XB1117-12 Datasheet, PDF (8/12 Pages) Torex Semiconductor – 1A Low Dropout Positive Voltage Regulator

XB1117 Series
˙OPERATIONAL EXPLANATION (Continued)
3. Thermal protection
XB1117 series has thermal protection which limits junction temperature to 150ˆ. However, device functionally is only
guaranteed to a maximum junction temperature of + 125ˆ. The power dissipation and junction temperature for the XB1117
series are given by;
PD=(VIN-VOUT) x IOUT
TJ=TA+(PDʷВJA)
NOTEɿTJ must not exceed 125ˆ.
4. Current limit protection
XB1117 series is protected against overload conditions. Current protection is triggered at 1.5A (TYP.).
5. Thermal consideration
The XB1117 series contain thermal limiting circuitry designed to protect itself from over-temperature conditions. Even for
normal load conditions, maximum junction temperature ratings must not be exceeded. As mentioned in thermal protection
section, we need to consider all sources of thermal resistance between junction and ambient. It includes junction-to-case,
case-to-heat-sink interface and heat sink thermal resistance itself.
Junction-to-case thermal resistance is specified from the IC junction to the bottom of the case directly below the die. Proper
mounting is required to ensure the best possible thermal flow from this area of the package to the heat sink. The case of all
devices in this product series is electrically connected to the output. Therefore, if the case of the device is not electrically
isolated, a thermally conductive spacer is recommended.
˙APPLICATION CIRCUITS
˔Adjustable Output Voltage
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