资 源 简 介
The EL6173 is a high performancethree-channel laser driver thatprovides controlled current to agrounded laser diode. Write channels 2 and 3 can provideup to 200mA per channel of DC or pulsed current, withswitching speeds of approximately one nanosecond rise/fallTIme. All three channels are summed together at the IOUToutput, allowing the user to create mulTIlevel waveforms inorder to opTImize laser diode performance. The level of theoutput current is set by an analog voltage applied to anexternal resistor which converts the voltage into a current atthe IIN pin (virtually ground). The current seen at this pin isthen amplified to become a current source at pin IOUT.An on-chip 500MHz oscillator is provided to allow outputcurrent modulaTIon when in any mode. This is turned onwhen the OSCEN pin is held high. Complete control ofamplitude and frequency is set by two external resistorsconnected to ground at pins RFREQ and RAMP (see graphsin this data sheet for further explanation.)Output current pulses are enabled when an ‘L’ signal isapplied to the OUTEN pin. No output current flows whenOUTEN is ‘H’ and additional laser diode protection isprovided since the OUTEN input will float high when open.Complete IOUT shut-off is also achieved by holding theENABLE pin low, which will override all other control pins.The EL6173 also includes a fast-settling APC amplifierdesigned to interface directly with the front end monitordiode and the sample-and-hold amplifier for read and writepower control. Its 100MHz bandwidth and 30ns settling timeenable up to 16X CD-RW design.
