The **ADP7158ACPZ-3.3-R7** is a high-performance, ultra-low noise, high Power Supply Rejection Ratio (PSRR) linear regulator (LDO) manufactured by Analog Devices. It is specifically designed to provide clean power to noise-sensitive precision analog circuits. --- ### ## Technical Specifications | Parameter | Value | | :--- | :--- | | **Output Voltage (Fixed)** | 3.3 V | | **Input Voltage Range** | 2.3 V to 5.5 V | | **Maximum Output Current** | 2 A | | **Noise (10 Hz to 100 kHz)** | 0.9 µV rms | | **PSRR (at 100 kHz)** | 70 dB | | **Dropout Voltage (at 2 A)** | 120 mV (Typical) | | **Package Type** | LFCSP-10 (3mm x 3mm) | | **Operating Temperature** | -40°C to +125°C | --- ### ## Key Electronic Features 1. **Ultra-Low Noise Architecture:** With a noise floor of just **0.9 µV rms**, this LDO is among the quietest in the industry. This is critical for applications like high-speed ADCs/DACs where power supply noise can directly translate into signal jitter or distortion. 2. **High PSRR:** It effectively filters out ripples from switching regulators (DC-DC converters) that might precede it in the power chain, ensuring a stable DC output. 3. **Soft Start Capability:** The device includes a dedicated programmable soft-start pin. By connecting a capacitor to the `SS` pin, you can control the ramp-up time of the output voltage to prevent inrush current. 4. **Precision Enable:** The `EN` pin allows the chip to be turned on or off. It has a precise threshold, allowing it to be used for power sequencing or undervoltage lockout (UVLO) functions. --- ### ## Pin Configuration (LFCSP-10) The ADP7158 uses a 10-lead Lead Frame Chip Scale Package. Below is the functional breakdown of the key pins: | Pin Name | Function | | :--- | :--- | | **VOUT** | Regulated 3.3V output. | | **VIN** | Input power supply. | | **VREG** | Output of the internal regulator providing power to the control circuitry. | | **REF** | Reference voltage filter pin; requires a bypass capacitor to ground. | | **BYP** | Bypass pin for noise reduction; requires a capacitor. | | **SS** | Soft-start pin to control voltage ramp rate. | | **EN** | Enable input. Drive high to turn on the device. | | **EP** | Exposed Pad (Ground). Must be soldered to the PCB for thermal dissipation. | --- ### ## Typical Application Circuit Code (Concept) While this is a hardware component, in a PCB design environment (like Altium or KiCad), the electrical net connections would look similar to this logic: ```cpp // Schematic Connection Logic Component LDO1 = ADP7158ACPZ_3.3_R7; LDO1.VIN = Power_Rail_5V; LDO1.VOUT = Sensitive_Analog_Rail_3.3V; LDO1.GND = System_Ground; LDO1.EN = MCU_GPIO_Power_Enable; // External Capacitors (Required for Stability) C_IN = 10uF; // Ceramic C_OUT = 10uF; // Ceramic C_REF = 1uF; // Noise filtering ``` --- ### ## Applications * **RF Components:** Phase-locked loops (PLLs) and Voltage-controlled oscillators (VCOs). * **Instrumentation:** High-resolution data converters (24-bit ADCs). * **Medical:** Ultrasound and imaging equipment. * **Networking:** Optical modules and high-speed clocking.