Low-Power, 622Mbps to 3.2Gbps Limiting Amplifier

The MAX3746 multirate limiting amplifier functions as a data quantizer for SONET, Fibre-Channel, and Gigabit Ethernet optical receivers. The amplifier accepts a wide range of input voltages and provides selectable-level, current-mode logic (CML) output voltages with controlled edge speeds. A received-signal-strength indicator (RSSI) is available when the MAX3746 is DC-coupled to the MAX3744/MAX3724 SFP transimpedance amplifier (TIA). A receiver consisting of the MAX3744/MAX3724 and the MAX3746 can provide up to 19dB RSSI dynamic range. Additional features include a programmable loss-of-signal (LOS) detect, an optional disable function (DISABLE), and an output-signal polarity reversal (OUTPOL). Output disable can be used to implement squelch.

The combination of the MAX3746 and the MAX3744/MAX3724 allows for the implementation of all the small-form-factor SFF-8472 digital diagnostic specifications using a standard 4-pin TO-46 header.

The MAX3746 is pin-for-pin compatible with the MAX3748A limiting amplifier and consumes 30% less power. The MAX3746 is packaged in a 3mm x 3mm, 16-pin QFN package.

Applications

* Fibre Channel SFF/SFP Transceiver Modules * Gigabit Ethernet SFF/SFP Transceiver Modules * Multirate OC-12 to OC-48 FEC SFF/SFP * Transceiver Modules

* SFP Reference Design Available

* Low 115mW Power Consumption

* 16-Pin QFN Package with 3mm x 3mm Footprint

* 70ps Rise and Fall Time

* Loss-of-Signal with Programmable Threshold

* RSSI Interface (with MAX3744/MAX3724 TIA)

* Output Disable

* Polarity Select

* 8.4psP-P Deterministic Jitter (3.2Gbps)

* Improved EMI Performance

* Selectable CML Output levels

* Pin Compatible with MAX3748A