Microchip Technology, Inc. SY88073L

The SY88073L limiting post amplifier is designed for use in fiber-optic receivers for continuous mode, multi-rate applications from 1Gbps to 12.5Gbps. The SY88073L contains a high-bandwidth, high-sensitivity input stage with user-programmable, wide-range SD assert/LOS de-assert threshold levels, which enables optimized system reach. Typically, 4dB of electrical hysteresis is provided to minimize LOS or SD chattering caused by noisy input signals. A logic level control pin is provided to enable user selection of an open-collector, TTL-compatible LOS or SD status indication signal with an external 5kΩ to 10kΩ pull-up resistor. The SY88073L provides faster SD assert and LOS de-assert times (than typical continuous mode devices) over the entire differential input voltage range of 10mVPP to 1800mVPP. The SY88073L input stage also provides a user-adjustable decision threshold circuit to optimize BER in noisy applications such as WDM, where EDFA and Raman amplifiers contribute uneven noise levels. By applying an external control voltage, the decision threshold can typically be adjusted from 30% to 70% from the nominal 50% threshold when the circuit is disabled. The SY88073L provides integrated 50Ω input and output impedances to optimize the high-speed signal paths and reduce component count. The post amplifier outputs have user-selectable polarity inversion control to simplify PCB layout. A TTL-compatible JAM input is provided to enable a SQUELCH function by feeding back the LOS or SD signal. The JAM input disables only the post amplifier output. The SY88073L operates from a single +3.3V power supply, over temperatures ranging from –40°C to +85°C. For product comparison, please consider: SY88053CL Additional Features Multi-rate operation from 1.0625Gbps to 12.5Gbps Adjustable decision threshold level for offset compensation or BER optimization Wide differential input range (10mVPP to 1800mVPP) Wide SD de-assert or LOS assert threshold range 4.5mVPP to 30mVPP 4dB typical electrical hysteresis Fast SD assert and LOS de-assert times 1µs typical; 2µs maximum Selectable LOS or SD status signal indicator Selectable RXOUT+/RXOUT− polarity inversion TTL-compatible JAM input with internal pull-up Low-noise CML data inputs with integrated 50Ω termination impedance to internal reference VREF Low-noise CML data outputs with integrated 50Ω termination impedance 30ps typical rise/fall times Wide range power supply: 3.3V ±10% Industrial temperature range: -40°C to +85°C Available in a tiny 3mm x 3mm QFN package