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Rev.3.3 Nov.11, 2019

AX6607

Thermal Considerations

The AX6607 series can deliver a current of up to 600mA over the full operating junction

temperature range. However, the maximum output current must be dated at higher ambient

temperature to ensure the junction temperature does not exceed 125°C. With all possible

conditions, the junction temperature must be within the range specified under operating

conditions. Power dissipation can be calculated based on the output current and the voltage

drop across regulator.

PD = (VIN - VOUT) IOUT

The final operating junction temperature for any set of conditions can be estimated by

the following thermal equation:

PD (MAX) = (TJ (MAX) - TA) / θJA

Where TJ (MAX) is the maximum junction temperature of the die (125°C) and TA is the

maximum ambient temperature. The junction to ambient thermal resistance (θJA) for

TDFN-6L package at recommended minimum footprint is 120°C/W.

PCB Layout

An input capacitance of ≅ 1μF is required between the AX6607 input pin and ground

(the amount of the capacitance may be increased without limit), this capacitor must be

located a distance of not more than 1cm from the input and return to a clean analog ground.

Input capacitor can filter out the input voltage spike caused by the surge current due to the

inductive effect of the package pin and the printed circuit board’s routing wire. Otherwise, the

actual voltage at the VIN pin may exceed the absolute maximum rating. The output capacitor

also must be located a distance of not more than 1cm from output to a clean analog ground.

Because it can filter out the output spike caused by the surge current due to the inductive

effect of the package pin and the printed circuit board’s routing wire.