The **ADP151ACBZ-2.5-R7** is an ultra-low noise, low dropout (LDO) linear regulator produced by Analog Devices. It is specifically designed to provide high performance in space-constrained applications. --- ### ## Technical Specifications Below are the key electrical characteristics of the device: | Parameter | Value / Specification | | :--- | :--- | | **Output Voltage** | 2.5V (Fixed) | | **Input Voltage Range** | 2.2V to 5.5V | | **Max Output Current** | 200 mA | | **Dropout Voltage** | 140 mV (at 200 mA load) | | **Quiescent Current** | 10 $\mu$A (No load) | | **PSRR** | 70 dB at 10 kHz | | **Noise** | 9 $\mu$V rms (10 Hz to 100 kHz) | | **Package** | 4-ball WLCSP (Wafer Level Chip Scale Package) | --- ### ## Core Electronic Features ### 1. Ultra-Low Noise Performance The ADP151 is engineered to operate without a bypass capacitor, yet it maintains an exceptionally low noise floor ($9 \mu V$). This makes it ideal for powering noise-sensitive components like: * RF Transceivers * Precision Analog-to-Digital Converters (ADCs) * High-fidelity audio circuits ### 2. High Power Supply Rejection Ratio (PSRR) With a PSRR of 70 dB at low frequencies, this part effectively filters out ripples coming from upstream switching power supplies (DC-DC converters), ensuring a clean stable rail for sensitive downstream electronics. ### 3. Efficiency and Low Power * **Low Dropout:** The 140 mV dropout voltage allows the regulator to maintain 2.5V output even when the input battery voltage drops very close to the target voltage. * **Low Ground Current:** At 10 $\mu$A (idle) and roughly 265 $\mu$A at full load, it minimizes battery drain in portable devices. ### 4. Protection Circuitry The chip includes internal safety features: * **Thermal Overload Protection:** Shuts down the device if it overheats. * **Short-Circuit Protection:** Prevents damage if the output is grounded. --- ### ## Pin Configuration (WLCSP) Since this is a 4-ball WLCSP package, the layout is extremely compact: | Pin | Symbol | Function | | :--- | :--- | :--- | | A1 | **VIN** | Regulator Input Supply | | A2 | **VOUT** | Regulated Output Voltage (2.5V) | | B1 | **EN** | Enable Input (High = On, Low = Off) | | B2 | **GND** | Ground Reference | --- ### ## Typical Application Circuit The device is designed for stability with small $1 \mu F$ ceramic input and output capacitors. ```mermaid graph LR Vin[Input 2.2V-5.5V] --> C1(1uF Cap) C1 --> ADP[ADP151] ADP --> C2(1uF Cap) C2 --> Vout[2.5V Output] EN[Enable Signal] --> ADP ``` ---