Voltage Detector ICs
FAQ
How much pull-up resistance should be set?
The recommended value of the resistance is as follows.
| BD45□□□ |
50k to 1MΩ |
| BD47□□ |
2k to 1MΩ |
| BD47□□ |
10k to 1MΩ |
| BD52□□ |
50k to 1MΩ |
| BU42□□ |
50k to 1MΩ
100k to 1MΩ |
（VDET=1.5 to 4.8V）
(VDET=0.9 to 1.4V) (※VDET= detection voltage) |
| BU48□□ |
50k to 1MΩ
100k to 1MΩ |
(VDET=1.5 to 4.8V)
(VDET=0.9 to 1.4V) |
Those values depend on layout of board. Please confirm actual behavior of the IC before using it
How much CT pin external capacity can we set?
In BU42□□, BU43□□, BD52□□, BD53□□ the recommended value of the capacitor is 100pF to 0.1μF. Those values depend on layout of circuit board. Please confirm actual behavior of the IC before using it.
What's the role of ER pin of BD45□□G, BD46□□G.
ER pin is input for forced reset. ER pin voltage over High threshold makes output Low.
Please refer to the timing chart on technical note.
Can we put a resistor between power supply and VDD pin?
In case of application inputting resistor divided voltage to power supply pin of IC (VDD pin), penetration current can flows when output is changing and can cause malfunction such as oscillation.
(penetrate current is the current flowing from VDD to GND instantaneously when output goes H ←→ L.)
When using with resistor to VDD pin (including dividing resistor), please consider using BD48□□, BD52□□.
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Voltage Detector IC
Data Sheets