RNA51955A, B

Preliminary

R03DS0004EJ0202 Rev.2.02

Page 9 of 11

Apr 19, 2011

Power-supply

Output

Vin

RNA51955

RNA51955

Input

GND

Independent

Independent

Power-supply

Output

Input

GND

Vin

GND

Example 1. Independent power supply system

Please do enough verifying about

Example 2. Logic pulse input

(not recommended)

Figure 4

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.

+ Iin

error margin

Power-supply

Output

Vin

Iin

→

RNA51955

GND

Input

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.