70 °C   Power Supply Voltage Vcc 3.14 3.3 3.47 V   Power Dissipation per QSFP28 Pd - - 2.5 W   Power Dissipation per SFP28 Pd - - 1.0 W 1 Bit Rate  per Lane BR 10.3125 25.78125 - Gbps   Note: 1 Per terminal Electrical Characteristics Table 3- Electrical Characteristics for QSFP28 Parameter Symbol Min. Typ. Max. Units Notes  ModSelL Module Select VOL 0 - 0.8 V   Module Unselect VOH 2.5 - VCC V    LPMode Low Power Mode VIL 0 - 0.8 V   Normal Operation VIH 2.5 - VCC+0.3 V    ResetL Reset VIL 0 - 0.8 V   Normal Operation VIH 2.5 - VCC+0.3 V   ModPrsL Normal Operation VOL 0 - 0.4 V    IntL Interrupt VOL 0 - 0.4 V   Normal Operation VoH 2.4 - VCC V   Electrical Transmitter Characteristics Differential Date Input Swing Vin,P-P 200 - 1600 mV   Output Differential Impedance ZIN 90 100 110 Ω   Electrical Receiver Characteristics Differential Data Output Swing Vout 200 - 800 mVPP   Bit Error Rate BER     E-12   1 Input Differential Impedance ZD 90 100 110 Ω   Note: 1 PRBS2^31-1@25.78125Gbps Table 4- Electrical Characteristics for SFP28 Parameter Symbol Min. Typ. Max. Units Notes Electrical Transmitter Characteristics Differential Data Input Swing Vin,P-P 200 - 1600 mVPP   Input Differential Impedance ZIN 90 100 110 Ω    Tx_Fault Normal Operation VOL 0 - 0.8 V   Transmitter Fault VOH 2.0 - VCC V    Tx_Disable Normal Operation VIL 0 - 0.8 V   Laser Disable VIH 2.0 - VCC+0.3 V   Electrical Receiver Characteristics Differential Date Output Vout 400 - 800 mV   Bit Error Rate BER - - E-12 -   Output Differential Impedance ZD 90 100 110 Ω    Rx_LOS Normal Operation VOL 0 - 0.8 V   Lose Signal VoH 2.0 - VCC V   Pin arrangement                Figure 1, Pin View for QSFP28 Table 5- Pin Function Definitions for QSFP28 Pin Symbol Name/Description Notes 1 GND Ground 1 2 Tx2n Transmitter Inverted Data Input   3 Tx2p Transmitter Non-Inverted Data Input   4 GND Ground 1 5 Tx4n Transmitter Inverted Data Input   6 Tx4p Transmitter Non-Inverted Data Input   7 GND Ground 1 8 ModSelL Module Select   9 ResetL Module Reset   10 Vcc Rx +3.3V Power Supply Receiver   11 SCL 2-wire serial interface clock   12 SDA 2-wire serial interface data   13 GND Ground 1 14 Rx3p Receiver Non-Inverted Data Output   15 Rx3n Receiver Inverted Data Output   16 GND Ground 1 17 Rx1p Receiver Non-Inverted Data Output   18 Rx1n Receiver Inverted Data Output   19 GND Ground 1 20 GND Ground 1 21 Rx2n Receiver Inverted Data Output   22 Rx2p Receiver Non-Inverted Data Output   23 GND Ground 1 24 Rx4n Receiver Inverted Data Output     Pin Symbol Name/Description Notes 25 Rx4p Receiver Non-Inverted Data Output   26 GND Ground 1 27 ModPrsL Module Present   28 IntL Interrupt   29 Vcc Tx +3.3V Power supply transmitter   30 Vcc1 +3.3V Power supply   31 LPMode Low Power Mode   32 GND Ground 1 33 Tx3p Transmitter Non-Inverted Data Input   34 Tx3n Transmitter Inverted Data Input   35 GND Ground 1 36 Tx1p Transmitter Non-Inverted Data Input   37 Tx1n Transmitter Inverted Data Input   38 GND Ground 1 Note: 1. Circuit ground is internally isolated from chassis ground.   Figure 2, Pin View for SFP28 Table 6-Pin Function Definitions Pin Symbol Name/Description Notes 1 VEET Module Transmitter Ground 1 2 TX_FAULT Module Transmitter Fault 2 3 TX_DISABLE Transmitter Disable; Turns off transmitter laser output 3 4 SDA 2-Wire Serial Interface Data Line (MOD-DEF2)   5 SCL 2-Wire Serial Interface Clock (MOD-DEF1)   6 MOD_ABS Module Absent, connected to VEET or VEER in the module 2 7 RS0 Rate Select 0, optionally controls SFP+ module receiver 4 8 RX_LOS Receiver Loss of Signal Indication (In FC designated as Rx_LOS and in Ethernet designated as NOT Signal Detect) 2 9 RS1 Rate Select 1, optionally controls SFP+ module transmitter 4   Pin Symbol Name/Description Notes 10 VEER Module Receiver Ground 1 11 VEER Module Receiver Ground 1 12 RD- Receiver Inverted Data Output   13 RD+ Receiver Non-Inverted Data Output   14 VEER Module Receiver Ground 1 15 VCCR Module Receiver 3.3 V Supply   16 VCCT Module Transmitter 3.3 V Supply   17 VEET Module Transmitter Ground 1 18 TD+ Transmitter Non-Inverted Data Input   19 TD- Transmitter Inverted Data Input   20 VEET Module Transmitter Ground 1 Note: The module ground pins are isolated from the module case. The pins shall be pulled up with 4.7K-10Kohms to a voltage between 3.14V and 3.46V on host board. The pin is pulled up to VCCT with a 4.7K-10KΩ resistor in the module. See SFF-8472 Rev12.2 Table 10-2.   Recommended Circuit Figure 3, Recommended Interface Circuit for QSFP28   Figure 4, Recommended Host Board Power Supply Circuit for SFP28   Figure 5, Recommended Interface Circuit for SFP28   Monitoring Specification   Figure 6, Memory Map for QSFP28                        Figure 7, Memory Map for SFP28 Mechanical Unit mm             Figure 8, Mechanical Diagram Table 7- Cable Length Cable Length  L1（Unit: m） Tolerant（Unit: cm） ≤1.0 +5/-0 1.0＜L≤4.5 +15/-0 4.5＜L≤14.5 +30/-0 ＞14.5 +2%/-0 Table 8- Breakout Cable Nominal Length Total Length L1 (Unit: m) Breakout Point Measured from SFPL2(Unit: m) 1 0.7 2 1.4 3 2 ≥5 3 Warnings Handling Precautions: This device is susceptible to damage as a result of electrostatic discharge (ESD). A static free environment is highly recommended. Follow guidelines according to proper ESD procedures. Laser Safety: Radiation emitted by laser devices can be dangerous to human eyes. Avoid eye exposure to direct or indirect radiation.