300mA CMOS L.D.O. Regulator
EQUATION 2-2:
LM1108
Table 2-1 shows various values of
θJA
for the LM1108 versus board copper area.
TABLE 2-1 : THERMAL RESISTANCE GUIDELINES FOR LM1108
Equation 2-1can be used in conjunction with Equation 2-2 to ensure regulator thermal operation is within limits.
For example:
In this example, the LM1108 dissipates a maximum of 260mW; below the allow able limit of 508 mW. In a
similar manner, Equation 2-1 and Equation 2-2 can be used to calculate maximum current and/or input voltage
limits. For example, the maximum allowable V
IN
, is found by sustituting the maximum allowable power
dissipation of 508 mW into Equation 2-1, from which V
INMAX
= 4.6V.
HTC
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HTC [ HTC KOREA TAEJIN TECHNOLOGY CO. ]
