ELANT EL6279CU Datasheet

EL6279C - Product Brief

4-Ch Laser Diode Driver + Oscillator

EL6279C - Product Brief

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 MH z

• Oscillator to 100 mA pk / pk

• Single +5V supply (±10%)

• Current amplif ic a tio n = 10 0

• 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 0°C to +70°C QSOP-16 MDP0040

General Description

The EL6279C is a four channe l las er diod e current am plif ier that pro­vides controlled current to a grounded laser diode. The four amplifiers
can provide up to 100 mA pe r ch an ne l of D C or puls e d cu r re nt. Chan­nels 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
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 (virtually grou nd). Th e current seen at this pin is then
amplified by 100X to become a current source at pin I

Output current pulses ar e enabl ed whe n an ‘L’ 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 I

OUT

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 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

resistors allow the user to accurately and indepen-

IN

dently set each amplifier transcond uctance by a pplying a vo ltage to
each resistor, without restriction on the voltage range, thus ensuring
broad voltage DAC compatibility. Alternatively, the I
biased from a current DAC or other current source.

output, allowing the user to

OUT

.

OUT

shutoff is also achi eved by hold -

pin can be

IN

© 1998 Élantec, Inc.

Connection Diagram

IINR

IIN2

RFREQ

IIN3

IIN4

OUTEN2
OUTEN3

OUTEN4

1

2

3

4

5

6

7

8 9

16

15

14

13

12

11

10

VCC
VCC
IOUT

GND
RAMP
ENABLE
OSCEN
VCC

February 22, 2000

EL6279C - Product Brief

4-Ch Laser Diode Driver + Oscillator

EL6279C - Product Brief

General Disclaimer

Specifications contained in this data sheet are in effect as of the publicat ion date shown. Elantec, Inc. re serves the r ight to make changes in th e cir­cuitry or specifications cont ained herein at a ny time without notice. Elante c, Inc. assumes no res ponsibili ty for t he us e 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 intend ed to sup-

Élantec, Inc.

675 Trade Zone Blvd.
Milpitas, CA 95035
Telephone: [phone]

(888) ÉLANTEC
Fax: [phone]
European Office: [phone]

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 con­templating applicatio n of Elantec, In c. Products in Li fe 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 cov er injury to per sons or prop erty or
other consequential damages.

February 22, 2000

2

Printed in U.S.A.