56Gb/s PAM4 DML Driver, Gen2

The HXT44420 is a quad, low-power, linear PAM4 Directly Modulated Laser (DML) driver for LR applications. It supports signaling rates up to 28GBuad or 56Gbps PAM4. In conjunction with an individual DML, the HXT44420 handles the complete electrical-to-optical conversion, including CML input with equalization, laser bias and modulations, laser power control, and supervision.

The HXT44420 also integrates several functions required for Automatic Power Control (APC), as well as internal and module temperature measurements and reporting. With an additional RSSI input, one can directly measure the module receive optical power and report it.

HXT44420 is designed as a directly DC-coupled die used in a Transmitter Optical Sub-Assembly (TOSA) application. Thus, one can reduce the number of discrete components for better RF performance, and cost-effective and compact assemblies.