Elantec EL6277CU 3-channel laser diode driver oscillator Datasheet

3-Channel Laser Diode Driver + Oscillator
Features
General Description
• Ultra-Small Package Outline
• High-performance laser diode
driver
• Current-controlled output current
source, 100 mA channel R and 2,
200mA channel 3, requiring one
external set resistor per channel
• Rise time = 3.0 ns
• Fall time = 3.5ns
• 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
• TTL/CMOS control signals
The EL6277C is a high-performance three channel laser diode current
driver that provides controlled current to a grounded laser diode.
Channel R and 2 can provide 100mA per channel of DC or pulsed current, while channel 3 can provide 200mA per channel. Channels 2, and
3 must be used as the write channels, with switching speeds of approximately three nanosecond rise/fall time. All three channels are
summed together at the IOUT output, allowing the user to create multilevel 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 IIN pin
(near ground). The current seen at this pin is then amplified by 100X
to become a current source at pin IOUT.
Application
• CD-RW applications
• Writable optical drives
• Laser diode current switching
Ordering Information
Part No
Temp. Range
Package
Outline #
EL6277CU
0°C to +70°C
QSOP-16
MDP0041
EL6277C - Product
EL6277C - Product Brief
An on-chip 500 MHz oscillator is provided to allow current modulation 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 in this data sheet 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 a ‘Low’ signal is applied to
the OUTEN pin. No output current flows when OUTEN is ‘H’, and
additional laser diode protection is provided since the OUTEN input
will float high when open. Complete IOUT shut-off is also achieved by
holding the ENABLE pin low, which will override the OUTEN control pins.
The external resistors allow the user to accurately and independently
set each amplifier trans conductance by applying a voltage to each
resistor, without restriction on the voltage range. Alternatively, the IIN
pin can be biased from a current DAC or other current source.
Connection Diagram
1
16
IIN2
GND
RFREQ
IIN3
OUTENR
OUTEN2
OUTEN3
2
15
3
14
4
13
5
12
6
11
7
10
8
9
VCC
VCC
IOUT
GND
RAMP
ENABLE
OSCEN
VCC
February 22, 2000
© 1997 Elantec, Inc.
IINR
EL6277C - Product
EL6277C - Product Brief
3-Channel Laser Diode Driver + Oscillator
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 circuitry 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.
February 22, 2000
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 support 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 contemplating 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. Elantec, Inc.’s warranty is limited to replacement of defective
components and does not cover injury to persons or property or
other consequential damages.
Elantec, Inc.
675 Trade Zone Blvd.
Milpitas, CA 95035
Telephone: (408) 945-1323
(888) 352-6832 (toll free)
Fax:
(408) 945-9305
European Office: 44-18-977-6020
2
Printed in U.S.A.
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