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.
2001 Elantec Semiconductor, Inc.
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General Description
The EL6249C is a four channel laser diode current amplifier that pro-
vides controlled current to a grounded laser diode. Channels 2, 3, and 4
should be used as the write channels, with switching speeds of approxi-
mately one nanosecond rise/fall time. All four channels are summed
together at the I
OUT
output, allowing the user to create multilevel wave-
forms 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). The current seen at this pin is then amplified to become a cur-
rent source at pin I
OUT
.
Output current pulses are enabled when an `L' signal is applied to the
OUTEN pin. No output current flows when OUTEN is `H' and addi-
tional laser diode protection is provided since the OUTEN input will
float high when open. Complete I
OUT
shutoff is also achieved by hold-
ing the ENABLE pin low, which will override the OUTEN control pins.
An on-chip 500MHz oscillator is provided to allow output current mod-
ulation 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 I
IN
resistors allow the user to accurately and independently
set each amplifier transconductance by applying a voltage to each resis-
tor, without restriction on the voltage range, thus ensuring broad
voltage DAC compatibility. Alternatively, the I
IN
pin can be biased
from a current DAC or other current source.
Connection Diagram
1
2
3
4
16
15
14
13
5
6
7
12
11
10
8
9
IINR
OUTEN4
IIN2
RFREQ
IIN3
IIN4
OUTEN2
OUTEN3
VCC
VCC
OSCEN
ENABLE
RAMP
GND
IOUT
VCC
Features
"Shrink-Small" Outline Package
Voltage controlled 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
Applications
CD-RW applications
Writable optical drives
Laser diode current switching
Ordering Information
Part No.
Temp. Range
Package
Outline #
EL6249CU
0C to +70C
16-Pin QSOP
MDP0040
EL6249C - Product Brief
4-Ch Laser Diode Driver + Oscillator
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EL6249C - Product Brief
4-Ch Laser Diode Driver + Oscillator
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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 cir-
cuitry 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.
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 sup-
port 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 con-
templating 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. Elan-
tec, Inc.'s warranty is limited to replacement of defective
components and does not cover injury to persons or property or
other consequential damages.
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Printed in U.S.A.
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
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