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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Features
"Shrink-Small" Outline Package
Voltage-controlled output current
source requiring one external set
resistor per channel
Current-controlled output current
source
CH2 to 250mA max
CH3 to 150mA max
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
Auto-oscillator for read
Single +5V supply (10%)
Disable feature for power-up
protection and power savings
Fast Settling APC Amplifier
Applications
CD-RW applications
Writable optical drives
Laser diode current switching
Ordering Information
Part No
Temp. Range
Package
Outline #
EL6248CU
0C to +70C
24-Pin QSOP
MDP0040
General Description
The EL6248C is a high-performance three channel laser driver that
provides controlled current to a grounded laser diode. Channels 2 and
3 should be used as the write channels, with switching speeds of
approximately one nanosecond rise/fall time. All three 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 the I
IN
pin
(virtually ground). 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 output current
modulation when in any mode. This is turned on when the OSCEN
and OUTEN pins are held high. 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
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
shut-off is also achieved by
holding the ENABLE pin low, which will override all other control
pins.
The EL6248C also includes a fast settling APC amplifier designed to
interface directly with the front end monitor diode and the sample-
and-hold amplifier for read and write power control. Its 100MHz
bandwidth and 30ns settling time enable up to 16X CD-RW design.
1
2
3
4
16
15
14
13
5
6
7
12
11
9
8
10
20
19
18
17
24
23
22
21
VOUT
PDIN
VREF
VCC
IINR
VCC
IIN2
IOUT
RFREQ
IOUT
IIN3
GND
OUTENR
RAMP
OUTEN3
ENABLE
OUTEN2
OSCEN
GND
VCC
NC
GND
NC
NC
Connection Diagram
EL6248C - Product Brief
3-Channel Laser Diode Driver w/Oscillator & APC Amplifier
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EL6248C - Product Brief
3-Channel Laser Diode Driver w/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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