资 源 简 介
The EL6146 is a four channel laserdiode current amplifier that providescontrolled current to a grounded laserdiode. Channels 2, 3, and 4 must be used as the writechannels, with switching speeds of approximately onenanosecond rise/fall TIme. All four channels are summedtogether at the IOUT output, allowing the user to createmulTIlevel waveforms in order to opTImize laser diodeperformance. The level of the output current is set by ananalog voltage applied to an external resistor which convertsthe voltage into a current at the IIN pin (virtually ground). Thecurrent seen at this pin is then amplified to become a currentsource at pin IOUT.An on-chip 500MHz oscillator is provided to allow currentmodulaTIon when in any mode. This is turned on when theOSCEN pin is held high. Complete control of amplitude andfrequency is set by two external resistors connected toground at pins RFREQ and RAMP (see graphs in this datasheet 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 shutoff is also achieved by holding theENABLE pin low, which will override all other control pins.The external resistors allow the user to accurately andindependently set each amplifier transconductance byapplying a voltage to each resistor, without restriction on thevoltage range, thus ensuring broad voltage DACcompatibility. Alternatively, the IIN pin can be biased from acurrent DAC or other current source.
