AMS11171A LDO Regulator – Fixed/Variable

TheAMS1117是一个受欢迎的SMD软件包3-pin voltage regulatorthat is available in many models for fixed and adjustable voltage requirements. The IC can deliver a maximum current of 1A and the output voltage can vary from 1.5V to 5V. It also has a low drop out voltage of 1.3V when operating at maximum current.

引脚配置

Pin Number	Pin Name	Description
1	Adjust/Ground	该引脚可以调整输出电压，如果是固定电压调节器，则可以作为地面
2	Output Voltage (Vout)	调节引脚设置的调节输出电压可以从此引脚获得
3	输入电压（VIN）	The input voltage which has to be regulated is given to this pin

特征

• Fixed/Adjustable 3-terminal Linear voltage regulator
• Low Drop-Out (LDO) Voltage regulator
• Fixed Voltage type: 1.5V, 1.8V, 2.5V, 2.85V, 3.3V and 5V
• Variable Voltage range: 1.25V to 13.8V
• Output current is 1000mA
• Maximum Drop-out Voltage: 1.3V
• In-built Current Limiting and thermal protection.
• Operating junction temperature is 125°C
• Available in SOT-223, TO-252 and SO-8 Package

Note:Complete Technical Details can be found at the datasheet provided at the end of this page.

替代电压调节器：LM317,LM7805,NTE9060

Alternative for AMS1117:LM1117

Where to use AMS1117

就像著名的7805一样，LM317 AMS1117也是另一个线性电压调节器。它以其较小的外形而闻名，因为它可作为DCY软件包（SMD组件）提供。基于包装和输出电压，LM1117的类型多种多样。但是所有IC的额定值为1A的最大电流。下表将帮助您为IC选择正确的零件号。

The IC is popularly known for being used in Arduino boards to regulate 5V and 3.3V. So if you are looking for a SMD component voltage regulator then this IC might be the right choice for you.

How to use AMS1117

Using the AMS1117 is pretty much straight forward. If it a fixed voltage regulator just power the IC though the Vin pin and the regulated output can be obtained in the Vout pin. The Adj/Ground pin in this case acts only as a ground pin and is grounded. Also a capacitor can be added at the output side to filter out the noise. The circuit diagram for a variable output regulator is show below

For an Adjustable type voltage regulator we need two external resistors to decide the output voltage of the Regulator. A reference circuit diagram for adjustable voltage is shown below, where the resistors R1 and R2 decides the output voltage of the regulator. The capacitor CAdj is an optional component which can be added to improve ripple rejection if required. The other two capacitors are to filter the input and output noise respectively.

The formulae to calculate the output voltage of AMS1117 regulator is given below. Select the value of R1 and R2 based on the output voltage required for your project. Keep in mind that the value of R1 should be less than 1k. You can use a variable resistor at R2 if you want to vary the voltage in real time.

V_OUT= V_REF(1 + R₂/ R₁) + I_ADJR2

有能力作为一个固定的voltage or a variable voltage regulator the AMS1117 often finds its application in battery charging circuit and can also be designed to provide negative voltage if required. Refer the datasheet at the end of this page to find more application circuits for this IC.

申请

• Used for Positive voltage regulations
• Variable power supply
• 当前的限制电路
• 反向极性电路
• Commonly used in Desktop PC, DVD and other consumer products
• Used in motor control circuits

2D – Model of LM1117 (DCY Package)