RT9823 RICHTEK [Richtek Technology Corporation], RT9823 Datasheet - Page 6

• Manufacturer Part Number: RT9823
• Description: Smart Multi-Voltage Detector
• Manufacturer: RICHTEK [Richtek Technology Corporation]

RT9823
Application Information
The RT9823 smart voltage detector monitors two voltage
levels at the same time to ensure that the micro processor
is operated within the recommended input voltage range.
In conventional reset IC application, to monitor one power
rail needs one reset IC. The RT9823 can monitor two power
rails simultaneously, by using just one reset IC. The
RT9823 also provides a Manual reset (MR) function for
easy application. Glitch rejection is implemented in the
RT9823 to prevent false operation and eliminate additional
de-bouncing circuitry.
Thermal Considerations
For continuous operation, do not exceed absolute
maximum junction temperature. The maximum power
dissipation depends on the thermal resistance of the IC
package, PCB layout, rate of surrounding airflow, and
difference between junction and ambient temperature. The
maximum power dissipation can be calculated by the
following formula :
P
where T
the ambient temperature, and θ
thermal resistance.
For recommended operating condition specifications of
the RT9823, the maximum junction temperature is 125°C
and T
thermal resistance, θ
23-6 packages, the thermal resistance, θ
on a standard JEDEC 51-3 single-layer thermal test board.
The maximum power dissipation at T
calculated by the following formula :
P
SOT-23-6 package
The maximum power dissipation depends on the operating
ambient temperature for fixed T
resistance, θ
curve in Figure 1 allows the designer to see the effect of
rising ambient temperature on the maximum power
dissipation.
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6
D(MAX)
D(MAX)
A
is the ambient temperature. The junction to ambient
= (T
J(MAX)
= (125°C − 25°C) / (250°C/W) = 0.4W for
J(MAX)
JA
is the maximum junction temperature, T
. For the RT9823 package, the derating
− T
A
JA
) / θ
, is layout dependent. For SOT-
JA
JA
is the junction to ambient
J (MAX)
A
= 25°C can be
JA
and thermal
, is 250°C/W
A
is
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
Figure 1. Derating Curves for RT9823 Package
0
25
Ambient Temperature (°C)
50
DS9823-02 June 2011
75
Single Layer PCB
100
125