te c h t m I7511N tm technology inc. c reate I7511N 1.25gbps fttx laser diode driver/limiting amplifier general description the I7511N is an integrated burst-mode/continuous m ode laser driver and continuous mode limiting amplifier that operates at data rates from 155mbps up to 1.25gbps. the laser driver accepts either positive-referenced emitter coupled logic (p ecl) or current-mode logic (cml) data inputs and provides bias and modulation current for the laser diode. the device can switch the laser diode from a completely dark (off) condition to a full (on) cond ition (with proper bias and modulation currents) in less than 3ns. the I7511N incorporates dc-coupling between laser driver and laser diode. a digital automatic power-control (apc) loop is pro vided to maintain the average optical power over the full temperature range. the receiver also includes a programmable signal-le vel detector, allowing the user to set threshold at which the pecl outputs are enabled. typically 2 .5 db (optical) of hysteresis is provided to preven t chattering when signal level is close to the thresh old. los and jam can be used to implement a squelch func tion, which gives fixed logic levels at data outputs when the input signal is below the programm ed threshold. the I7511N has cmos status outputs (pins los). the I7511N is packaged in a small, 32-pin, 5mm *5mm thin qfn package and consumes only 330mw (typ), excluding bias and modulation currents. applications apon and gepon upstream transmitters passive optical network (pon) transmitters fiber-to-the-home(ftth) and fiber-to-the-premises (f ttp) broadband access systems features integrate laser diode driver and limiting amplifier operation data rate 155mbps and 1.25gbps programmable modulation current from 3ma to 80ma (d c-coupled) programmable modulation current with temperature co mpensation programmable bias current from 1ma to 80ma limiting amplifier includes integrated dc offset ca ncellation circuit polarity control for limiting amplifier data path a nd driver disable input programmable chatter-free signal level detector 4 mv input sensitivity (differential).
|
