SE5117FSG datasheet(4/6 Pages) ESTEK

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Application Hints

Thermal Consideration

SE5117

Like any Low dropout regulator, SE5117 requires

external capacitors to ensure stability. The external

capacitors must be carefully selected to ensure the

performances.

Input Capacitor:

An Input Capacitor of at least 10uF is required.

Ceramic or Tantalum can be used. The value can

be increased without upper limit.

It is important that the thermal limit of the package

should not be exceeded. The SE5117 has built-in

thermal protection. When the thermal limit is

exceeded, the IC will enter protection, and the VOUT

will be reset to zero. The power dissipation for a

given application can be calculated as follows:

The Power Dissipation (PD) is

PD = IOUT * [VIN –VOUT]

Output Capacitor:

An Output Capacitor is required for look stability. It

must be located no more than 1cm away from the

VOUT pin, and connected directly between VOUT and

GND pins. The minimum value is 10uF but once

again its value can be increased without limit.

The thermal limit of the package is then limited to

PD(MAX) = [TJ –TA]/θJA where TJ is the junction

temperature, TA is ambient temperature, and θJA is

around 135°C/W for SE5117. SE5117 is designed

to enter thermal protection at 150°C. For example, if

TA is 25°C then the max PD is limited to about 1W. In

other words, if IOUT(MAX) = 1A, then [VIN –VOUT] can

not exceed 1V.

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