Low Noise 4-Channel Laser Diode Driver + Oscillator Features General Description • Low output noise = 4.0nA/rt-Hz • High-performance laser diode driver • Pin compatible with EL6257 • Voltage-controlled output current source to 150 mA per channel, requiring one external set resistor per channel • Current-controlled output current source to 150 mA per channel • Rise time = 1.0 ns • Fall time = 1.1 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%) • Disable feature for power-up protection and power savings • TTL/CMOS control signals The EL6259C is a low noise four channel laser diode current amplifier that provides controlled current to a grounded laser diode. The four amplifiers can provide up to 150 mA per channel of DC or pulsed current. Channels 2, 3, and 4 must be used as the write channels, with switching speeds of approximately one 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. The current seen at this pin is then amplified by 100X to become a current source at pin IOUT. Applications • • • • DVD-RAM high speed drives CD-RW applications Writable optical drives Laser diode current switching EL6259C - Product Brief EL6259C - Product Brief An on-chip 500 MHz oscillator is provided to allow current modulation when in the read mode. This is turned on when the EOSC pin is held high (floating not recommended). 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). Output current pulses are enabled when an ‘L’ signal is applied to the OE pin. No output current flows when OE is ‘H’, and additional laser diode protection is provided since the OE input will float high when open. Complete IOUT shut-off is also achieved by holding the CE pin low, which will override the OE control pins. The external 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. Ordering Information Part No Temp. Range Package Outline # EL6259CU 0°C to +70°C QSOP-24 MDP0040 North America: 1-888-352-6832 X 311 Asia: +85-45-682-5820 Europe: +44-18-977-6020 ©2000 Elantec Semiconductor, Inc. GND IINR 1 24 2 23 GND IIN2 3 22 4 21 RFREQ IIN3 IIN4 5 20 6 19 7 18 IOUT GND RAMP OER OE2 OE3 OE4 8 17 CE 9 16 10 15 11 14 EOSC VCC VCC 12 13 GND GND VCC VCC IOUT GND January 31, 2000 Complete Product Specifications Elantec Technical Support: Connection Diagram EL6259C - Product EL6259C - Product Brief Low Noise 4-Channel Laser Diode Driver + Oscillator General Disclaimer Specifications contained in this product brief are in effect as of the publication date shown. Elantec Semiconductor, Inc. reserves the right to make changes in the circuitry or specifications contained herein at any time without notice. Elantec Semiconductor, Inc. assumes no responsibility for the use of any circuits described herein and makes no representations that they are free from patent infringement. January 31, 2000 WARNING - Life Support Policy Elantec Semiconductor, Inc. products are not authorized for and should not be used within Life Support Systems without the specific written consent of Elantec Semiconductor, 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 Semiconductor, Inc. Products in Life Support Systems are requested to contact Elantec Semiconductor, Inc. factory headquarters to establish suitable terms & conditions for these applications. Elantec Semiconductor, 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) 352-6832 (toll free) Fax: (408) 945-9305 European Office: 44-18-977-6020 Japan Office: 85-45-682-5820 2 Printed in U.S.A.