Jun 3 2010
Maxim Integrated Products has introduced new, advanced transmit/receive integrated circuits (ICs) called the MAX3945 and the MAX3946. The former is a 3.3 V, dual-path limiting amplifier while the latter is a 3.3 V, laser diode driver. The MAX3945 and the MAX3946 are specifically designed for Fibre Channel transmission systems and Ethernet at data rates ranging from 1.0625–11.3 Gbit/s optical fibre links.
The 10GBASE-SR/LR SFP+ chipset allow less than 1W SFP+ optical units. The total energy consumption of the MAX3945 and MAX3946 is approximately 355 mW. Both integrated circuits feature a three-wire digital control interface and digital-to-analog converters (DACs), which help in minimizing external component count.
The MAX3945 has an impedance-mismatch tolerance and limits the signal produced by an amplifier into a current mode logic (CML) level output signal. The MAX3946 is specifically designed to drive a transmitter optical subassembly (TOSA) with a 25Ù flex circuit of about 80 mA bias current and 100 mA modulation current.
The output stage design allows the use of transmitter optical subassemblies to minimize headroom limitations as well as lower module energy usage by 100 mW with 5psP-P deterministic jitter.
The MAX3945 is available in a 3x3 mm, 16-pin TQFN package, while the MAX3946 comes in a 4x4 mm, 24-pin TQFN package.