APPENDIX C MOUNTING PRECAUTIONS
AP-C-2
Seiko Epson Corporation
S1C17M12/M13 TECHNICAL MANUAL
(Rev. 1.2)
Signal line location
• To prevent electromagnetically-induced noise arising from mutual induc-
tion, large-current signal lines should not be positioned close to pins sus-
ceptible to noise, such as oscillator and analog measurement pins.
• Locating signal lines in parallel over significant distances or crossing
signal lines operating at high speed will cause malfunctions due to noise
generated by mutual interference.
Handling of light (for bare chip mounting)
The characteristics of semiconductor components can vary when exposed to light. ICs may malfunction or non-
volatile memory data may be corrupted if ICs are exposed to light.
Consider the following precautions for circuit boards and products in which this IC is mounted to prevent IC
malfunctions attributable to light exposure.
(1) Design and mount the product so that the IC is shielded from light during use.
(2) Shield the IC from light during inspection processes.
(3) Shield the IC on the upper, underside, and side faces of the IC chip.
(4) Mount the IC chip within one week of opening the package. If the IC chip must be stored before mounting,
take measures to ensure light shielding.
(5) Adequate evaluations are required to assess nonvolatile memory data retention characteristics before prod-
uct delivery if the product is subjected to heat stress exceeding regular reflow conditions during mounting
processes.
Unused pins
(1) I/O port (P) pins
Unused pins should be left open. The control registers should be fixed at the initial status.
(2) OSC3, OSC4, and EXOSC pins
If the OSC3 crystal/ceramic oscillator circuit or EXOSC input circuit is not used, the pin should be config-
ured as a general-purpose I/O port. The control registers should be fixed at the initial status (disabled).
(3) SEG
x
, and COM
x
pins
If the seven-segment LED controller is not used, these pins should be configured as a general-purpose I/O
port. The control registers should be fixed at the initial status (display off). The unused SEG
x
and COM
x
pins that are not required to connect should be configured as a general-purpose I/O port even if the seven-
segment LED controller is used.
Miscellaneous
Minor variations over time may result in electrical damage arising from disturbances in the form of voltages
exceeding the absolute maximum rating when mounting the product in addition to physical damage. The fol-
lowing factors can give rise to these variations:
(1) Electromagnetically-induced noise from industrial power supplies used in mounting reflow, reworking after
mounting, and individual characteristic evaluation (testing) processes
(2) Electromagnetically-induced noise from a solder iron when soldering
In particular, during soldering, take care to ensure that the soldering iron GND (tip potential) has the same po-
tential as the IC GND.
OSC3
OSC4
Large current signal line
High-speed signal line
Prohibited pattern