EL6211

Features:

• "Shrink-Small" outline package
• Voltage-controlled output current source requiring one external set resistor per channel
• Current-controlled output current source
• Rise time = 1.6ns
• Fall time = 1.9ns
• On chip oscillator with frequency and amplitude control by use of external resistors to ground
• Oscillator to 500MHz
• Oscillator to 100mA_PK/PK
• Single +5V supply (±10%)
• Disable feature for power-up protection and power savings
• CMOS control signals



Application

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


Description

   The EL6211 is a three-channel laser diode current amplifier that provides controlled current to a grounded laser diode. Channels 2 and 3 should be used as the write
channels, with switching speeds of less than two nanoseconds rise/fall time. All three channels are summed together at the IOUT 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 I_IN pin (virtually ground).

   An on-chip 500MHz oscillator EL6211 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 EL6211 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 shutoff is also achieved by holding the ENABLE pin low, which will override the OUTEN control
pins.

   The external resistors EL6211 allow the user to accurately and independently set each amplifier transconductance by applying a voltage to each resistor, without restriction on the voltage range, thus ensuring broad voltage DAC compatibility. Alternatively, the IIN pin can be biased from a current DAC or other current source.