3-Ch Laser Diode Driver + Oscillator Features General Description • “Shrink-Small” Outline Package • Voltage output current source requiring one external set resistor per channel • Auto Oscillator On-Off with OUTEN Signals • 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 100mA pk/pk • Single +5V supply (±10%) • Current amplification = 100 • Disable feature for power-up protection and power savings • CMOS control signals The EL6247C 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 approximately one nanosecond 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 IIN pin (virtually ground). The current seen at this pin is then amplified 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 # EL6247CU 0°C to +70°C QSOP-16 MDP0040 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 500MHz 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 or 3 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 IINR VCC 16 2 IIN2 VCC 15 3 GND IOUT 14 4 RFREQ GND 13 RAMP 12 6 OUTENR ENABLE 11 7 OUTEN2 OSCEN 10 8 OUTEN3 VCC 9 Note: All information contained in this data sheet has been carefully checked and is believed to be accurate as of the date of publication; however, this data sheet cannot be a “controlled document”. Current revisions, if any, to these specifications are maintained at the factory and are available upon your request. We recommend checking the revision level before finalization of your design documentation. October 25, 2001 5 IIN3 © 2001 Elantec Semiconductor, Inc. EL6247C - Product Brief EL6247C - Product Brief EL6247C - Product Brief EL6247C - Product Brief 3-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. October 25, 2001 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. Elantec Semiconductor, Inc. 675 Trade Zone Blvd. Milpitas, CA 95035 Telephone: (408) 945-1323 (888) ELANTEC Fax: (408) 945-9305 European Office: +44-118-977-6020 Japan Technical Center: +81-45-682-5820 2 Printed in U.S.A.