BU9883FV-W_1 Datasheet, PDF (17/19 Pages) Rohm – I2C BUS3Ports for HDMI Port Serial EEPROM

BU9883FV-W
Technical Note
3. Set SDA0～3 and SCL0～3 so as not to become 'Hi-Z'.
When the above conditions 1 and 2 cannot be observed, take the following countermeasures.
a) In the case when the above condition 1 cannot be observed. When SDA0～3 becomes 'L' at power on.
→Control SCL0～3 and SDA0～3 as shown below, to make SCL0～3 and SDA0～3, 'H' and 'H'.
VCC
SCL
tLOW
SDA
After Vcc becomes stable
tDH t_SU:DAT
After Vcc becomes stable
tSU:DAT
Fig.61 When SCL0～3= 'H' and SDA0～3= 'L'
Fig.62 When SCL0～3='L' and SDA0～3='L'
b) In the case when the above condition 2 cannot be observed.
→After power source becomes stable, execute software reset(P11).
c) In the case when the above conditions 1 and 2 cannot be observed.
→Carry out a), and then carry out b).
●Low voltage malfunction prevention function
LVCC circuit prevents data rewrite action at low power, and prevents wrong write. At LVCC voltage (Typ. =1.2V) or below, it
prevent data rewrite.
●VCC noise countermeasures
○Bypass capacitor
When noise or surge gets in the power source line, malfunction may occur, therefore, for removing these, it is
recommended to attach a by pass capacitor (0.1μF) between IC VCCOUT and GND. At that moment, attach it as close to IC
as possible. And, it is also recommended to attach a bypass capacitor between board VCCOUT and GND.
●Cautions on use
(1) Described numeric values and data are design representative values, and the values are not guaranteed.
(2) We believe that application circuit examples are recommendable, however, in actual use, confirm characteristics further
sufficiently. In the case of use by changing the fixed number of external parts, make your decision with sufficient margin
in consideration of static characteristics and transition characteristics and fluctuations of external parts and our LSI.
(3) Absolute maximum ratings
If the absolute maximum ratings such as impressed voltage and action temperature range and so forth are exceeded,
LSI may be destructed. Do not impress voltage and temperature exceeding the absolute maximum ratings. In the case
of fear exceeding the absolute maximum ratings, take physical safety countermeasures such as fuses, and see to it that
conditions exceeding the absolute maximum ratings should not be impressed to LSI.
(4) GND electric potential
Set the voltage of GND terminal lowest at any action condition. Make sure that each terminal voltage is lower than that of
GND terminal.
(5) Terminal design
In consideration of permissible loss in actual use condition, carry out heat design with sufficient margin.
(6) Terminal to terminal shortcircuit and wrong packaging
When to package LSI onto a board, pay sufficient attention to LSI direction and displacement. Wrong packaging may
destruct LSI. And in the case of shortcircuit between LSI terminals and terminals and power source, terminal and GND
owing to foreign matter, LSI may be destructed.
(7) Use in a strong electromagnetic field may cause malfunction, therefore, evaluate design sufficiently.
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17/18
2009.04 - Rev.B