Evaluation Printed Circuit Board
The AFBR-775BxxxZ/785BxxxZ transmit/receive pair are high-performance fiber optic modules manufactured for parallel data communication applications over 50/125 mm MM optical fiber. At data rates from 1 to 6.25 Gbps per channel these modules are suitable for applications requiring up to 75 Gbps aggregate bandwidth. Each transmitter/receiver pair completes a robust communication link across 150 meters of optical fiber useful in many datacom and telecom switch and router back-plane connections.
This application note is intended for use in conjunction with the device data sheet for the respective transmit/receive pair, which is available from your Avago Technologies representative. The data sheet provides a detailed description of the modules operation, signal descriptions and maximum ratings. It is recommended that the block diagrams, pin definitions, and maximum ratings from the data sheet be reviewed prior to testing.
Recommended Equipment List
Test Equipment Included in Sample Kit:
12-Channel Pluggable Tx Evaluation Board
12-Channel Pluggable Rx Evaluation Board
Avago Technologies AFBR-775BxxxZ/785BxxxZ Data Sheet
Application Note 5304
Test Equipment Not Included in Sample Kit:
3.3 V dc -Power Supply(s) 2.5 V dc -Power Supply(s)
12-fiber Multimode Fiber Optic Ribbon Cable with MTP® Connectors
12-fiber Multimode Fiber Optic Breakout-Cable with MTP®-to-SC connectors
86100A Agilent Digital Communications Analyzer (DCA)
Agilent 83487A Opt H21 DCA Plug-In (or equivalent)
Agilent ParBERT 81250 (or equivalent Bit Error Rate Tester)
Variable Fiber Optic Attenuator
Optical Power Meter (multimode, 850nm capable)
81002FF Integrating Sphere Adapter (recommended High-frequency coaxial cables with SMA connectors (x48)
Evaluation Board Description
Electrical connections from the modules to their respective evaluation PCB are achieved through a 100 pin (10x10) MEG-Array® plug-receptacle. This high-density connector enables the user to easily interchange modules allowing testing of many device pairs using only one set of evaluation boards. The robust design of these pluggable modules allows for repeated plugging and unplugging of the modules up to 50 times without degradation in the receptacle electrical integrity.
Please note that these modules are electrically sensitive devices and are NOT intended for “hot-plug” applications. The power supply to the evaluation boards should be turned OFF prior to plugging or unplugging the devices. “Hot plugging” these devices is not recommended and may result in excessive voltage and or inrush current that exceeds the device limits and may cause damage.
These evaluation boards provide access to all transmit and receive high-speed I/O’s through straight PCB mount SMA connectors. All of the high-speed differential data I/O have 100 nF ac-coupling capacitors on the evaluation boards (ac-coupling is recommended for these modules). The power supplies (2.5V and 3.3V) can be applied through BNC connectors on each board.
Mating Directions
Ensure the connector assemblies are clean and free of contaminants prior to mating. Locate and match the connector’s position marking (D) for both the Plug and Receptacle. Also ensure that the power (both 3.3V and 2.5V) are not turned on. This will result in the correct orientation of the modules with regard to the evaluation boards. Rough alignment is required prior to connector mating as misalignment of > 0.8 mm could damage the connector contacts. The receptacle is keyed for rough alignment. Application of mating forces should originate from one side of the connector then proceed to the other side of the connector. See Figure 1.
Figure 1 Mating Forces
Unmating Directions
Release any fasteners holding the assembly together.
Turn off the voltage to the module (both 2.5V and 3.3V ).
Force applied during connector unmating needs to originate from the alignment slot/key end of the assembly.
Unmating the connector perpendicular to the alignment slot/key may cause damage to the terminal contacts. See Figure 2.
Figure 2 Un-Mating Forces
It should be noted that the transmitter and receiver modules are keyed in such a way that connecting a transmitter module to a receiver footprint or evaluation board and vice-versa is prevented.
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