AAT3215IGV-2.8-T1 AAT [Advanced Analog Technology, Inc.], AAT3215IGV-2.8-T1 Datasheet - Page 12

• Manufacturer Part Number: AAT3215IGV-2.8-T1
• Description: 150mA CMOS High Performance LDO
• Manufacturer: AAT [Advanced Analog Technology, Inc.]

Thus, the AAT3215 can sustain a constant 2.5V out-
put at a 150mA load current as long as V
at an ambient temperature of 25°C. 6.0V is the
absolute maximum voltage where an AAT3215
would never be operated, thus at 25°C, the device
would not have any thermal concerns or operational
V
This situation can be different at 85°C. The follow-
ing is an example for an AAT3215 set for a 2.5V
output at 85°C:
V
I
I
V
From the discussion above, P
mined to equal 211mW at T
Higher input-to-output voltage differentials can be
obtained with the AAT3215, while maintaining device
functions within 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:
I
I
V
V
P
12
%DC = 100
%DC = 100
%DC = 85.54%
OUT
GND
V
GND
OUT
IN(MAX)
OUT
IN(MAX)
IN
IN
OUT
D(MAX)
IN(MAX)
is greater than 3.90V, which is the maximum
= 150µA
= 150mA
= 4.2V
= 2.5V
OUT
was assumed to be 211mW.
limits.
=
= 2.5V
= 150mA
= 150µA
= 3.90V
211mW + (2.5V
= 2.5V at a 150mA load and T
A
(4.2V - 2.5V)150mA + (4.2V · 150μA)
(V
= 85°C. To maintain this high input
150mA + 150μA
IN
- V
OUT
)I
P
OUT
D(MAX)
·
A
150mA)
+ (V
211mW
= 85°C.
IN
D(MAX)
· I
OUT
GND
IN
)
was deter-
= 2.5V at
is ≤ 6.00V
IN
A
= 85°C.
= 4.2V
150mA CMOS High Performance LDO
For a 150mA output current and a 2.7V drop
across the AAT3215 at an ambient temperature of
85°C, the maximum on-time duty cycle for the
device would be 85.54%.
The following family of curves show the safe oper-
ating area for duty-cycled operation from ambient
room temperature to the maximum operating level.
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
3
2
3
2
0
1
0
1
0
1
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
(V
30
30
200mA
OUT
OUT
OUT
Duty Cycle (%)
Duty Cycle (%)
Duty Cycle (%)
40
40
40
= 2.5V @ 25°C)
= 2.5V @ 85°C)
= 2.5V @ 50°C)
50
50
50
150mA
60
60
60
200mA
AAT3215
70
70
70
200mA
DROP
DROP
DROP
3215.2006.05.1.6
80
80
80
150mA
100mA
90
90
90
100
100
100