The MAX3274 dual-rate Fibre Channel limiting amplifier is optimized for use in dual-rate 2.125Gbps/1.0625Gbps Fibre Channel optical receiver systems. An on-chip selectable fourth-order Bessel Thompson filter offers 15dB (typ) of attenuation at 2GHz to suppress the relaxation oscillation (RO) found in legacy transmitters. The amplifier accepts a wide range of input voltages and provides constant-level output voltages with controlled edge speeds. Receivers using the MAX3275/MAX3277 transimpedance amplifiers (TIA) and the MAX3274 dualrate limiting amplifier can meet the Fibre Channel receiver sensitivity optical modulation amplitude (OMA) specification of 49mWP-P at 2.125Gbps and 31mWP-P at 1.0625Gbps. Additional features include a programmable threshold loss-of-signal (LOS) detector, output squelch, and bandwidth select. The MAX3274 features current-mode logic (CML) data outputs. The MAX3274 is available in a 16-pin QFN package, making it ideal for GBIC and small form-factor receiver modules.