DATASHEET EL6204 FN7219 Rev 3.00 Laser Driver Oscillator October 28, 2015 The EL6204 is a push-pull oscillator used to reduce laser noise. Features It uses the standard interface to existing ROM controllers. The Low power dissipation frequency and amplitude are each set with a separate resistor connected to ground. The tiny package and harmonic User-selectable frequency from 60MHz to 600MHz reduction allow the part to be placed close to a laser with low controlled with a single resistor RF emissions. An auto turn-off feature allows it to easily be User-specified amplitude from 10mA to 100mA P-P P-P used on combo CD-RW plus DVD-ROM pickups. controlled with a single resistor If the APC current is reduced such that the average laser Auto turn-off threshold voltage drops to less than 1.1V, the output and oscillator are Soft edges for reduced EMI disabled, reducing power consumption to a minimum. Small 6 Ld SOT-23 package The current drawn by the oscillator consists of a small utility current, plus the peak output amplitude in the positive cycle. In Applications the negative cycle the oscillator subtracts peak output DVD players amplitude from the laser APC current. DVD-ROM drives The EL6204 part is available in the space-saving 6 Ld SOT-23 package and is specified for operation from 0C to +70C. CD-RW drives MO drives General purpose laser noise reduction Local oscillators I 1 DRIVER OSCILLATOR 6 R OUT FREQ V 2 5 GND2 DD REFERENCE AND GND1 3 AUTO SHUT-OFF BIAS 4 R AMP FIGURE 1. BLOCK DIAGRAM FN7219 Rev 3.00 Page 1 of 12 October 28, 2015EL6204 TYPICAL GAIN EMI ROM LASER SETTING REDUCTION DRIVER RESISTOR FILTERS IAPC BEAD FREQUENCY SETTING RESISTOR PNP RFREQ 1 6 IOUT RFREQ 0.1F BEAD 2 VDD GND2 5 LASER +5V DIODE RAMP 3 GND1 RAMP 4 CONTROLLER 4.7F 0.1F 0.1F GND RF AMPLITUDE BLOCKING SETTING RESISTOR PHOTO DIODE RESISTOR MAIN BOARD FLEX ON PICKUP ~10mW LASER OUTPUT POWER LASER OUTPUT POWER THRESHOLD CURRENT IAPC 0mW 0mA ~60mA LASER CURRENT OSCILLATOR CURRENT FIGURE 2. TYPICAL APPLICATION CIRCUIT FN7219 Rev 3.00 Page 2 of 12 October 28, 2015