M51955A Datasheet, PDF (8/12 Pages) Mitsubishi Electric Semiconductor – VOLTAGE DETECTING, SYSTEM RESETTING IC SERIES

M51955A,B/M51956A,B
Independent
V_CC1
V_CC2
Input
Vin
Power-supply
M51955
M51956
Output
GND
Vin
VCC
GND
V_CC
Independent
Power-supply
Input
M51955
M51956
Output
GND
Example 1. Independent power supply system
Please do enough verifying about
transition characteristic of V_CC1
and V_CC2.
Figure 4
Example 2. Logic pulse input
(not recommended)
3. Calculation of detecting voltage
Detecting voltage Vs can be calculated by the following expression.
However, the error margin is caused in the detecting voltage because input current Iin (standard 100 nA) exists if it
sets too big resistance.
Please set the constant to disregard this error margin.
V_S = 1.25 ×
R₁ + R₂
R₂
+ Iin × R₁
error margin
V_CC
R₁
Iin
Vin
→
Input
Power-supply
M51955
M51956
Output
R₂
GND
Figure 5 Influence of Input Current
4. About the voltage input outside ratings
Please do not input the voltage outside ratings to the input terminal.
An internal protection diode becomes order bias, and a large current flows.
REJ03D0777-0200 Rev.2.00 Aug 20, 2007
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