
Micrel
General Description
The MIC3000 enables the implementation of sophisticated, hot-pluggable fiber optic transceivers with intelligent laser control and Digital Diagnostic Monitoring Interface per SFF-8472. It essentially integrates all non-datapath functions of an SFP transceiver into a tiny 4mm × 4mm MLF™ package. It also works well as a microcontroller peripheral in transpon ders or 10Gbps transceivers.
A highly configurable automatic power control (APC) circuit controls laser bias. Bias and modulation are temperature compensated using dual DACs, an on-chip temperature sensor, and NVRAM look-up tables. A programmable internal feedback resistor provides unprecedented dynamic range for APC. Controlled laser turn-on facilitates hot-plugging. An analog-to-digital converter converts the measured temperature, voltage, bias current, transmit power, and received power from analog-to-digital. Each parameter is compared against user-programmed warning and alarm thresholds. Analog comparators and DACs provide high-speed monitoring of received power and critical laser operating parameters.
An interrupt output, power-on hour meter, and data-ready bits add user friendliness beyond SFF-8472. The interrupt output and data-ready bits reduce overhead in the host system. The power-on hour meter logs operating hours using an internal real-time clock and stores the result in NVRAM.
Communication with the MIC3000 is via an industry standard 2-wire serial interface. Nonvolatile memory is provided for serial ID, configuration, and separate OEM and user scratchpad spaces. Two-level password protection guards against data corruption.
FEATUREs
• APC or constant-current laser bias
• Supports multiple laser types and bias circuit topologies
• Drives external low-cost BJT for laser bias
• Integrated digital temperature sensor
• Temperature compensation of modulation, bias, and fault levels via NVRAM look-up tables
• Direct interface to SY88932, SY88982, SY89307 and other drivers
• NVRAM to support GBIC/SFP serial ID function
• User writable EEPROM scratchpad
• Diagnostic monitoring interface per SFF-8472
– Monitors and reports critical parameters: temperature, bias current, TX and RX optical power, and supply voltage
– S/W control and monitoring of TXFAULT, RXLOS, RATESELECT, and TXDISABLE
– External calibration
• Power-on hour meter
• Interrupt capability
• Extensive test and calibration features
• 2-wire I2C compatible serial interface
• SFP MSA and SFF-8472 compliant
• 3.0V to 3.6V power supply range
• 5V-tolerant I/O
• 4mm × 4mm 24-pin MLF™ package
APPLICATIONs
• SFF/SFP optical transceivers
• SONET/SDH transceivers and transponders
• Fibre channel transceivers
• 10Gbps transceivers
• Free space optical communications
• Proprietary optical links