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 EL6258C is a high-performance three channel laser diode current
amplifier that provides controlled current to a grounded laser diode.
Channels 2 and 3 must be used as the write channels, with switching
speeds of approximately one nanosecond rise/fall time. All three chan-
nels are summed together at the I
OUT
output, allowing the user to
create multilevel waveforms. Each level of output current is set by an
analog voltage applied to an external resistor which converts the volt-
age into a current at the I
IN
pins (virtually ground). The current seen at
these pins is then amplified by 100X (150X on CH3) to become a cur-
rent source at pin I
OUT
.
An on-chip 500MHz oscillator is provided to allow current modula-
tion when in the read mode. This is turned on when the OSCEN 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 for further explanation). The
oscillator will also turn off whenever either of the OUTEN pins for
channels 2 or 3 (the write channels) are low (see truth table).
Output current pulses are enabled when an `L' signal is applied to the
OUTEN pins. 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
shut-off is also achieved by
holding the ENABLE pin low, which will override the OUTEN con-
trol pins.
The EL6258C also includes a fast settling APC amplifier designed to
interface directly with the power monitor photodiode and the sample-
and-hold amplifier, for read and write power control.
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
IIN2
GND
RFREQ
IIN3
OUTENR
OUTEN2
OUTEN3
GND
VREF
VOUT
GND
VCC
VCC
IOUT
IOUT
GND
RAMP
ENABLE
OSCEN
VCC
GND
PDIN
Features
High-performance laser diode
driver
Voltage-controlled output current
source requiring one external set
resistor per channel
Current-controlled output current
source
Rise time = 1.0ns
Fall time = 1.1ns
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
TTL/CMOS control signals
Fast settling APC amplifier
Applications
DVD drives
CD-RW applications
Writable optical drives
Laser diode current switching
Ordering Information
Part No
Temp. Range
Package
Outline #
EL6258CU
0C to +70C
QSOP-24
MDP0040
EL6258C - Product Brief
3-Channel Laser Driver + Oscillator + APC Amplifier
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EL6258C - Product Brief
3-Channel Laser Driver + Oscillator + APC Amplifier
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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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