aat3220iqy-3.5-t1 Advanced Analogic Technologies, Inc., aat3220iqy-3.5-t1 Datasheet - Page 12

• Manufacturer Part Number: aat3220iqy-3.5-t1
• Description: Aat3220 | 150ma Nanopower Ldo Linear Regulator
• Manufacturer: Advanced Analogic Technologies, Inc.

From the discussion above, P
mined to equal 200mW at T
Higher input-to-output voltage differentials can be
obtained with the AAT3220 while maintaining
device functions in the thermal safe operating area.
To accomplish this, the device thermal resistance
must be reduced by increasing the heat sink area
or by operating the LDO regulator in a duty-cycled
mode.
For example, an application requires V
while V
V
safe continuous input level for V
150mA for T
voltage and output current level, the LDO regulator
must be operated in a duty-cycled mode. Refer to
the following calculation for duty-cycle operation:
P
For a 150mA output current and a 2.0V drop across
the AAT3220 at an ambient temperature of 85°C,
the maximum on-time duty cycle for the device
would be 66.67%.
The following family of curves shows the safe oper-
ating area for duty-cycled operation from ambient
room temperature to the maximum operating level.
12
%DC = 100
%DC = 100
I
I
V
V
%DC = 66.67%
GND
OUT
IN
D(MAX)
IN
OUT
is greater than 4.33V, which is the maximum
= 1.1µA
= 150mA
= 5.0V
= 3.0V
OUT
is assumed to be 200mW
= 3.0V at a 150mA load and T
A
(5.0V - 3.0V)150mA + (5.0V × 1.1µA)
(V
= 85°C. To maintain this high input
IN
- V
OUT
)I
P
OUT
D(MAX)
A
+ (V
200mW
= 85°C.
IN
D(MAX)
× I
OUT
GND
was deter-
)
= 3.0V at
IN
A
= 85°C.
= 5.0V
150mA NanoPower™ LDO Linear Regulator
3.5
2.5
1.5
0.5
3.5
2.5
1.5
0.5
3.5
2.5
1.5
0.5
3
2
1
0
3
2
1
0
3
2
1
0
0
0
0
10
10
10
Device Duty Cycle vs. V
Device Duty Cycle vs. V
Device Duty Cycle vs. V
20
20
20
(V
(V
30
30
30
(V
OUT
OUT
OUT
200mA
Duty Cycle (%)
Duty Cycle (%)
Duty Cycle (%)
= 2.5V @ 25°C)
40
40
40
= 2.5V @ 85°C)
= 2.5V @ 50°C)
200mA
50
50
50
60
60
60
150mA
200mA
AAT3220
70
70
70
150mA
DROP
DROP
DROP
3220.2006.01.1.4
80
80
80
150mA
100mA
90
90
90
100
100
100