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 EL6250C is a split supply, four channel laser diode current ampli-
fier 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 I
OUT
output, allowing the user to create multi-
level 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 I
IN
. The current
seen at this pin is then amplified to become a current source at pin I
OUT
.
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
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 I
OUT
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.
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 I
IN
pin can be biased from a cur-
rent DAC or other current source.
Connection Diagram
1
2
3
4
16
15
14
13
5
6
7
12
11
9
8
10
20
19
18
17
24
23
22
21
GND
IINR
GND
IIN2
RFREQ
IIN3
IIN4
VCC1
OE2
OE3
OE4
GND
GND
VCC2
VCC2
IOUT
IOUT
GND
RAMP
CE
EOSC
VCC2
VCC2
GND
Features
Split Supply for Blue Laser diode
capability
High-performance laser diode
driver
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
Applications
Writable optical drives
Laser diode current switching
General blue laser usage
Ordering Information
Part No
Temp. Range
Package
Outline #
EL6250CU
0C to +70C
QSOP-24
MDP0040
EL6250C - Product Brief
Split Supply Laser Driver and Oscillator
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EL6250C - Product Brief
Split Supply Laser Driver and 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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