參數(shù)資料
型號(hào): AP1084K33
英文描述: 5A Low Dropout Positive Adjustable or Fixed-Mode Regulator
中文描述: 第5A低壓差正可調(diào)或固定模式穩(wěn)壓器
文件頁(yè)數(shù): 4/10頁(yè)
文件大?。?/td> 197K
代理商: AP1084K33
5A Low Dropout Positive Adjustable or Fixed-Mode Regulator
Functional Description
Introduction
The AP1084 adjustable Low Dropout (LDO)
regulator is a 3 terminal device that can easily be
programmed with the addition of two external
resistors to any voltages within the range of 1.25 to
5V. The AP1084 only needs 1.4V differential
between Vin and Vout to maintain output regulation.
In addition, the output voltage tolerances are also
extremely tight and they include the transient
response as part of the specification. For example,
Intel VRE specification calls for a total of +/- 100mV
including initial tolerance, load regulation and 0 to
5.0A load step.
AP1084
Anachip Corp.
www.anachip.com.tw
Rev.1.0 Aug.27, 2004
4/10
The AP1084 is specifically designed to meet the
fast current transient needs as well as providing an
accurate initial voltage, reducing the overall system
cost with the need for fewer output capacitors.
Output Voltage Setting
The AP1084 can be programmed to any voltages in
the range of 1.25V to 5V with the addition of R1 and
R2 external resistors according to the following
formula:
Vout = Vref (1+ R2/R1) +Iadj *R2 , where Vref = 1.25 typically, Iadj = 55uA
typically R1&R2 as shown at below
AP1084
Adj
Vin
Vout
Vref
R1
R2
Iadj=55uA
The AP1084 keeps a constant 1.25V between the
output pin and the adjust pin. By placing a resistor
R1 across these two pins a constant current flows
through R1, adding to the
Iadj
current and into the
R2 resistor producing a voltage equal to the
(1.25/R1)*R2+Iadj*R2 which will be added to the
1.25V to set the output voltage. This is summarized
in the above equation. Since the minimum load
current requirement of the AP1084 is 10mA, R1 is
typically selected to be 121
resistor so that it
automatically
satisfies
requirement. Notice that since Iadj is typically in the
range of 55uA it only adds a small error to the
output voltage and should only be considered when
a very precise output voltage setting is required. For
example, in a typical 3.3V application where
R1=121
and R2=200
the error due to
Iadj
is only
0.3% of the nominal set point.
Load Regulation
Since the AP1084 is only a 3 terminal device, it is
not possible to provide true remote sensing of the
the
minimum
current
output voltage at the load. The best load regulation
is achieved when the bottom side of R2 is
connected to the load and the top-side of R1
resistor is connected directly to the case or the Vout
pin of the regulator and not to the load. It is
important to note that for high current applications,
this can re-present a significant percentage of
the overall load regulation and one must keep the
path from the regulator to the load as short as
possible to minimize this effect.
Stability
The AP1084 requires the use of an output capacitor
as part of the frequency compensation in order to
make the regulator stable. For most applications a
minimum of 10uF aluminum electrolytic capacitor
insures both stability and good transient response.
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AP1084K33A 制造商:ANACHIP 制造商全稱:Anachip Corp 功能描述:5A Low Dropout Positive Adjustable or Fixed-Mode Regulator
AP1084K33G-13 功能描述:低壓差穩(wěn)壓器 - LDO FIXED-MODE 16V 5V RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動(dòng)電壓(最大值):307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20
AP1084K33G-U 功能描述:低壓差控制器 - LDO 5A LDO POS ADJ Fixed 1.25VREF RoHS:否 制造商:Micrel 最大輸入電壓:5.5 V 輸出電壓:Adjustable 輸出電流:10 mA 負(fù)載調(diào)節(jié): 輸出類型:Adjustable, Fixed 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOT-23-6
AP1084K33L 制造商:ANACHIP 制造商全稱:Anachip Corp 功能描述:5A Low Dropout Positive Adjustable or Fixed-Mode Regulator
AP1084K33L-13 功能描述:低壓差穩(wěn)壓器 - LDO LDO BI 5.0A 1.3V 12V 1.25V 3.3V FIX RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動(dòng)電壓(最大值):307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20