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參數(shù)資料
| 型號(hào)： | AAT3239ITS-1.85-T1 |
| 廠商： | Advanced Analog Technology,lnc. |
| 英文描述： | 500mA MicroPower LDO |
| 中文描述： | 500mA的微功率LDO |
| 文件頁數(shù)： | 11/14頁 |
| 文件大?。?/td> | 290K |
| 代理商： | AAT3239ITS-1.85-T1 |
AAT3239
500mA MicroPower LDO
3239.2006.03.1.2
11
diode. Conditions where V
OUT
might exceed V
IN
should be avoided since this would forward bias
the internal parasitic diode and allow excessive
current flow into the V
OUT
pin, possibly damaging
the LDO regulator.
In applications where there is a possibility of V
OUT
exceeding V
IN
for brief amounts of time during nor-
mal operation, the use of a larger value C
IN
capaci-
tor is highly recommended. A larger value of C
IN
with respect to C
OUT
will effect a slower C
IN
decay
rate during shutdown, thus preventing V
OUT
from
exceeding V
IN
. In applications where there is a
greater danger of V
OUT
exceeding V
IN
for extended
periods of time, it is recommended to place a
Schottky diode across V
IN
to V
OUT
(connecting the
cathode to V
IN
and anode to V
OUT
). The Schottky
diode forward voltage should be less than 0.45 volts.
Thermal Considerations and High
Output Current Applications
The AAT3239 is designed to deliver a continuous
output load current of 500mA under normal opera-
tions. The short-circuit current limit is greater than
500mA, typically active at 600mA.
The limiting characteristics for the maximum output
load current safe operating area is essentially pack-
age power dissipation, the internal preset thermal
limit of the device, and the input-to-output voltage
drop across the AAT3239. In order to obtain high
operating currents, careful device layout and circuit
operating conditions need to be taken into account.
The following discussions will assume the LDO reg-
ulator is mounted on a printed circuit board utilizing
the minimum recommended footprint as stated in
the layout considerations section of this document.
At any given ambient temperature (T
A
), the maxi-
mum package power dissipation can be determined
by the following equation:
Constants for the AAT3239 are T
J(MAX)
, the maxi-
mum junction temperature for the device which is
125°C, and T
JA
= 90°C/W, the package thermal
resistance. Typically, maximum conditions are calcu-
lated at the maximum operating temperature of T
A
=
85°C and under normal ambient conditions where
T
A
= 25°C. Given T
A
= 85°C, the maximum package
power dissipation is 444mW. At T
A
= 25°C, the max-
imum package power dissipation is 1.11W.
The maximum continuous output current for the
AAT3239 is a function of the package power dissi-
pation and the input-to-output voltage drop across
the LDO regulator. Refer to the following simple
equation:
For example, if V
IN
= 4.2V, V
OUT
= 1.8V, and T
A
=
25°C, I
OUT(MAX)
< 463mA. If the output load current
were to exceed 463mA or if the ambient tempera-
ture were to increase, the internal die temperature
would increase. If the condition remained constant,
the LDO regulator thermal protection circuit would
activate.
To determine the maximum output current for a
given output voltage, refer to the following equa-
tion. This calculation accounts for the total power
dissipation of the LDO regulator, including that
caused by ground current.
This formula can be solved for I
OUT
to determine the
maximum output current.
I
OUT
= P
D(MAX)
- (V
IN
×
I
GND
)
V
IN
- V
OUT
P
D(MAX)
= (V
IN
- V
OUT
)I
OUT
+ (V
IN
x I
GND
)
I
OUT(MAX)
<
P
D(MAX)
V
IN
- V
OUT
P
D(MAX)
= T
J(MAX)
- T
A
JA
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AAT3239ITS-1.8-T1 | 500mA MicroPower LDO |
| AAT3239ITS-2.5-T1 | 500mA MicroPower LDO |
| AAT3239ITS-3.3-T1 | 500mA MicroPower LDO |
| AAT3242ITP-IN-T1 | 300mA/150mA Dual CMOS LDO Linear Regulator |
| AAT3242ITP-IP-T1 | 300mA/150mA Dual CMOS LDO Linear Regulator |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AAT3239ITS-2.5-T1 | 制造商:ANALOGICTECH 制造商全稱:Advanced Analogic Technologies 功能描述:500mA MicroPower LDO |
| AAT3239ITS-3.3-T1 | 制造商:ANALOGICTECH 制造商全稱:Advanced Analogic Technologies 功能描述:500mA MicroPower LDO |
| AAT3242 | 制造商:ANALOGICTECH 制造商全稱:Advanced Analogic Technologies 功能描述:300mA/150mA Dual CMOS LDO Linear Regulator |
| AAT3242_08 | 制造商:ANALOGICTECH 制造商全稱:Advanced Analogic Technologies 功能描述:300mA/150mA Dual CMOS LDO Linear Regulator |
| AAT3242ITP-IG-T1 | 制造商:ANALOGICTECH 制造商全稱:Advanced Analogic Technologies 功能描述:300mA/150mA Dual CMOS LDO Linear Regulator |
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