Vi-Link SFP+ SR module electrical interface is compliant with SFI electrical specifications. The transmitter input and receiver output impedance are 100 Ohms differential. Data lines are internally AC coupled. The module provides differential termination and reduces differential to common mode conversion for quality signal termination and low EMI.
The transmitter converts from 1.2 Gbit/s to 10Gbit/s serial PECL or CML electrical data into serial optical data compliant with the 10GBASE-SR standard. An open collector compatible Transmit Disable (Tx Dis) is provided. A logic “1,” or no connection on this pin will disable the laser from transmitting. A logic “0” on this pin provides normal operation. The transmitter has an internal automatic power control loop (APC) to ensure constant optical power output across supply voltage and temperature variations. An open collector compatible Transmit Fault (TFault) is provided. TX Fault is a module output contact that when high, indicates that the module transmitter has detected a fault condition related to laser operation or safety. The TX Fault output contact is an open drain/collector and shall be pulled up to the Vcc Host in the host with a resistor in the range 4.7-10 kΩ. TX Disable is a module input contact. When TX Disable is asserted high or left open, the SFP+ module transmitter output shall be turned off. This pin shall be pulled up to VccT with a 4.7 kΩ to 10 kΩ resistor.
The receiver converts 10Gbit/s serial optical data into serial PECL/CML electrical data. An open collector compatible Loss of Signal is provided. Rx LOS when high indicates an optical, signal level below that specified in the relevant standard. The Rx LOS contact is an open drain/collector output and shall be pulled up to Vcc Host in the host with a resistor in the range 4.7-10 kΩ, or with an active termination. Power supply filtering is recommended for both the transmitter and receiver. The Rx LOS signal is intended as a preliminary indication to the system in which the SFP+ is installed that the received signal strength is below the specified range. Such an indication typically points to non-installed cables, broken cables, or a disabled, failing, or powered-off transmitter at the far end of the cable. The physical IC can also be accessed via a 2-wire serial bus at address A0h.