Collection of Product FAQs
Author: Hamaguchi Masanao
<Information level>
A:
Index:
<Product>
Division name: 01 IC
Category 1:
Category 2:
Cal No.:
Related Documents:
11 Power Supply
1. Voltage Detectors
S-807
Public (Printing O.K.)
B: Technical
Date: 98/11/12 (Thursday) 10:17 (Modified: 98/12/14 (Monday) 16:42)
Question:
What is the method for calculating delay-time of the power-on clear circuit?
Answer:
The delay time (power-on clear time) produced in a power-on clear circuit using the S-807xxAN can be
found by substituting constants in the following formula:
Vdet +
Tdelay = 1 × C × R × Ln (1 -
)
Vdd
Tdelay: Delay time [sec]
C: External capacitance value [F]
R: Resistance value [Ω]
V det+: S-807xxAN Series release voltage [V]
Vdd: Supply voltage [V]
Vdd
V
Supply voltage (Vdd)
R
Pull-up resistor
S-807xxAN release voltage (Vdet+)
S-807xxAN
S-807 input voltage
C
Delay time
Note: Set R to less than 7.5 kΩ to prevent oscillation.
40
SII [ SEIKO INSTRUMENTS INC ]
