EL6247C - Product Brief
EL6247C - Product Brief
3-Ch Laser Diode Driver + Oscillator
Features
• “Shrink-Small” Outline Package
• Voltage output current source
requiring one external set resistor
per channel
• Auto Oscillator On-Off with
OUTEN Signals
• 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
• Single +5V supply (±10%)
• Current amplification = 100
• Disable feature for power-up
protection and power savings
• CMOS control signals
General Description
The EL6247C is a three channel laser diode current amplifier that pro-
vides controlled current to a grounded laser diode. Channels 2 and 3
should be used as the write channels, with switching speeds of approxi-
mately one nanosecond rise/fall time. All three channels are summed
together at the I
OUT
output, allowing the user to create multilevel wave-
forms 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 cur-
rent 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 500MHz oscillator is provided to allow output current mod-
ulation when in read mode. The oscillator is enabled when the OSCEN
pin is held high. If any of channels 2 or 3 are active, the oscillator is
switched off. 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 external I
IN
resistors allow the user to accurately and independently
set each amplifier transconductance by applying a voltage to each resis-
tor, 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.
Applications
• CD-RW applications
• Writable optical drives
• Laser diode current switching
Ordering Information
Part No.
EL6247CU
Temp. Range
0°C to +70°C
Package
QSOP-16
Outline #
MDP0040
Connection Diagram
1 IINR
2 IIN2
3 GND
4 RFREQ
5 IIN3
6 OUTENR
7 OUTEN2
8 OUTEN3
VCC 16
VCC 15
IOUT 14
GND 13
October 25, 2001
RAMP 12
ENABLE 11
OSCEN 10
VCC 9
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.
ELANTEC [ ELANTEC SEMICONDUCTOR ]
