max5084attt Maxim Integrated Products, Inc., max5084attt Datasheet - Page 8

• Manufacturer Part Number: max5084attt
• Description: 65v, 200ma, Low-quiescent-current Linear Regulators In Tdfn
• Manufacturer: Maxim Integrated Products, Inc.

Use Figure 3 to determine the allowable package dissi-
pation for a given ambient temperature. Alternately, use
the following formula to calculate the allowable pack-
age dissipation:
After determining the allowable package dissipation,
calculate the maximum output current using the follow-
ing formula:
The above equations do not include the negligible
power dissipation from self-heating due to the device’s
ground current.
Example 1:
T
V
V
65V, 200mA, Low-Quiescent-Current
Linear Regulators in TDFN
Figure 2. Adjustable Output Voltage Operation
8
P
A
IN
OUT
V
D
IN
TO 65V
= +85°C
=
= 6.5V
_______________________________________________________________________________________
= 14V
10μF
⎧
⎨
⎩
= 5V
1 905
1 905
.
.
I
W for T
W
OUT(MAX)
– .
0 0238
IN
EN
GND
A
≤ +
W C x T
MAX5084
MAX5085
/
°
70
=
OUT_SENSE
°
C
(
V
IN
A
OUT
SET
−
70
– V
P
°
D
C for
)
OUT
+
10μF
70
≤ 2 0 0 m A
°
C
<
V
OUT
R1
R2
T
A
= 2.5V TO 11V
(200mA)
≤ +
125
LOAD
°
C
⎫
⎬
⎭
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
V
V
Calculate package dissipation at the given temperature
as follows:
And establish the maximum output current:
Example 3:
T
V
V
Figure 3. Calculated Maximum Power Dissipation vs.
Temperature
A
P
A
IN
OUT
IN
OUT
P
D
D
= +125°C
= +50°C
= 14V
= 9V
= 1.905W – 0.0238W/°C (125°C – 70°C) = 596mW
= 1.905W – 0.0238W/°C (85°C – 70°C) = 1.548W
= 3.3V
= 5V
I
OUT MAX
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
I OUT MAX
0
-40
(
(
-20
MAXIMUM POWER
1.905W
)
)
=
0
=
14
TEMPERATURE (°C)
20
14
596
1 548
V
.
40
V
−
mW
DERATE
23.8mW/°C
3 3
−
60
.
W
5
V
V
80 100 120 140
=
=
172
56
mA
mA