1998 lantec, Inc.
EL
6279C -
Produ
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B
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General Description
The EL6279C is a four channel laser diode current amplifier that pro-
vides controlled current to a grounded laser diode. The four amplifiers
can provide up to 100 mA per channel of DC or pulsed current. Chan-
nels 2, 3, and 4 should be used as the write channels, with switching
speeds of approximately three nanosecond rise/fall time. All four
channels are summed together at the I
OUT
output, allowing the user to
create multilevel waveforms in order to optimize laser diode perfor-
mance. 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 by 100X to become a current 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 500 MHz oscillator is provided to allow output current
modulation 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 fre-
quency 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 indepen-
dently 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 current DAC or other current source.
Connection Diagram
VCC
VCC
IOUT
IIN3
RAMP
GND
OUTEN2
ENABLE
VCC
IIN4
OUTEN3
OUTEN4
IIN2
RFREQ
IINR
OSCEN
1
2
3
4
16
15
14
13
5
6
7
12
11
10
8
9
Features
Ultra-Small Package Outline
Current-controlled output current
source to 100 mA per channel,
requiring one external set resistor
per channel
Auto Oscillator On-Off with
OUTEN Signals
Rise time = 3.0 ns
Fall time = 3.5 ns
On chip oscillator with frequency
and amplitude control by use of
external resistors to ground
Oscillator to 500 MHz
Oscillator to 100 mA 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 #
EL6279CU
0C to +70C
QSOP-16
MDP0040
EL6279C - Product Brief
4-Ch Laser Diode Driver + Oscillator
February 22, 2000
2
EL6279C - Product Brief
4-Ch Laser Diode Driver + Oscillator
E
L
6279C - Pr
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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.
lantec, Inc.
675 Trade Zone Blvd.
Milpitas, CA 95035
Telephone: (408) 945-1323
(888) LANTEC
Fax:
(408) 945-9305
European Office: +44-118-977-6080
February 22, 2000
Printed in U.S.A.
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