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參數(shù)資料
| 型號： | AAT3239ITS-1.5-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)： | 10/14頁 |
| 文件大?。?/td> | 290K |
| 代理商： | AAT3239ITS-1.5-T1 |
AAT3239
500mA MicroPower LDO
10
3239.2006.03.1.2
Equivalent Series Resistance:
ESR is a very
important characteristic to consider when selecting
a capacitor. ESR is the internal series resistance
associated with a capacitor that includes lead
resistance, internal connections, size and area,
material composition, and ambient temperature.
Typically, capacitor ESR is measured in milliohms
for ceramic capacitors and can range to more than
several ohms for tantalum or aluminum electrolytic
capacitors.
Ceramic Capacitor Materials:
tors less than 0.1μF are typically made from NPO
or C0G materials. NPO and C0G materials gener-
ally have tight tolerance and are very stable over
temperature. Larger capacitor values are usually
composed of X7R, X5R, Z5U, or Y5V dielectric
materials. These two material types are not rec-
ommended for use with LDO regulators since the
capacitor tolerance can vary more than ±50% over
the operating temperature range of the device. A
2.2μF Y5V capacitor could be reduced to 1μF over
temperature; this could cause problems for circuit
operation. X7R and X5R dielectrics are much
more desirable. The temperature tolerance of X7R
dielectric is better than ±15%.
Ceramic capaci-
Capacitor area is another contributor to ESR.
Capacitors that are physically large in size will have
a lower ESR when compared to a smaller sized
capacitor of an equivalent material and capacitance
value. These larger devices can improve circuit tran-
sient response when compared to an equal value
capacitor in a smaller package size.
Consult capacitor vendor datasheets carefully
when selecting capacitors for LDO regulators.
Enable Function
The AAT3239 features an LDO regulator enable/
disable function. This pin (EN) is active high and is
compatible with CMOS logic. To assure the LDO
regulator will switch on, the EN turn-on control level
must be greater than 1.5V. The LDO regulator will
go into the disable shutdown mode when the volt-
age on the EN pin falls below 0.6V. If the enable
function is not needed in a specific application, it
may be tied to V
IN
to keep the LDO regulator in a
continuously on state.
When the LDO regulator is in shutdown mode, an
internal 1.5k
resistor is connected between V
OUT
and GND. This is intended to discharge C
OUT
when
the LDO regulator is disabled. The internal 1.5k
has no adverse effect on device turn-on time.
Short-Circuit Protection
The AAT3239 contains an internal short-circuit pro-
tection circuit that will trigger when the output load
current exceeds the internal threshold limit. Under
short-circuit conditions, the output of the LDO reg-
ulator will be current limited until the short-circuit
condition is removed from the output or LDO regu-
lator package power dissipation exceeds the
device thermal limit.
Thermal Protection
The AAT3239 has an internal thermal protection cir-
cuit which will turn on when the device die temper-
ature exceeds 145°C. The internal thermal protec-
tion circuit will actively turn off the LDO regulator
output pass device to prevent the possibility of over-
temperature damage. The LDO regulator output
will remain in a shutdown state until the internal die
temperature falls back below the 145°C trip point.
The combination and interaction between the short-
circuit and thermal protection systems allow the
LDO regulator to withstand indefinite short-circuit
conditions without sustaining permanent damage.
No-Load Stability
The AAT3239 is designed to maintain output volt-
age regulation and stability under operational no-
load conditions. This is an important characteristic
for applications where the output current may drop
to zero.
Reverse Output-to-Input Voltage
Conditions and Protection
Under normal operating conditions, a parasitic
diode exists between the output and input of the
LDO regulator. The input voltage should always
remain greater than the output load voltage main-
taining a reverse bias on the internal parasitic
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PDF描述 |
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| 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 |
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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