EL6279C - Product Brief
4-Ch Laser Diode Driver + Oscillator
Features
General Description
• Ultra-Small Package Outline
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 IOUT 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 IIN pin (virtually ground). The current seen at this pin is then
• 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
amplified by 100X to become a current source at pin IOUT
.
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 IOUT shutoff is also achieved by hold-
ing the ENABLE pin low, which will override the OUTEN control
pins.
• 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
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).
Applications
• CD-RW applications
• Writable optical drives
• Laser diode current switching
The external IIN 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 IIN pin can be
biased from a current DAC or other current source.
Ordering Information
Part No.
Temp. Range
Package
Outline #
EL6279CU
0°C to +70°C
QSOP-16
MDP0040
Connection Diagram
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
IINR
VCC
VCC
IIN2
RFREQ
IOUT
GND
IIN3
RAMP
IIN4
OUTEN2
ENABLE
OSCEN
VCC
OUTEN3
OUTEN4
© 1998 Élantec, Inc.