MB3771
■ APPLICATION CIRCUIT
1. 5V Power Supply Monitor
Monitored by VSA. Detection threshold voltage is VSAL and VSAH
VCC
MB3771
1
2
3
4
8
7
6
5
RESET
Logic
circuit
CT
2. 5V Power Supply Voltage Monitor (Externally Fine-Tuned Type)
The VSA detection voltage can be adjusted externally.
Resistance R1 and R2 are set sufficiently lower than the IC internal partial voltage resistance, so that the detection
voltage can be set using the ratio between resistance R1 and R2. (See the table below).
• R1, R2 calculation formula (when R1 << 100 kΩ, R2 <<40 kΩ)
VSAL =: (R1 + R2 ) × VSB /R2 [V], VSAH =: (R1 + R2 ) × (VSB + VHYSB)/ R2 [V]
R1 (kΩ)
10
R2 (kΩ)
3.9
Detection voltage : VSAL (V) Detection voltage : VSAH (V)
4.37
4.11
4.47
4.20
9.1
3.9
V
CC
MB3771
1
2
8
7
RESET
R
1
2
Logic
Circuit
CT
3
4
6
5
R
7
FUJITSU [ FUJITSU ]
