The SFP Reference Design Kit(SFP-RDK) provides a complete optical transceiver chipset and system-level solution for designers. The SFP-RDK includes:
- SFP Transceiver Module Board
- SFP Host Board
- JTAG Adapter board
- PCB Schematics
- PCB Layout , Gerber Files, CAD Files
- Bill of Materials
- SFP Firmware Source Code in ANSI C
- Evaluation GUI software
- Applications Note(AN-706), User Manuals
The SFP-RDK consists of Analog Devices’ optical transceiver chip set: the ADN2870 dual loop laser driver, the ADN2880/2 Transimpedance amplifier, the ADN2891/2 Limiting amplifier and the ADuC7020 MicroConverter . Use of the micro-controller allows
flexible module designs support user definable functions.
参考设计的特性:
Small Form-factor Pluggable (SFP) MSA compliant
SFF-8472 Digital Diagnostic Monitoring
Multi-Rate from 155Mbps to 4.25Gbps
Internal Calibration
Closed-Loop control of extinction ratio(ADN2870)
Build-in LOS/RSSI detectors (ADN2891/2)
Embedded MCU, MicroConverter (ADuC7020):
- 16/32-bit RISC ARM7TDMI core, 45MIPS peak
- 5 channels 12-bit ADC
- 4 x 12-bit DACs
- On-chip Power Supply Monitor
- On-chip Temperature Monitor
- Programmable Logic Array
- 62K Bytes EEPROM, 8K Bytes SRAM
- Four I2C Device Addressing
应用:
Multi-rate OC-3 to OC-48FEC SFP/SFF Modules
1x/2x/4x Fibre Channel Modules
Gigabit Ethernet Modules
下面是单端激光驱动系统方框图:
SFP参考设计所包括的内容:
Contents of SFP Reference Design Kit Package
The SFP-RDK package contains the following items.
- SFP Module Board with TOSA and ROSA
- SFP Host Board
- GUI Adapter Board (RS232-to-I2C, ADuC7020-MiniEval)
- JTAG Adapter Board
- RS-232 Cable (MicroConverter Dongle Cable)
- Test Report
- CD containing:
Firmware source files
GUI software files
GUI driver files
下图是SFP参考设计外形图:
下面是SFP参考设计所用的元件的性能介绍:
1.ADUC7020 Precision Analog Microcontroller, 12-Bit Analog I/O, ARM7TDMI? MCU
The ADuC7019/20/21/22/24/25/26/27/28 are fully integrated, 1 MSPS, 12-bit data acquisition systems incorporating high performance multichannel ADCs, 16-bit/32-bit MCUs, and Flash/EE memory on a single chip.
The ADC consists of up to 12 single-ended inputs. An additional four inputs are available but are multiplexed with the four DAC output pins. The four DAC outputs are only available on certain models (ADuC7020 and ADuC7026). However, in many cases where the DAC outputs are not present, these pins can still be used as additional ADC inputs, giving a maximum of 16 ADC input channels. The ADC can operate in single-ended or differential input modes. The ADC input voltage is 0 V to VREF. A low drift band gap reference, temperature sensor, and voltage comparator complete the ADC peripheral set.
Depending on the part model, up to four buffered voltage output DACs are available on-chip. The DAC output range is programmable to one of three voltage ranges.
The devices operate from an on-chip oscillator and a PLL generating an internal high frequency clock of 41.78 MHz. This clock is routed through a programmable clock divider from which the MCU core clock operating frequency is generated. The microcontroller core is an ARM7TDMI, 16-bit/32-bit RISC machine, which offers up to 41 MIPS peak performance. Eight kilobytes of SRAM and 62 kilobytes of nonvolatile Flash/EE memory are provided on-chip. The ARM7TDMI core views all memory and registers as a single linear array.
Applications:
Industrial control and automation systems
?
Smart sensors, precision instrumentation
?
Base station systems, optical networking
ADuC7020的功能方框图:
下面是ADuC7020评估板电路图:
ADuC7020 Evaluation Board Schematic
2. ADN2870 3.3 V, Dual Loop, 50 Mbps to 3.3 Gbps Laser Diode Driver
The ADN2870 uses a dual loop control algorithm to control both average power and extinction ratio of the laser diode (LD), eliminating the need for expensive temperature calibration or look-up tables for laser control. The average power and extinction ratio can be voltage set controlled by a microcontrollers voltage DACs or can be resistor set controlled. External component count and PCB area are low as both power and extinction ratio control are fully integrated. A programmable alarm is provided for laser fail (end of life) and bias current monitoring is provided for external control. The product is fully compliant to the SFP digital diagnostics specification, SFF-8472. The ADN2870 is part of a complete SFP chip set solution from ADI that supports datarates from OC-3 to 4X Fiberchannel.
Applications:
SONET OC-3,12,48 SFP/SFF Modules
1X, 2X, 4X Fiber Channel Modules
Multirate OC-3 to OC-48 Modules
?
DWDM and CWDM SFP Modules LX4 Modules
?
ADN2870激光二极管驱动电路图:
3. ADN2880 3.2 Gbps 3.3V Low Noise TIA for Small Form Factors
The ADN2880 is a compact, high performance 3.3 V power supply SiGe transimpedance amplifier (TIA) optimized for small form factor Metro-Access and Ethernet PIN/APD-TIA modules operating up to 3.2Gbps. It is a single chip solution for detecting photodiode current with a differential output voltage.
The ADN2880 features low input referred noise current of 400 nA enabling -24 dBm sensitivity; 2.1 GHz minimum BW enables up to 2.7 Gbps operation; +3.25 dBm nominal operation at 10 dB extinction ratio.
To facilitate assembly in small form factor packages such as a TO-CAN, the ADN2880 integrates a photodiode filter network on chip and features 20 kHz low frequency cutoff without any external components.
The ADN2880 operates with a 3.3 Volt power supply and is available in die form, with a chip area of less than 1 mm2.
Applications
?PIN/APD-TIA Receive Optical Sub-Assemblies
?Up to 3.2Gbps LX4/GbE/FC Optical Receivers, Transceivers,
Transponders
ADN2880功能方框图:
4. ADN2892 3.3 V 4.25 Gb/s Limiting Amplifier
The ADN2892 is a high gain, limiting amplifier optimized for use in Fibre Channel and GbE optical receivers. The ADN2892 accepts input levels of up to 2.0 V p-p differential and has 3 mV p-p differential input sensitivity. The ADN2892 provides the receiver functions of quantization and loss of signal (LOS) detection.
The ADN2892 has an on-chip selectable filter to reduce the BW of the limamp to 1.5GHz in order to filter out the relaxation oscillation of legacy 1Gb/s Fiber Channel transmitters with CD lasers. The reduced BW will also allow for more optical Rx sensitivity margin at the lower data rates such as 1xFC and 1GbE in multi-rate modules.
The limiting amplifier also measures average received power based on a direct measurement of the photodiode current with better than 1 dB of accuracy over the entire input range of the receiver. This eliminates the need for external average Rx power detection circuitry in SFF-8472 compliant optical transceivers.
The ADN2892 limiting amplifier operates from a single 3.3 V supply, has low power dissipation, and is available in a spacesaving 3 x 3 mm 16-lead lead frame chip scale package (LFCSP).
Applications
?SFP/SFF/GBIC optical transceivers
?1x/2x/4x Multi-rate Fibre Channel receivers
?LX4
?WDM transponders
ADN2892功能方框图:
来源：中电网
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