The **ADM7172ACPZ-3.3-R7** is a high-performance, ultra-low noise, high Power Supply Rejection Ratio (PSRR) CMOS Linear Regulator (LDO). It is designed specifically for high-performance analog and mixed-signal circuits that require a very clean power supply. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Output Voltage (Fixed)** | 3.3 V | | **Input Voltage Range** | 2.3 V to 6.5 V | | **Maximum Output Current** | 2 A | | **PSRR (at 100 kHz)** | 60 dB | | **RMS Noise (10 Hz to 100 kHz)** | 5 μV | | **Low Dropout Voltage** | 170 mV (typical at 2 A load) | | **Package Type** | 8-Lead LFCSP (3mm x 3mm) | --- ### 2. Core Functional Parts & Features #### A. Internal Error Amplifier The device features a high-gain error amplifier that compares the internal reference voltage to the output voltage. It is optimized for fast transient response, meaning it can handle sudden changes in load current without significant voltage spikes. #### B. Precision Enable (EN) Pin The Enable pin allows the LDO to be turned on or off. It has a precision threshold (typically 1.2V), which allows it to function as a programmable Under-Voltage Lockout (UVLO) using an external resistor divider. #### C. Soft Start (SS) Pin To prevent "Inrush Current" (a sudden surge of current when the device starts), the SS pin allows the user to connect a capacitor. This capacitor dictates how slowly the output voltage ramps up to its target 3.3V. #### D. Thermal and Overcurrent Protection * **Thermal Shutdown:** If the internal temperature exceeds a safe limit (typically 150°C), the device shuts down to prevent permanent damage. * **Current Limit:** Protects the device and the load from short-circuit conditions. --- ### 3. Application Use Cases Due to its low noise profile, this part is commonly used in: 1. **ADC/DAC Powering:** Ensuring high-speed converters operate at maximum resolution without interference. 2. **RF Applications:** Powering Phase-Locked Loops (PLLs) and Voltage Controlled Oscillators (VCOs). 3. **Medical Instrumentation:** Where high precision and low signal interference are critical. --- ### 4. Part Number Breakdown * **ADM7172:** The base model (2A Low Noise LDO). * **ACPZ:** "A" (Temperature range), "CP" (LFCSP package), "Z" (RoHS compliant). * **3.3:** Indicates the fixed 3.3V output version. * **R7:** Indicates 7-inch reel packaging (typically 1,500 units).