Split Supply Laser Driver and Oscillator
General Description
• Split Supply for Blue Laser diode
• High-performance laser diode
• Voltage-controlled output current
source to 150mA per channel,
requiring one external set resistor
per channel
• Current-controlled output current
source to 150mA per channel
• Rise time = 2.0ns
• Fall time = 2.0ns
• 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
The EL6250C is a split supply, four channel laser diode current amplifier that provides controlled current to a grounded laser diode. Channels
2, 3, and 4 must be used as the write channels, with switching speeds of
approximately two nanoseconds 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 pin IIN. The current
seen at this pin is then amplified to become a current source at pin IOUT.
An on-chip 500MHz 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
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. VCC2 should be set to
about 1.5V above the maximum laser voltage, while VCC1 should be set
to +5V to minimize chip dissipation.
• Writable optical drives
• Laser diode current switching
• General blue laser usage
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
Connection Diagram
Part No
Temp. Range
0°C to +70°C
Outline #
GND 24
VCC2 23
VCC2 22
4 IIN2
GND 19
7 IIN4
CE 17
9 OE2
10 OE3
VCC2 15
11 OE4
VCC2 14
12 GND
GND 13
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
6 IIN3
8 VCC1
© 2001 Elantec Semiconductor, Inc.
EL6250C - Product Brief
EL6250C - Product Brief
EL6250C - Product Brief
EL6250C - Product Brief
Split Supply Laser Driver and 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
(408) 945-9305
European Office: +44-118-977-6020
Japan Technical Center: +81-45-682-5820
Printed in U.S.A.