MC7900 Series
P
D(max)
for T
A
= +50°C
70
60
50
40
R
qJA
30
0
5.0
10
15
20
L, LENGTH OF COPPER (mm)
Free Air
Mounted
Vertically
3.0
2.0 oz. Copper
L
Minimum
Size Pad
L
2.5
2.0
1.5
1.0
30
PD, MAXIMUM POWER DISSIPATION (W)
80
R
θ
JA, THERMAL RESISTANCE
JUNCTION-TO-AIR (
°
C/W)
3.5
Figure 11. D
2
PAK Thermal Resistance and Maximum
Power Dissipation versus P.C.B. Copper Length
DEFINITIONS
Line Regulation
− The change in output voltage for a
change in the input voltage. The measurement is made under
conditions of low dissipation or by using pulse techniques
such that the average chip temperature is not significantly
affected.
Load Regulation
− The change in output voltage for a
change in load current at constant chip temperature.
Maximum Power Dissipation
− The maximum total
device dissipation for which the regulator will operate
within specifications.
Input Bias Current
− That part of the input current that
is not delivered to the load.
Output Noise Voltage
− The rms AC voltage at the
output, with constant load and no input ripple, measured
over a specified frequency range.
Long Term Stability
− Output voltage stability under
accelerated life test conditions with the maximum rated
voltage listed in the devices’ electrical characteristics and
maximum power dissipation.
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