Optical Pickup Chipset with Photodetector ICs
Supports High-Speed Writing to CD and DVD
CXA2702GA/CXA2716GA/CXA2701GA
Although it has only been a year since Sony released
CXA2 7 0 2 GA/ CXA2 7 1 6 GA
the CXA2676GA and CXA2677GA* for DVD ×8-speed
RF/S e rvo P DICs
I
Supports high-speed CD/DVD write operations
(CD-R: ×52-speed, DVD-R: ×16-speed)
WPP1 (B+C) and WPP2 (A+D) outputs, which are
optimal for DVD address pit detection
Variable limiter function
CXA2702GA: Eight-division photodiode
CXA2716GA: Twelve-division photodiode
18-pin LGA COB small package
recording, DVD recording speed has already reached
×16.
Sony’s newly-developed CXA2701GA and CXA2702GA/
CXA2716GA optical pickup photodetector ICs (PDICs)
support this ×16 record speed.
I
I
I
I
*
: See CX-News, Volume 32, for details on the CXA2676GA and CXA2677GA.
CXA2 7 0 1 GA
La s e r Fro n t Mo n it o r P DIC
I
I
I
Differential output
Two-channel structure (Vin1, Vin2)
12-pin LGA COB small package
age externally so that applications can set
the limiter voltage to provide optimal
pickup performance. Note that although
the CXA2702GA includes a built-in
8-division photodiode that supports the
same differential push-pull method as the
earlier product (CXA2677GA), Sony has
also added to the product lineup the
CXA2716GA, which includes a built-in
12-division photodiode that supports the
differential astigmatism method. Both the
CXA2702GA and CXA2716GA feature
the extremely fast main output settling
time (for a 1 V amplitude) of 6 ns.
Support for Lead-Free
Mounting
CXA2702GA/CXA2716GA
The CXA2702GA is a photodetector IC
(PDIC) that was developed as the photo-
detector for optical pickups used in
DVD R/RW recording drives. Like the
earlier ×8-speed CXA2677GA, it provides
the WPP1 and WPP2 signals that are
optimal for address pit signal detection.
In increasing the recording speed to ×16,
Sony added a 3× gain switching function
to WPP1 and WPP2. The new IC thus has
an additional 2 bits of control compared
to the earlier gain switching system. The
CXA2702GA also now provides an input
pin that can control the output limiter volt-
Since the chip on board (COB) package
adopted for these ICs has excellent resis-
tance to heat, these ICs support mounting
with lead-free solder. They allow two-pass
reflow mounting with a peak temperature
of 250°C.
Note: Since the thermal resistance is strongly
influenced by the usage environment, verify the
details of the specifications in advance, or contact
your Sony representative for consultation.
CXA2701GA
Like the earlier ×8-speed CXA2676GA,
the CXA2701GA adopts a two-channel
structure to allow the CD laser and the
DVD laser power levels to be set individu-
ally. However, the output was changed to
the differential type in this new product.
This was because the output at the read
power became even smaller due to low-
ering the gain of the first stage I-V ampli-
fier (transimpedance amplifier) to 1/√2 to
support ×16-speed laser diodes. Switch-
ing to a differential amplifier improves the
signal-to-noise ratio by √2 and also allows
the common mode noise in the transmis-
sion system to be cancelled.
V
O
I
C
E
Our achievement of ×16-speed
DVD recording required pushing
our circuit technologies to the limit
to get the utmost performance
from Sony’s process technolo-
gies. The two of us on this devel-
opment team had to come up with
a lot of mutual support and en-
couragement during this design
effort. We are probably not the
only ones who are hoping that this
achievement marks the end of the
competition for ever higher
speeds.