LC78601E Datasheet, PDF (9/11 Pages) Sanyo Semicon Device – Compact Disc Player DSP with Built-in Microcontroller

LC78601E
Notes on Application Design
It goes without saying that applications must strictly observe the absolute maximum ratings and allowable operating
ranges (and recommended operating conditions) stipulated for this IC to achieve reliability as a system. However, we
also strongly recommend that designers carefully consider both the mounting conditions and the actual usage
environment, including ambient temperatures and static electricity, when designing applications.
This section provides additional notes concerning design, mounting, and certain other points that require care during
application design.
1. Handling of Unused Pins
If any unused pins on this IC are left in the open state, certain internal states may become undefined. Unused pins for
which the handling is specified in the documentation must be handled as specified. Also be sure that no output pins
contact any power supply or ground lines or any other output pin.
2. Latch-up Prevention
• Due to the internal structure of this IC, the same potential must be applied to all power supply pins.
— Also provide the same potential to the servo system ASP. Since the slice level control circuit is shared with this IC,
the same power supply potential must be applied. Also be sure to apply the same potential to all ASP power supply
pins.
— For products in which the power supply pins are completely isolated within the IC and special allowances apply, be
sure to follow the detailed instructions in the documentation.
• The IC may latch up if timing discrepancies appear between the rise times for different power supply pins. Design
applications so that no discrepancies appear.
• Do not raise the voltage of any input or output pin above the V_DD level, and do not lower the voltage below V_SS. This
point requires special care when power is first applied.
• Do not allow overvoltages or abnormal signal noise levels to be applied to this IC.
• In general, latch-up can be prevented by tying unused input pins to V_DD or V_SS. However, the directions for unused pin
handling in the documentation for this IC must be followed.
• Do not short the outputs.
3. Interface
When different devices are connected, incorrect operation may result if the input V_IL and V_IH and the output V_OL and
V_OH levels do not match. Insert level shifters so that the IC is not destroyed if it is connected to a device that uses a
different power-supply voltage, such as in a dual power supply system applications.
4. Load Capacitance and Output Current
• If a load with a large capacitance is connected, the wiring may fuse since such a load can result in the equivalent of an
output short for an extended period. Also, excessive charge and discharge currents can cause noise and degrade
application performance or lead to incorrect operation. Use loads of the recommended capacitance.
• Excessive output sink or source currents can lead to problems similar to those described above. Use this IC within the
recommended current levels while taking the maximum allowable power dissipation into consideration as well.
5. Notes on Power Application and Reset
• There are cases where care is required at power on, during a reset, and when the reset state is cleared. Refer to the
specifications sheet for the product and observe the notes concerning power on and IC reset.
• The pin output states, the pin I/O direction settings, and the contents of the registers are not guaranteed when power is
first applied in this IC. Items that are defined by the reset operation and when the mode is set are guaranteed after that
operation. Applications must first apply a reset to this IC after power is applied. Since pin states and register contents
that are not defined by the reset operation may change over time from the states in early versions due to long term
variations across lots, applications should not depend on these values.
No. 6020-9/11