LMH6533 Datasheet, PDF (1/11 Pages) National Semiconductor (TI) – Four - Channel Laser Diode Driver with Dual Output, LVDS Interface and HFM Oscillator

May 2004
LMH6533
Four –Channel Laser Diode Driver with Dual Output,
LVDS Interface and HFM Oscillator
General Description
The LMH™ 6533 is a laser diode driver for use in combina-
tion DVD/CD recordable and rewritable systems. The part
contains two high-current outputs for reading and writing the
DVD (650 nm) and CD (780 nm) lasers. Functionality in-
cludes read, write and erase through four separate switched
current channels. The channel currents are summed to-
gether at the selected output to generate multilevel wave-
forms for reading, writing and erasing of optical discs. The
LVDS interface delivers DVD write speeds of 12x and higher
while minimizing noise and crosstalk. The LMH6533 is opti-
mized for both speed and power consumption to meet the
demands of next generation systems. The part features a
150 mA read channel plus one 300 mA and two 150 mA write
channels, which can be summed to allow a total output
current of 500 mA or greater. The channel currents are set
through four independent current inputs.
The part is manufactured in National Semiconductor’s
VIP10™ process, which features bonded wafer technology
and trench isolation for very high switching speeds at low
power levels. An on-board High-Frequency Modulator (HFM)
oscillator helps reduce low-frequency noise of the laser and
is enabled with the ENOSC pin. The fully differential oscilla-
tor circuit minimizes supply line noise, easing FCC approval
of the overall system. The SELB pin (active HIGH) selects
the output channel and oscillator settings. External resistors
determine oscillator frequency and amplitude for each set-
ting. The write and erase channels can be switched on and
off through dedicated LVDS interface pins.
Features
n Fast switching: Rise and fall times <0.8 ns
n Low voltage differential signaling (LVDS) channels
enable interface for the fast switching lines
n Low output current noise: <0.5nA/
n Dual output: Selectable by SELB pin (active HIGH)
n Four independent current channels
— Gain of 300, 300 mA write channel
— Gain of 150, 150 mA low-noise read channel
— Two gain of 150, 150 mA write channels
— 500 mA minimum combined output current
n Integrated AC Coupled HFM Oscillator
— Selectable frequency and amplitude setting by
external resistors
— 200 MHz to 600 MHz frequency range
— Amplitude to 100 mA peak-to-peak modulation
n Complete shutdown by ENABLE pin
n 5V single-supply operation
n Logic inputs TTL and CMOS compatible
n Space saving Leadless Leadframe Package LLP^®-28
Applications
n Combination DVD/CD recordable and rewritable drives
n DVD camcorders
n DVD video recorders
Block Diagram
LMH™ is a trademark of National Semiconductor Corporation.
VIP10™ is a trademark of National Semiconductor Corporation.
LLP^® is a registered trademark of National Semiconductor.
© 2004 National Semiconductor Corporation DS200277
20027701
www.national.com