The DS1862 is a closed-loop laser-driver control IC with
built-in digital diagnostics designed for XFP MSA. The
laser control function incorporates average power con-
trol (APC) and allows extinction ratio control though a
temperature indexed look-up table (LUT). The DS1862
monitors up to seven analog inputs, including tempera-
ture and monitor diode (MD) current, which are used to
regulate the laser bias current and extinction ratio.
Warning and alarm thresholds can be programmed to
generate an interrupt if monitored signals exceed toler-
ance. Calibration is also provided internally using inde-
pendent gain and offset scaling registers for each of
the monitored analog signals. Settings such as pro-
grammed calibration data are stored in password-pro-
tected EEPROM memory. Programming is accomplished
through an I2C-compatible interface, which can also be
used to access diagnostic functionality.