Datasheet

Technical Note
15/18
BR25S□□□ Series
www.rohm.com
2010.12 - Rev.B
© 2010 ROHM Co., Ltd. All rights reserved.
●Noise countermeasures
○Vcc noise (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 bypass capacitor (0.1μF) between IC Vcc and GND. At that time, attach it as close to IC as
possible.
And, it is also recommended to attach a bypass capacitor between board Vcc and GND.
○SCK noise
When the rise time of SCK (tRC) is long, and a certain degree or more of noise exists, malfunction may occur owing to
clock bit displacement. To avoid this, a Schmitt trigger circuit is built in SCK input. The hysteresis width of this circuit is set
about 0.2V, if noises exist at SCK input, set the noise amplitude 0.2Vp-p or below. And it is recommended to set the rise
time of SCK (tRC) 100ns or below. In the case when the rise time is 100ns or higher, take sufficient noise
countermeasures. Make the clock rise, fall time as small as possible.
○WPB noise
During execution of write status register command, if there exist noises on WPB pin, mistake in recognition may occur
and forcible cancellation may result. To avoid this, a Schmitt trigger circuit is built in WPB input. In the same manner, a
Schmitt trigger circuit is built in CSB input, SI input and HOLDB input too.
●Notes for 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 operating 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 higher than that
of GND terminal.
(5) Heat design
In consideration of permissible dissipation in actual use condition, carry out heat design with sufficient margin.
(6) Terminal to terminal short circuit 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 short circuit 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.