NCP346SN1T1G ON Semiconductor, NCP346SN1T1G Datasheet - Page 8

• Manufacturer Part Number: NCP346SN1T1G
• Description: Supervisory Circuits 4.45V Overvoltage Supervisor
• Manufacturer: ON Semiconductor

Specifications of NCP346SN1T1G

• Number Of Voltages Monitored: 1
• Monitored Voltage: 4.45 V
• Overvoltage Threshold: Adjustable, 4.55 V
• Output Type: PFET Driver
• Manual Reset: Resettable
• Watchdog: No Watchdog
• Supply Voltage (max): 25 V
• Supply Voltage (min): 2.5 V
• Supply Current (typ): 650 uA
• Maximum Power Dissipation: 216 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SOT-23-5 Thin (TSOP-5)
• Minimum Operating Temperature: - 40 C
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Design Steps for Adjusting the Overvoltage Threshold
1. Use Typical R
2. Minimize R
3. Let X = R
4. Identify Required Nominal Overvoltage Threshold.
5. Calculate nominal R
6. Pick Standard Resistor Values as Close as Possible to
7. Use min/max Data and Resistor Tolerances to
V OVmin + V thmin (1 ) R 1min R 2max ) R 1min R inmax )
V OVmax + V thmax (1 ) R 1min R 2max ) R 1max R inmin )
V OVtyp + V thtyp (1 ) R 1typ R 2typ ) R 1typ R intyp )
Specifications
these Values
Determine Overvoltage Detection Tolerance:
V OV + V th (1 ) R 1 R 2 ) R 1 R in ).
R 1 + R in X
in
in
/ R
R 2 +
Effect by Selecting R
in
1
, and V
= 100.
(V OV V th * R 1 R in * 1)
1
and R
th
Values from the Electrical
2
R 1
from Nominal Values:
1
<< R
in
since:
(eq. 10)
(eq. 11)
http://onsemi.com
(eq. 6)
(eq. 7)
(eq. 8)
(eq. 9)
NCP346
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comparator, so the minimum input threshold voltage (V
is the falling voltage detection point and the maximum is the
rising voltage detection point. One should design the input
supply such that its maximum supply voltage in normal
operation is less than the minimum desired overvoltage
threshold.
8. Use worst case resistor tolerances to determine the
This is shown empirically in Tables 2 through 4.
detection voltage from the NCP346SN2T2, which has a
typical V
V(V CC , IN) min + V CCmax * (R1min (R1min ) R2max))
V(V CC , IN)typ + V CCmax * (R1typ (R1typ ) R2typ)) (eq. 13)
V(V CC , IN) max + V CCmax * (R1max (R1max ) R2min))
The specification takes into account the hysteresis of the
The following tables show an example of obtaining a 6 V
maximum V(V
th
of 5.5 V.
CC
,IN)
(eq. 12)
(eq. 14)
th
)