The **ADP7185ACPZN3.0-R7** is a high-performance, low-dropout (LDO) linear regulator manufactured by Analog Devices. It is specifically designed for high-precision applications requiring low noise and high power supply rejection. --- ### ## Technical Specifications | Parameter | Specification | | :--- | :--- | | **Output Voltage** | Fixed 3.0V | | **Input Voltage Range** | -2.0V to -5.5V | | **Maximum Output Current** | 500 mA | | **Dropout Voltage** | 190 mV (typical at 500 mA) | | **Output Noise** | 4 μV rms (10 Hz to 100 kHz) | | **PSRR** | 68 dB at 10 kHz; 40 dB at 1 MHz | | **Package** | 8-Lead LFCSP (3mm x 3mm) | | **Operating Temperature** | -40°C to +125°C | --- ### ## Key Electronic Features 1. **Low Noise Operation:** With an output noise of only 4 μV rms, this part is ideal for powering sensitive analog components like ADCs, DACs, and precision amplifiers without introducing switching interference. 2. **Negative Voltage Regulation:** Unlike standard positive LDOs, this is a **Negative LDO**. It regulates a negative input voltage to a stable -3.0V output (relative to ground). 3. **High PSRR:** The high Power Supply Rejection Ratio (PSRR) ensures that ripples from a primary switching power supply are filtered out before reaching the load. 4. **Precision Enable:** Includes an enable pin (`EN`) that allows the device to be turned on or off with logic-level signals. 5. **Adjustable Soft Start:** Uses an external capacitor to control the start-up time, limiting inrush current. --- ### ## Pin Configuration (LFCSP-8) | Pin No. | Mnemonic | Description | | :--- | :--- | :--- | | 1 | VOUT | Regulated Negative Output Voltage. | | 2-3 | SENSE/ADJ | Sense input for fixed versions or feedback for adjustable versions. | | 4 | GND | Ground Reference. | | 5 | EN | Enable input (Active High). | | 6 | SS | Soft Start pin (connect capacitor to GND). | | 7-8 | VIN | Negative Input Voltage. | | EP | Exposed Pad | Must be connected to GND for thermal dissipation. | --- ### ## Application Circuit Example To ensure stability, the ADP7185 requires specific input and output capacitors. ```c // Typical Configuration Requirements: // 1. Input Capacitor (Cin): 4.7 uF (Low ESR Ceramic) // 2. Output Capacitor (Cout): 4.7 uF (Low ESR Ceramic) // 3. Soft Start (Css): Optional (e.g., 10 nF for gradual ramp) ``` ---