## Overview of ADM7155ARDZ-03-R7 The **ADM7155ARDZ-03-R7** is a high-performance, ultra-low noise, high Power Supply Rejection Ratio (PSRR) linear regulator (LDO). It is specifically designed to provide clean power to noise-sensitive precision analog and mixed-signal circuits. --- ### Key Specifications | Feature | Specification | | :--- | :--- | | **Manufacturer** | Analog Devices Inc. (ADI) | | **Output Voltage** | 3.3 V (Fixed Version) | | **Input Voltage Range** | 2.3 V to 5.5 V | | **Maximum Output Current** | 600 mA | | **RMS Noise** | 0.9 µV (typical, 100 Hz to 100 kHz) | | **PSRR** | > 90 dB (1 kHz to 100 kHz) | | **Package Type** | 8-Lead SOIC_N_EP (Exposed Pad) | | **Operating Temperature** | -40°C to +125°C | --- ### Core Functional Features * **Ultra-Low Noise:** With an RMS noise of less than 1 µV, it is ideal for powering VCOs (Voltage Controlled Oscillators), PLLs (Phase-Locked Loops), and high-resolution ADCs. * **High PSRR:** It effectively filters out ripples from switching power supplies, ensuring a stable and "quiet" DC output. * **Precision Accuracy:** Offers ±2% output voltage accuracy over line, load, and temperature variations. * **Soft Start:** Includes an adjustable soft start to minimize inrush current during startup. * **Protection Circuitry:** Features internal thermal shutdown and current-limit protection to prevent damage under fault conditions. --- ### Pin Configuration (8-Lead SOIC) | Pin No. | Mnemonic | Description | | :--- | :--- | :--- | | 1 | **VOUT** | Regulated Output Voltage. | | 2 | **VOUT_S** | Output Voltage Sense input for tight regulation. | | 3 | **VREG** | Regulated Voltage for internal circuitry (requires capacitor). | | 4 | **VIN** | Input Supply Voltage. | | 5 | **EN** | Enable Input. High = On, Low = Off. | | 6 | **BYP** | Bypass capacitor connection for noise reduction. | | 7 | **REF** | Reference voltage output/input. | | 8 | **GND** | Ground. | | **EP** | **Exposed Pad** | Must be soldered to PCB ground for thermal dissipation. | --- ### Typical Application Circuit ```text Input (2.3V-5.5V) ----[ VIN ]-------[ ADM7155 ]-------[ VOUT ]---- Output (3.3V) | | | [Cin] [GND] [Cout] | | | Ground Ground Ground ``` --- ### Ordering Information Detail The suffix **-03** indicates the fixed output voltage (3.3V), and **-R7** indicates the packaging format (7-inch tape and reel, usually containing 1,000 units).