Avago AFBR-57R5AEZ SFP Digital Diagnostic 4.25 GBd Optical Transceiver

AFBR-57R5AEZ is an optical transceiver that supports high-speed serial links over multimode optical fiber at signaling rates up to 4.25 Gb/s and manufactured by Avago. The Avago AFBR-57R5AEZ SFP 850 nm RoHS Compliant 3.3 V Low Voltage Digital Diagnostic Optical Transceiver is compliant with Small Form Pluggable SFP Multi Source Agreement MSA mechanical and electrical specifications for LC Duplex transceivers, ANSI Fiber Channel FC-PI, FC-PI-2 and com-patible with IEEE 802.3 for gigabit applications. The AFBR-57R5AEZ is electrically interoperable with SFP conformant devices. The Avago AFBR-57R5AEZ SFP supports 4.25, 2.125 and 1.0625 GBd Fiber Channel operations. Read the AFBR-57R5AEZ data sheet for manufacture details and product specifications.

As an enhancement to the conventional SFP interface defined in SFF-8074i, the AFBR-57R5AEZ is compliant to SFF-8472 digital diagnostic interface for optical transceivers. Using the 2-wire serial interface defined in the SFF-8472 MSA, the AFBR-57R5AEZ provides real time temperature, supply voltage, laser bias current, laser average output power and received input power. This information is in addition to conventional SFP base data. The digital diagnostic interface also adds the ability to disable the transmitter TX_DISABLE, monitor for Transmitter Faults TX_FAULT, and monitor for Receiver Loss of Signal RX_LOS.

AFBR-57R5AEZ Applications
• Fiber channel systems: Director class switches, Fabric switches, and HBA cards
• Disk and tape drive arrays

AFBR-57R5AEZ Features
Fully RoHS Compliant
Diagnostic features per SFF-8472 “Diagnostic Monitoring Inter-face for Optical Transceivers”
Real time monitoring of: Transmitted optical power, Received optical power, Laser bias current Temperature and Supply voltage
Wide temperature:  -10°C to 85°C
Supply voltage operation: 3.3 V ± 10%
Transceiver specifications per SFP SFF-8074i Multi-Source Agree-ment and SFF-8472 revision 9.3: 4.25 GBd Fiber Channel operation for FC-PI 400-M5-SN-I and 400-M6-SN-I, 2.125 GBd Fiber Channel operation for FC-PI 200-M5-SN-I and 200-M6-SN-I, and 1.0625 GBd Fiber Channel operation for FC-PI 100-M5-SN-I and 100-M6-SN-I
Link lengths at 4.25 GBd: 150 m with 50 µm MMF, 70 m with 62.5 µm MMF
Link lengths at 2.125 GBd: 300 m with 50 µm MMF, 150 m with 62.5 µm MMF
Link lengths at 1.0625 GBd: 500 m with 50 µm MMF, 300 m with 62.5 µm MMF
LC Duplex optical connector interface conforming to ANSI TIA/EIA604-10 FOCIS 10
850 nm Vertical Cavity Surface Emitting Laser VCSEL source technology
IEC 60825-1 Class 1/CDRH Class 1 laser eye safe
Compatible with Gigabit Ethernet
Enhanced EMI performance for high port density applications 

The AFBR-57R5AEZ installs in any SFF-8074i compliant SFP port, regardless of host equipment operating status. The AFBR-57R5AEZ is hot-pluggable, allowing the SFP installation while the host system is operating. Upon insertion, the AFBR-57R5AEZ transceiver housing makes initial contact with the host board SFP cage, mitigating potential damage due to Electro-Static Discharge ESD.

The AFBR-57R5AEZ digital diagnostic interface and serial identification via a 2-wire serial interface based on ATMEL AT24C01A series EEPROM protocol and signaling detail. Conventional EEPROM memory, bytes 0-255 at memory address 0xA0, for compliance with SFF-8074i. New digital diagnostic information, bytes 0-255 at memory address 0xA2, is compliant to SFF-8472. The new diagnostic information provides the opportunity for Predictive Failure Identification, Compliance Prediction, Fault Isolation and Component Monitoring.

The AFBR-57R5AEZ predictive failure feature allows a host to identify potential link problems before impacting system performance. Prior identification of link problems enables a host to service an application via “fail over” to a redundant link or replace a suspect device, maintaining system uptime in the process. For applications where system uptime is mandatory, a digital SFP provides a means to monitor two real-time laser metrics associated with observing laser degradation and predicting failure: average laser bias current Tx_Bias and average laser optical power Tx_Power.

The AFBR-57R5AEZ ensures compliance prediction by its ability to determine if an optical transceiver is operating within its operating and environmental requirements. AFBR-57R5AEZ devices provide real-time access to transceiver internal supply voltage and temperature, allowing a host to identify potential component compliance issues. Received optical power is also available to assess compliance of a cable plant and remote transmitter. When operating out of requirements, the link cannot guarantee error free transmission.

The AFBR-57R5AEZ fault isolation feature allows a host to quickly pinpoint the location of a link failure, minimizing downtime. For optical links, the ability to identify a fault at a local device, remote device or cable plant is crucial to speeding service of an installation. AFBR-57R5AEZ real-time monitors of Tx_Bias, Tx_Power, Vcc, Temperature and Rx_Power can be used to assess local transceiver current operating conditions. In addition, status flags Tx_Disable and Rx Loss of Signal LOS are mirrored in memory and available via the two-wire serial interface.

The transmitter section consists of the Transmitter Optical Subassembly TOSA and laser driver circuitry. The TOSA, containing an 850 nm VCSEL (Vertical Cavity Surface Emitting Laser) light source, is located at the optical interface and mates with the LC optical connector. The TOSA is driven by a custom IC which uses the incoming differential high speed logic signal to modulate the laser diode driver current. This Tx laser driver circuit regulates the optical power at a constant level provided the incoming data pattern is dc balanced.

The AFBR-57R5AEZ accepts a TTL and CMOS compatible transmit disable control signal input (pin 3) which shuts down the transmitter optical output. A high signal implements this function while a low signal allows normal transceiver operation. In the event of a fault, cycling this control signal resets the module as depicted in Figure 4. An internal pull up resistor disables the transceiver transmitter until the host pulls the input low. Host systems should allow a 10 ms interval between successive assertions of this control signal. Tx_Disable can also be asserted via the two-wire serial interface at address A2h, byte 110, bit 6 and monitored at address A2h, byte 110, bit 7.

The contents of A2h, byte 110, bit 6 are logic OR’d with hardware Tx_Disable (pin 3) to control transmitter operation.

A catastrophic laser fault will activate the transmitter signal, TX_FAULT, and disable the laser. This signal is an open-collector output (pull-up required on the host board). A low signal indicates normal laser operation, and a high signal indicates a fault. The TX_FAULT will detach when a laser fault occurs and cleared by toggling the TX_DISABLE input or power cycling the transceiver. The transmitter fault condition can also be monitored via the two-wire serial interface (address A2, byte 110, bit 2).

The receiver section includes the Receiver Optical Sub-Assembly (ROSA) and the amplification/quantization circuitry. The ROSA, containing a PIN photodiode and custom transimpedance amplifier, is located at the optical interface and mates with the LC optical connector. The ROSA output is sent to a custom IC that provides post-amplification and quantization.

The post-amplification IC also includes transition detection circuitry which monitors the ac level of incoming optical signals and provides a TTL/CMOS compatible status signal to the host (pin 8). An adequate optical input results in a low Rx_LOS output while a high Rx_LOS output indicates an unusable optical input. The Rx_LOS thresholds are factory set so that a high output indicates a definite optical fault has occurred. Rx_LOS can also be monitored via the two-wire serial interface (address A2h, byte 110, bit 1).

The AFBR-57R5AEZ interfaces with the host circuit board through twenty I/O pins SFP electrical connector.

The AFBR-57R5AEZ high speed transmit and receive interfaces require SFP MSA compliant signal lines on the host board. To simplify board requirements, biasing resistors and ac coupling capacitors are incorporated into the SFP transceiver module per SFF-8074i, and not required on the host board. The Tx_Disable, Tx_Fault, and Rx_LOS lines require TTL lines on the host board per SFF-8074i if used. If an application chooses not to take advantage of the functionality of these pins, care must be taken to ground Tx_Disable for normal operation.