Application Hints
Thermal Consideration
Like any Low dropout regulator, SE5167 requires It is important that the thermal limit of the package
external capacitors to ensure stability. The external should not be exceeded. The SE5167 has built-in
capacitors must be carefully selected to ensure the thermal protection. When the thermal limit is
performances.
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:
Input Capacitor:
An Input Capacitor of at least 2.2uF is required. The
inexpensive Electrolytic capacitor is preferred. The The Power Dissipation (PD) is
value can be increased without upper limit.
PD = IOUT * [VIN – VOUT]
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
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 around 250°C/W for SE5167. SE5167 is designed
GND pins. The inexpensive Electrolytic capacitor is to enter thermal protection at 150°C. For example, if
recommended. The minimum value is 2.2uF but TA is 25°C then the max PD is limited to about 0.5W.
once again its value can be increased without limit.
In other words, if IOUT(MAX) = 300mA, then [VIN
OUT] can not exceed 1.67V.
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V
Revision 12/5/2008
Preliminary and all contents are subject to change without prior notice.
© Seaward Electronics, Inc., 2006. • www.seawardinc.com.cn • Page 6
SEAWARD [ Seaward Electronics Inc. ]
