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.

6
2
5
5
C

-

P

r
o
d

u
c
t

B

r
i
e
f

General Description

The EL6255C is a high-performance four channel laser diode current
amplifier that provides controlled current to a grounded laser diode.
The four amplifiers can provide up to 150 mA per channel of DC or
pulsed current. Channels 2, 3, and 4 must be used as the write chan-
nels, with switching speeds of one 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

pin (virtually ground). The current seen at this pin is then

amplified by 100X to become a current source at pin I

OUT

An on-chip 500 MHz oscillator is provided to allow current modula-
tion 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 any of the
OUTEN pins for channels 2, 3, and 4 (the write channels) are low (see
truth table).

Output current pulses are enabled when an `L' signal is applied to the
OUTEN pins. 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 the OUTEN con-
trol pins.

Connection Diagram

Features

· Shrink-small package outline
· Voltage-controlled output current

source to 150 mA per channel,

requiring one external set resistor

per channel

· Current-controlled output current

source to 150 mA per channel

· Rise time = 1.0 ns
· Fall time = 1.1 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

· TTL/CMOS control signals

Applications

· DVD drives
· CD-RW applications
· Writable optical drives
· Laser diode current switching

Ordering Information

Part No

Temp. Range

Package

Outline #

EL6255CU

0°C to +70°C

QSOP-16

MDP0040

EL6255C - Product Brief

4-Channel Laser Diode Driver + Oscillator

J
u

l
y

3
0
,

1
9
9
9

VCC

IOUT

IIN3

RAMP

GND

OUTEN2

ENABLE

VCC

IIN4

OUTEN3

OUTEN4

IIN2

RFREQ

IINR

OSCEN

EL6255C - Product Brief

4-Channel Laser Diode Driver + Oscillator

6
2
5
5
C

-

P

r
o
d
u

c
t

B

r
i
e
f

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.

J
u
l
y

3
0
,

1
9
9
9

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

Part Number EL6255C