A linear and low-dropout regulator (LDO regulator) is a very simple and economical regulator that is used to provide a regulated o/p voltage that is simply powered from a high input voltage in different applications. A regulator operates at an extremely low potential difference between the I/O voltages so the use of this regulator will help in controlling the increase of heat & allow efficient energy usage. There are many LDO regulators which are most frequently used in different applications like AMS1117, MIC29302, LM1117, and RT9193. This article provides brief information on AMS1117 LDO Regulator – working and its applications.
What is AMS1117 LDO Regulator?
The AMS1117 is a popular 3-pin LDO regulator and is available in various models for adjustable & fixed voltage requirements. This voltage regulator delivers 1A a maximum current & the output voltage varies from 1.5- 5V. When this IC operates at maximum current then it has 1.3V of low drop-out voltage. The AMS1117 LDO regulator is commonly used for high-efficiency linear regulation & post-regulation switching supplies. This regulator is available in three packages; surface mount SOT-223, 8L SOIC & TO-252 (DPAK) plastic package.
AMS1117 LDO Regulator Pin Configuration:
The pin configuration of the AMS1117 LDO regulator with a symbol is shown below. This regulator includes three pins and each pin is discussed below.
- Pin1 (Adjust/GND): This pin is used to adjust the o/p voltage. If this regulator is a fixed voltage regulator then it acts as GND.
- Pin2 (Vout): This is the output voltage pin where the regulated o/p voltage set through the adjust pin can be acquired from this pin.
- Pin3 (Vin): This is the input voltage pin where this pin obtains the input voltage then it is regulated & produced at the o/p voltage.
Features & Specifications:
The features and specifications of the AMS1117 LDO regulator are discussed below.
- It is a three-terminal fixed or adjustable voltage regulator.
- The type of fixed voltage is; 1.5V, 1.8V, 2.5V, 2.85V, 3.3V & 5V.
- The range of adjustable voltage is from 1.25V – 13.8V.
- It is incorporated in thermal & current limiting shield.
- The output current is 1000mA.
- The operating junction temperature (Tj) is 125°C.
- The drop-out voltage maximum is 1.3V.
- It operates down to 1Volt Dropout
- Its line regulation maximum is 0.2%.
- Its load regulation maximum is 0.4%.
Alternative AMS1117 Voltage Regulators
The alternative AMS1117 LDO voltage regulators are; LM317, LM1117, NTE9060 & LM7805.
AMS1117 LDO Regulator Circuit Diagram
Generally, the AMS1117 LDO regulator is classified into two types based on the package and output voltage like the fixed and adjustable voltage regulators. These two LDO regulators are discussed with circuit diagrams.
The circuit diagram of a fixed voltage regulator is shown below. Using the AMS1117 LDO regulator is practically simple. If it is a fixed-type voltage regulator then this IC is simply powered through the Vin pin & the regulated o/p can be attained in the Vout pin. In this type, the Adj/Ground pin works like a GND pin, so it is grounded. In addition, a capacitor is connected to this circuit at the o/p side to remove the noise.
The circuit diagram of an adjustable voltage regulator is shown below. This circuit uses two external resistors like R1 & R2 to decide the regulator’s output voltage. The ‘CAdj’ capacitor component is optional that can be utilized to enhance ripple rejection if necessary. The input & output noise can be filtered out by the capacitor.
To calculate the AMS1117 regulator’s output voltage, the following formula is used. Choose the resistors like R1 & R2 values depending on the required output voltage for your application. Remember that the R1 resistor value must be small than 1k. So, a variable resistor is used at ‘R2’ if you desire to change the voltage in real-time.
VOUT = VREF (1 + R2/R1) + IADJR2
Thus, the AMS1117 LDO regulator is used as a fixed voltage or adjustable voltage regulator frequently in the battery charging circuits.
5V to 3.3V AMS117 Voltage Regulator Circuit
Generally, a voltage regulator is used for adjusting or controlling the voltages of an electronic circuit. The circuit diagram of the 5V to 3.3V AMS117 voltage regulator circuit is shown below. It takes any input voltage & changes it into a lower or higher voltage based on the requirement of the circuit. To design this circuit, the AMS117 voltage regulator IC is used. This voltage regulator is commonly used to regulate 5V to 3.3V. In addition, its o/p current is 1000mA & the highest drop-out voltage is 1.3V.
The required components to design this 5V to 3.3V AMS117 voltage regulator circuit mainly include AMS1117 Voltage Regulator IC, LED, 10uF ceramic capacitors – 2, 220 Ohm resistor, and two pin connector.
The input DC supply is directly applied to the Vi Pin & output 3.3V is taken from Vo Pin directly. For both input & output voltages, there is a common ground pin. Once the input DC supply is provided, the LED will glow to illustrate that there is a supply. For the filtering purpose, capacitors C1 & C2 are utilized. The regulated o/p is taken at pin2 of Ic. This circuit is very simple to design & also to understand.
This circuit is utilized in positive voltage regulation and also different circuits like current limiting, motor control & reverse polarity. This is frequently used to make consumer products.
The applications of the AMS1117 LDO regulator are discussed below.
- The AMS1117 LDO regulator is used for post-regulation & high-efficiency linear regulation switching supplies.
- This linear voltage regulator is used in the circuit to change the flow of voltage from the i/p to the o/p of the circuit.
- It is used in variable power supply.
- It is used for regulations of positive voltage.
- It is used in Desktop PC systems, DVDs & various consumer products.
- It is used in portable electronic devices which need low DC power.
- The other applications of this regulator mainly include different electrical circuits, computers, solar panel circuits, TV circuits, printers, medical devices, etc.
Please refer to this link for AMS1117 LDO Regulator Datasheet.
Thus, this is an overview of AMS1117 LDO regulator–pin configuration, specifications, circuit, working, and its applications. The AMS1117 LDO voltage regulator is a series of fixed & adjustable regulators. This regulator is very simple to utilize and is protected against thermal overloads & short circuits. These ICs offer many benefits like low dropout voltage, more accurate reference tolerance & better reference stability through temperature. Here is a question for you, what is an LDO stand for?