Most of the lithium ion batteries are designed with 3.7 to 4.2v. Some microcontrollers and sensors only need a stable 3.3V DC supply, so connecting this battery directly to the circuit will damages the components. In this article, i will show you how to build a reliable and efficient 3.7V to 3.3V regulator circuit using AP2112K 3.3TRG1 IC. in this project you can connect the 3.7V battery to the circuit and take output of constant and stable 3.3V DC supply.
AP2112K-3.3TRG1 Pinout
The AP2112K-3.3TRG1 is a low dropout linear voltage regulator IC. This IC is designed to give a stable 3.3V DC with the current of 600mA. The IC is comes with SOT-25 package. This regulator IC has the feature of low dropout voltage (LDO) and quiescent current, So this IC is suitable for power sensitive circuits such as microcontrollers and sensors. The IC is also have protection features like thermal shutdown and over current limiting. The additional enable pin is used for efficient power management in various electronic circuits.
Pinout Configuration
| Pin Number | Pin Name | Description |
| 1 | VIN | Input Voltage |
| 2 | GND | Ground |
| 3 | EN | Enable |
| 4 | NC | No Connection |
| 5 | VOUT | Output Voltage |
Circuit Diagram
In this circuit PIN 1 of AP2112K IC is connecting to the positive supply of input voltage. The input voltage is around 3.7V DC comes from the lithium battery. The PIN2 isconnected to the ground or negative supply of battery.
The Pin 3 is Enable pin, you can connect it into the input positive voltage or you can control the IC using another microcontroller like turn on/off the entire circuit. A 10uf capacitor is using in voltage input section and also in voltage output section. This capacitor provide the stability of input and output voltage and also filter the DC voltage.
The 100nf capacitor will filter the high frequency noise generated by the circuit. overall the AP2112K voltage reulator IC and capacitors providing a stable 3.3V DC in output section for powering other microcontroller IC and Sensors safely.
