EL6173

Features:

• "Shrink-Small" outline package
• Voltage-controlled output current source to 200mA per channel, requiring one external set resistor per channel
• Current-controlled output current source to 200mA per channel
• Rise time = 0.8ns
• Fall time = 0.8ns
• On-chip oscillator with frequency and amplitude control by use of external resistors to ground
• Oscillator to 500MHz
• Oscillator to 100mAPK/PK
• Single +5V supply (±10%)
• Disable feature for power-up protection and power savings
• Fast-settling APC amplifier
• Pb-free Available as an Option



Application

• CD-RW applications
• Writable optical drives
• Laser diode current switching


Description

   The EL6173 is a high performance three-channel laser driver that provides controlled current to a grounded laser diode. Write channels 2 and 3 can provide up to 200mA per channel of DC or pulsed current, with switching speeds of approximately one nanosecond rise/fall time. All three channels are summed together at the I_OUT
output, allowing the user to create multilevel waveforms in order to optimize laser diode performance. The level of the output current is set by an analog voltage applied to an external resistor which converts the voltage into a current at the IIN pin (virtually ground). The current seen at this pin is then amplified to become a current source at pin I_OUT.

   An on-chip 500MHz oscillator EL6173 is provided to allow output current modulation when in any mode. This is turned on when the OSCEN pin is held high. Complete control of
amplitude and frequency is set by two external resistors connected to ground at pins R_FREQ and R_AMP (see graphs in this data sheet for further explanation.)

   Output current pulses EL6173 are enabled when an 'L' signal is applied to the OUTEN pin. No output current flows when OUTEN is 'H' and additional laser diode protection is
provided since the OUTEN input will float high when open. Complete I_OUT shut-off is also achieved by holding the ENABLE pin low, which will override all other control pins.

   The EL6173 also includes a fast-settling APC amplifier designed to interface directly with the front end monitor diode and the sample-and-hold amplifier for read and write power control. Its 100MHz bandwidth and 30ns settling time enable up to 16X CD-RW design.