**ADP170AUJZ-8-R7: A Comprehensive Technical Overview of Analog Devices' 200 mA Low-Noise LDO Voltage Regulator**

In the realm of power management, achieving clean, stable, and efficient voltage regulation is paramount for the performance of sensitive analog and RF circuits. The **ADP170AUJZ-8-R7** from Analog Devices stands out as a critical component in this pursuit, offering a compelling blend of low noise, high accuracy, and robust performance in a minuscule package. This article provides a detailed technical examination of this low-dropout (LDO) linear regulator.

**Core Architecture and Operating Principle**

As a CMOS-based LDO regulator, the ADP170AUJZ-8-R7 is designed to provide a fixed **8.0 V output** from an input supply ranging from 2.5 V to 12 V. Its core architecture includes a voltage reference, error amplifier, feedback network, and a pass transistor. The device operates by comparing a scaled version of the output voltage to a precise internal bandgap reference. The error amplifier then adjusts the conductance of the P-MOSFET pass element to maintain a constant output voltage, even as input voltage or load current changes.

The key to its performance lies in its CMOS construction. Unlike bipolar LDOs, which can suffer from higher ground current, the CMOS design enables a very **low ground current of 30 μA (typical)**, making it exceptionally efficient under light loads. This is crucial for battery-powered applications.

**Defining Characteristics and Performance**

The ADP170AUJZ-8-R7 is engineered to excel in several key areas:

1. **Ultra-Low Noise Performance:** This is arguably its most significant feature. The LDO incorporates a proprietary design that achieves an ultra-low output noise of **9 μV rMS (typical)** over a 10 Hz to 100 kHz bandwidth. For the most noise-sensitive applications, it includes a dedicated **BYPASS pin**. Connecting a small ceramic capacitor (10 nF to 100 nF) to this pin dramatically reduces the noise contribution from the internal reference, pushing noise performance to as low as **6.5 μV rMS**.

2. **High Power Supply Rejection Ratio (PSRR):** The regulator effectively attenuates ripples and noise from the input supply. It boasts an impressive **PSRR of 70 dB at 1 kHz**, ensuring that disturbances on the input line do not propagate to the clean, regulated output. This high PSRR remains effective up to several tens of kilohertz.

3. **Excellent Accuracy and Load Regulation:** The device offers a high **output voltage accuracy of ±0.8%** at +25°C, ensuring the 8.0 V output is precise and reliable. Furthermore, it maintains excellent line and load regulation (0.04%/V and 0.04%/mA, respectively), meaning the output voltage remains stable despite fluctuations in input voltage or output current.

4. **Robust Protection Features:** The ADP170AUJZ-8-R7 is equipped with comprehensive protection mechanisms, including **current limiting** and **thermal shutdown**, which safeguard both the regulator and the downstream load under fault conditions.

**Application Spectrum**

The combination of low noise, high PSRR, and small form factor (5-lead TSOT package) makes this LDO ideal for powering:

* **Precision Analog-to-Digital Converters (ADCs) and Digital-to-Analog Converters (DACs)**

* **Voltage-Controlled Oscillators (VCOs) and Phase-Locked Loops (PLLs)**

* **Medical and Scientific Instrumentation**

* **RF and Communication Systems**

* **Portable and Battery-Powered Equipment**

**ICGOODFIND**

The ADP170AUJZ-8-R7 is a quintessential solution for designers who cannot compromise on power quality. Its industry-leading low-noise output, superior PSRR, and high efficiency set a high bar for performance in its class. For any application where noise on the power rail could degrade signal integrity, this LDO from Analog Devices provides a robust, high-performance, and space-efficient answer.

**Keywords:**

1. **Low-Noise LDO Regulator**

2. **High PSRR**

3. **200 mA Output Current**

4. **Ultra-Low Ground Current**

5. **BYPASS Pin**