## Technical Overview of AD5273BRJZ10-R2 The **AD5273** is a 64-position, one-time programmable (OTP) digital potentiometer. It is designed to replace mechanical trimmers and variable resistors in electronic circuits, offering the advantage of digital control and permanent setting capability. ### 1. Key Specifications | Feature | Specification | | :--- | :--- | | **Resolution** | 64 Positions (6-bit) | | **Resistance Values** | 1 kΩ, 10 kΩ, 50 kΩ, 100 kΩ | | **Interface** | I²C Compatible | | **Programmability** | One-Time Programmable (OTP) | | **Supply Voltage** | 2.7 V to 5.5 V | | **Temperature Range** | -40°C to +125°C | | **Package** | SOT-23-8 | --- ### 2. Functional Components The AD5273 consists of several internal electronic blocks that allow it to function as a digitally controlled resistor: #### A. Resistor Network The core of the device is a string of fixed resistors. A CMOS switch connects the "wiper" terminal to one of the 64 tap points along this string, determined by the digital input. #### B. I²C Serial Interface The part communicates via a standard 2-wire I²C interface (SDA and SCL pins). This allows a microcontroller to: * Adjust the wiper position dynamically. * Trigger the "Fuse" blowing command to lock the resistance permanently. #### C. OTP (One-Time Programmable) Memory Unlike standard volatile digital pots that reset to a default value upon power-down, the AD5273 features **OTP technology**. * **Volatile Mode:** You can change the wiper position as many times as you want during testing. * **Permanent Mode:** Once the desired resistance is found, a specific command "blows" an internal fuse, locking the wiper position as the new power-on default. --- ### 3. Pin Configuration | Pin Number | Name | Description | | :--- | :--- | :--- | | 1 | **W** | Wiper terminal | | 2 | **Vdd** | Positive power supply | | 3 | **GND** | Ground | | 4 | **SCL** | I²C Serial Clock | | 5 | **SDA** | I²C Serial Data | | 6 | **Vp** | Programming Voltage (needed for OTP) | | 7 | **B** | Bottom terminal of resistor | | 8 | **A** | Top terminal of resistor | --- ### 4. Typical Applications * **Calibration:** Replacing mechanical trimmers in precision analog circuits. * **Sensor Trimming:** Adjusting gain or offset in sensor signal conditioning. * **Power Supply Adjustment:** Setting output voltages in DC-DC converters. * **LCD Contrast Control:** Adjusting the bias voltage for displays. --- ### 5. Programming the OTP To permanently set the resistance, the **Vp pin** must be connected to an external 6V source during the programming cycle. Without this high-voltage pulse, the device will remain in volatile mode, losing its setting whenever power is disconnected.