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參數(shù)資料
| 型號： | AAT3236IJS-25-T1 |
| 廠商： | Advanced Analogic Technologies, Inc. |
| 英文描述： | 300mA CMOS High Performance LDO |
| 中文描述： | 300mA的LDO穩(wěn)壓器的CMOS高性能 |
| 文件頁數(shù)： | 10/16頁 |
| 文件大?。?/td> | 448K |
| 代理商： | AAT3236IJS-25-T1 |
periods of time, it is recommended to place a schot-
tky diode across V
IN
to V
OUT
(connecting the cath-
ode 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 AAT3236 is designed to deliver a continuous
output load current of 300mA under normal opera-
tions and can supply up to 500mA during circuit
start up conditions. This is desirable for circuit
applications where there might be a brief high in
rush current during a power on event.
The limiting characteristic for the maximum output
load current safe operating area is essentially
package power dissipation and the internal preset
thermal limit of the device. 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 the document.
At any given ambient temperature (T
A
) the maxi-
mum package power dissipation can be deter-
mined by the following equation:
P
D(MAX)
= [T
J(MAX)
- T
A
] /
Θ
JA
Constants for the AAT3236 are T
J(MAX)
, the maxi-
mum junction temperature for the device which is
125°C and
Θ
JA
= 190°C/W, the package thermal
resistance. Typically, maximum conditions are cal-
culated at the maximum operating temperature
where T
A
= 85°C, under normal ambient conditions
T
A
= 25°C. Given T
A
= 85°, the maximum package
power dissipation is 211mW. At T
A
= 25°C, the
maximum package power dissipation is 526mW
The maximum continuous output current for the
AAT3236 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:
I
OUT(MAX)
< P
D(MAX)
/ (V
IN
- V
OUT
)
For example, if V
IN
= 4.2V, V
OUT
= 3.3V and T
A
=
25°, I
OUT(MAX)
< 584mA. If the output load current
were to exceed 584mA or if the ambient tempera-
ture were to increase, the internal die temperature
will increase. If the condition remained constant,
the LDO regulator thermal protection circuit will
activate.
To figure what the maximum input voltage would be
for a given load current, refer to the following equa-
tion. This calculation accounts for the total power
dissipation of the LDO Regulator, including that
caused by ground current.
P
D(MAX)
= (V
IN
- V
OUT
)I
OUT
+ (V
IN
x I
GND
)
This formula can be solved for V
IN
to determine the
maximum input voltage.
V
IN(MAX)
= (P
D(MAX)
+ (V
OUT
x I
OUT
)) / (I
OUT
+ I
GND
)
The following is an example for an AAT3236 set for
a 3.0 volt output:
From the discussion above, P
D(MAX)
was deter-
mined to equal 526mW at T
A
= 25°C°.
V
OUT
= 3.0 volts
I
OUT
= 500mA
I
GND
= 150uA
V
IN(MAX)
=(526mW+(3.0Vx500mA))/(500mA +150μA)
V
IN(MAX)
= 4.05V
Thus, the AAT3236 can sustain a constant 3V out-
put at a 500mA load current as long as V
IN
is
≤
4.05V at an ambient temperature of 25°C.
Higher input to output voltage differentials can be
obtained with the AAT3236, while maintaining
device functions within the thermal safe operating
area. To accomplish this, the device thermal resist-
ance 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
IN
= 4.2V
while V
OUT
= 3.0V at a 500mA load and T
A
= 25°C.
V
IN
is greater then 4.05V, which is the maximum
safe continuous input level for V
OUT
= 3.0V at
500mA for T
A
= 25°C. To maintain this high input
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
D(MAX)
is assumed to be 526mW
I
GND
= 150μA
I
OUT
= 500mA
AAT3236
300mA CMOS High Performance LDO
10
3236.2001.11.0.9
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AAT3236 | Quadruple 2-Input Positive-AND Gates 14-SSOP 0 to 70 |
| AAT3236IGV-25-T1 | Quadruple 2-Input Positive-AND Gates 14-SSOP 0 to 70 |
| AAT3236IGV-28-T1 | 300mA CMOS High Performance LDO |
| AAT3236IGV-285-T1 | Quadruple 2-Input Positive-AND Gates 14-SOIC 0 to 70 |
| AAT3236IGV-30-T1 | Quadruple 2-Input Positive-AND Gates 14-SOIC 0 to 70 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AAT3236IJS-27-T1 | 制造商:ANALOGICTECH 制造商全稱:Advanced Analogic Technologies 功能描述:300mA CMOS High Performance LDO |
| AAT3236IJS-285-T1 | 制造商:ANALOGICTECH 制造商全稱:Advanced Analogic Technologies 功能描述:300mA CMOS High Performance LDO |
| AAT3236IJS-28-T1 | 制造商:ANALOGICTECH 制造商全稱:Advanced Analogic Technologies 功能描述:300mA CMOS High Performance LDO |
| AAT3236IJS-3.0-T1 | 制造商:ANALOGICTECH 制造商全稱:Advanced Analogic Technologies 功能描述:300mA CMOS High Performance LDO |
| AAT3236IJS-3.1-T1 | 制造商:AAT 制造商全稱:AAT 功能描述:300mA CMOS High Performance LDO |
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