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RTC - 4543 SA/SB
Page - 12 MQ - 252 - 03
12. Application notes
12-1. Notes on handling
This module uses a C-MOS IC to realize low power consumption. Carefully note the following cautions when
handling.
(1) Static electricity
While this module has built-in circuitry designed to protect it against electrostatic discharge, the chip
could still be damaged by a large discharge of static electricity. Containers used for packing and
transport should be constructed of conductive materials. In addition, only soldering irons, measurement
circuits, and other such devices which do not leak high voltage should be used with this module, which
should also be grounded when such devices are being used.
(2) Noise
If a signal with excessive external noise is applied to the power supply or input pins, the device may
malfunction or "latch up." In order to ensure stable operation, connect a filter capacitor (preferably
ceramic) of greater that 0.1F as close as possible to the power supply pins (between V
DD
and GNDs).
Also, avoid placing any device that generates high level of electronic noise near this module.
* Do not connect signal lines to the shaded area in the figure shown in Fig. 1 and, if possible, embed
this area in a GND land.
(3) Voltage levels of input pins
When the input pins are at the mid-level, this will cause increased current consumption and a reduced
noise margin, and can impair the functioning of the device. Therefore, try as much as possible to apply
the voltage level close to V
DD
or GND.
(4) Handling of unused pins
Since the input impedance of the input pins is extremely high, operating the device with these pins in
the open circuit state can lead to unstable voltage level and malfunctions due to noise. Therefore, pull-
up or pull-down resistors should be provided for all unused input pins.
12-2. Notes on packaging
(1) Soldering heat resistance.
If the temperature within the package exceeds 260, the characteristics of the crystal oscillator will be
degraded and it may be damaged. The reflow conditions within our reflow profile is recommended.
Therefore, always check the mounting temperature and time before mounting this device. Also, check
again if the mounting conditions are later changed.
* See Fig. 2 profile for our evaluation of Soldering heat resistance for reference.
(2) Mounting equipment
While this module can be used with general-purpose mounting equipment, the internal crystal oscillator
may be damaged in some circumstances, depending on the equipment and conditions. Therefore, be
sure to check this. In addition, if the mounting conditions are later changed, the same check should be
performed again.
(3) Ultrasonic cleaning
Depending on the usage conditions, there is a possibility that the crystal oscillator will be damaged by
resonance during ultrasonic cleaning. Since the conditions under which ultrasonic cleaning is carried
out (the type of cleaner, power level, time, state of the inside of the cleaning vessel, etc.) vary widely,
this device is not warranted against damage during ultrasonic cleaning.
(4) Mounting orientation
This device can be damaged if it is mounted in the wrong orientation. Always confirm the orientation of
the device before mounting.
(5) Leakage between pins
Leakage between pins may occur if the power is turned on while the device has condensation or dirt on
it. Make sure the device is dry and clean before supplying power to it.
Fig. 1: Example GND Pattern Fig. 2: Reference profile for our evaluation of Soldering heat resistance.
RTC - 4543 SA
( SOP-14pin )
RTC - 4543 SB
( SOP-18pin )
+1
∼
+5
°
C / s
100 s
Pre-heating area
−
1
∼
−
5
°
C / s
time [ s ]
Temperature [
°
C ]
+170
°
C +220
°
C
+260
°
C
Max.
+1
∼
+5
°
C / s
35 s
Stable Melting area