The **ADP7105ARDZ-R7** is a high-performance, low-dropout (LDO) linear regulator manufactured by Analog Devices. It is designed to provide a clean, stable voltage supply for noise-sensitive precision analog circuits. --- ### ## Technical Specifications Below are the primary electrical characteristics of the ADP7105ARDZ-R7: | Parameter | Specification | | :--- | :--- | | **Input Voltage Range** | 3.3 V to 20 V | | **Output Voltage Type** | Adjustable (1.22 V to 19 V) | | **Maximum Output Current** | 500 mA | | **Dropout Voltage** | 330 mV (at 500 mA load) | | **PSRR (Power Supply Rejection Ratio)** | 80 dB at 1 kHz; 60 dB at 100 kHz | | **Output Noise** | 15 μV rms (fixed) / 0.3 × $V_{OUT}$ μV rms (adj) | | **Package Type** | 8-Lead SOIC_N_EP (Exposed Pad) | | **Operating Temperature** | -40°C to +125°C | --- ### ## Key Internal Components & Features 1. **Low Noise Architecture**: It utilizes a specialized internal reference and error amplifier to minimize output noise, making it suitable for high-speed ADCs and DACs. 2. **Soft Start (SS)**: Includes a dedicated pin to control the ramp-up speed of the output voltage, reducing inrush current during startup. 3. **Precision Enable (EN)**: The enable input has a precise threshold, allowing it to be used as a programmable UVLO (Under Voltage Lockout). 4. **Power Good (PG)**: An open-drain output that signals when the output voltage is within 90% of its nominal value. 5. **Reverse Current Protection**: Prevents damage if the output voltage is higher than the input voltage. --- ### ## Pin Configuration Summary | Pin No. | Name | Function | | :--- | :--- | :--- | | 1 | **VOUT** | Regulated Output Voltage. | | 2 | **SENSE/ADJ** | Feedback input for setting/sensing output voltage. | | 3 | **GND** | Ground. | | 4 | **SS** | Soft Start; connect a capacitor to adjust start time. | | 5 | **EN** | Enable Input; drive high to turn on the regulator. | | 6 | **PG** | Power Good; indicates stable output. | | 7 | **NC** | No Connection. | | 8 | **VIN** | Input Supply Voltage. | | **EP** | **Exposed Pad** | Should be soldered to the PCB ground plane for thermal dissipation. | --- ### ## Typical Application Circuit To set the output voltage ($V_{OUT}$), a resistor divider is connected to the ADJ pin: ```text VOUT = 1.22 V × (1 + R1 / R2) ``` Where: * **R1** is the resistor between VOUT and ADJ. * **R2** is the resistor between ADJ and GND. * **C_IN / C_OUT**: Typically 2.2 μF ceramic capacitors are required for stability. ---