Example 1:
T
A
= +95°C
V
IN
= +14V
V
OUT
= +5V
Find the maximum allowable output current. First calcu-
late package dissipation at the given temperature as
follows:
Then determine the maximum output current:
Example 2:
T
A
= +125°C
V
IN
= +14V
V
OUT
= +3.3V
Calculate package dissipation at the given temperature
as follows:
And establish the maximum current:
Example 3:
T
A
= +50°C
V
IN
= +14V
V
OUT
= +5V
Calculate package dissipation at the given temperature
as follows:
P
D
= 1.538W
And find the maximum output current:
In Example 3, the maximum output current is calculated
as 170.9mA, however, the maximum output current
cannot exceed 150mA. Use Figure 6 to quickly deter-
mine allowable maximum output current for selected
ambient temperatures.
Capacitor Selection and Regulator
Stability
For stable operation over the full temperature range
and with load currents up to 150mA, use a 15µF (min)
output capacitor with an ESR < 0.5Ω. To reduce noise
and improve load-transient response, stability, and
power-supply rejection, use larger output capacitor val-
ues such as 22µF.
Some ceramic dielectrics exhibit large capacitance
and ESR variation with temperature. For dielectric
capacitors such as Z5U and Y5V, use 22µF or more to
ensure stability at temperatures below -10°C. With X7R
or X5R dielectrics, 15µF should be sufficient at all oper-
ating temperatures. For high-ESR tantalum capacitors
use 22µF or more to maintain stability. To improve
power-supply rejection and transient response use a
minimum 10µF capacitor between IN and GND.
