For reset ICs, what are the recommended resistance values for the divider resistances R1 (ground side) and R2 (power supply side) and the capacitor CIN between VDD and ground?
Except for the BU48xx/48xx and BU42xx/43xx series, we recommend a CIN greater than 0.1uF, supply side resistance R2=15kΩ or less (100kΩ or less for the BD52xx-2C/BD53xx-2C). As a precaution for use, when R2 is large voltage drop and oscillation may occur due to the product of the through-current that occurs during reset operation. There is also the possibility of oscillation due to the effects of the power supply input waveform. Evaluate the variation operation after setting CIN under an assumed temperature range using the actual input waveform with a resistance twice the set value of R2. As a countermeasure against oscillation, increase CIN and reduce R2. For the BU48xx/49xx and BU42xx/43xx series the through-current is on the order of mA, making them unsuitable for resistance division. To use, set R2=1kΩ or less and verify variation operation.
