4-Ch Laser Diode Driver + Oscillator Features General Description • Ultra-Small Package Outline • Current-controlled output current source to 100 mA per channel, requiring one external set resistor per channel • Auto Oscillator On-Off with OUTEN Signals • Rise time = 3.0 ns • Fall time = 3.5 ns • On chip oscillator with frequency and amplitude control by use of external resistors to ground • Oscillator to 500 MHz • Oscillator to 100 mA pk/pk • Single +5V supply (±10%) • Current amplification = 100 • Disable feature for power-up protection and power savings • CMOS control signals The EL6279C is a four channel laser diode current amplifier that provides controlled current to a grounded laser diode. The four amplifiers can provide up to 100 mA per channel of DC or pulsed current. Channels 2, 3, and 4 should be used as the write channels, with switching speeds of approximately three nanosecond rise/fall time. All four 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 IIN pin (virtually ground). The current seen at this pin is then amplified by 100X to become a current source at pin IOUT. Applications • CD-RW applications • Writable optical drives • Laser diode current switching Ordering Information Part No. Temp. Range Package Outline # EL6279CU 0°C to +70°C QSOP-16 MDP0040 EL6279C - Product Brief EL6279C - Product Brief Output current pulses 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 IOUT shutoff is also achieved by holding the ENABLE pin low, which will override the OUTEN control pins. An on-chip 500 MHz oscillator is provided to allow output current modulation when in read mode. The oscillator is enabled when the OSCEN pin is held high. If any of channels 2, 3, or 4 are active, the oscillator is switched off. Complete control of amplitude and frequency is set by two external resistors connected to ground at pins RFREQ and RAMP (see graphs in this data sheet for further explanation). The external IIN resistors 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. Connection Diagram 1 16 VCC IIN2 RFREQ 2 15 VCC 3 14 IIN3 4 13 IOUT GND IIN4 OUTEN2 5 12 RAMP 6 11 OUTEN3 7 10 OUTEN4 8 9 ENABLE OSCEN VCC February 22, 2000 © 1998 Élantec, Inc. IINR EL6279C - Product Brief EL6279C - Product Brief 4-Ch Laser Diode Driver + Oscillator General Disclaimer Specifications contained in this data sheet are in effect as of the publication date shown. Elantec, Inc. reserves the right to make changes in the circuitry or specifications contained herein at any time without notice. Elantec, Inc. assumes no responsibility for the use of any circuits described herein and makes no representations that they are free from patent infringement. February 22, 2000 WARNING - Life Support Policy Elantec, Inc. products are not authorized for and should not be used within Life Support Systems without the specific written consent of Elantec, Inc. Life Support systems are equipment intended to support or sustain life and whose failure to perform when properly used in accordance with instructions provided can be reasonably expected to result in significant personal injury or death. Users contemplating application of Elantec, Inc. Products in Life Support Systems are requested to contact Elantec, Inc. factory headquarters to establish suitable terms & conditions for these applications. Elantec, Inc.’s warranty is limited to replacement of defective components and does not cover injury to persons or property or other consequential damages. Élantec, Inc. 675 Trade Zone Blvd. Milpitas, CA 95035 Telephone: (408) 945-1323 (888) ÉLANTEC Fax: (408) 945-9305 European Office: +44-118-977-6080 2 Printed in U.S.A.