AS1364
Datasheet - Detailed Description
Current Limiter
The AS1364 features current limiting circuitry that monitors the pass transistor, limiting short-circuit output current to
1.5A (typ). The circuitry of the AS1364 allows that the output can be shorted to ground for an indefinite period of time
without damaging the device.
Internal P-Channel Pass Transistor
The AS1364 features a 1A P-channel MOSFET pass transistor and consumes only a maximum of 200µA of quiescent
current under heavy loads as well as in dropout.
Thermal Protection
Integrated thermal overload protection limits the total power dissipation in the AS1364. When the junction temperature
(TJ) exceeds +170ºC typically, the pass transistor is turned off. Normal operation is continued when TJ drops approxi-
mately 20ºC.
Note: Regardless of the hysteresis, continuous short-circuit condition will result in a pulsed output.
Operating Region and Power Dissipation
Maximum power dissipation of the AS1364 depends on the thermal resistance of the package and the PCB, the tem-
perature difference between the die junction and ambient air, and the rate of air flow.
The power dissipated in the device is given as:
PD = IOUT × (VIN – VOUT
)
(EQ 3)
(EQ 4)
The maximum power dissipation is calculated:
T
J(MAX) – TAMB
---------------------------------------
PDMAX =
θ
JC + θJA
Where:
TJ(MAX) - TAMB is the temperature difference between the device die junction and the surrounding air.
θJC is the thermal resistance of the junction to the case.
θJA is the thermal resistance from the case through the PCB, copper traces, and other materials to the surrounding air.
Connect the exposed thermal pad and GND to circuit ground by using a large pad, or multiple vias to the ground plane.
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