LC78601E Datasheet, PDF (10/11 Pages) Sanyo Semicon Device – Compact Disc Player DSP with Built-in Microcontroller

LC78601E
6. Notes on Thermal Design
The failure rate of semiconductor devices is accelerated by higher ambient temperatures and power dissipation levels.
We strongly recommend taking changes in ambient conditions into account and providing as large a margin as
possible in thermal design to assure high reliability.
7. Notes on Printed Circuit Board Pattern Design
• Ideally, the influence of shared impedances should be minimized by separating the V_DD and ground lines for each
system.
• Design V_DD and ground lines to be as short and as wide as possible, and to have the lowest high-frequency impedance
possible. Ideally, decoupling capacitors (0.01 to 1 µF) should be inserted in each V_DD/ground pair. These capacitor
should be placed as close to the corresponding V_DD pin as possible. It is also appropriate to insert capacitors of about
100 to 220 µF between each V_DD and ground as low-frequency filters. However, be careful not to use values that are
too large for these capacitors, since that can result in latch-up.
— In the servo system, the reference voltage line (V_REF) and the driver V_CC and ground lines are handled in the same
way. The driver ground line should be made especially wide. If at all possible, use the recommended driver pattern,
which, being directly under the device, was also designed to provide a heat dissipation effect as well.
— If a current output pickup is used, locate the optical pickup element connector and the ASP RF input as close
together as possible. Even if a voltage output type pickup is used, the I/V conversion resistor located at the ASP
input should be located near the ASP RF input.
• The EFM signal line should be made as short as possible, and should either be located away from adjacent lines or
should be shielded from adjacent lines by V_SS or V_DD shield lines.
Since the slice level control output (EFMO) can easily disrupt the EFM signal line, the resistor connected to the output
pin should be located as close to the pin as possible. Note that reducing the value of this resistor increases the influence
of spurious radiation and cares must be taken for the output level when the value increases.
• Cover the area around the crystal with the ground pattern.
8. Other Notes
If you have any questions during the application design phase, do not hesitate to contact your Sanyo sales
representative or the nearest Sanyo semiconductor sales office.
This IC is specifically designed for use in CD players, and as such its specifications differ from those of general-
purpose product standard logic ICs. We recommend system debugging using the end product system itself and
adopting failsafe system design if required by the application.
No. 6020-10/11