STMicroelectronics LD2985BM50R Linear Voltage Regulator IC - 5V Fixed Output, 150mA, SOT-23-5 Package

STMicroelectronics LD2985BM50R Linear Voltage Regulator: High-Performance 5V Fixed Regulator in SOT-23-5 Package

In modern electronic systems, precise voltage regulation is critical for ensuring optimal performance and reliability. The STMicroelectronics LD2985BM50R linear voltage regulator stands out as a compact yet powerful solution for applications requiring a stable 5V output at up to 150mA of current. Housed in a space-saving SOT-23-5 package, this device combines low quiescent current, excellent line regulation, and advanced protection features to meet the demands of industrial, automotive, and embedded systems. This article explores the technical specifications, unique advantages, and practical applications of the LD2985BM50R, making it an essential component for engineers seeking reliable voltage regulation in constrained spaces.

Key Technical Specifications

At its core, the LD2985BM50R delivers a fixed 5V output with minimal voltage dropout (0.575V @ 150mA) and exceptional stability across operating conditions. Designed to accept input voltages up to 16V, this regulator maintains consistent performance even when power sources fluctuate. Its low quiescent current of 150 µA ensures minimal power consumption during standby modes, making it ideal for battery-powered applications where energy efficiency is paramount. The device also features a 45dB PSRR (Power Supply Rejection Ratio) at 1kHz, effectively filtering noise and ripple from upstream power supplies.

Advanced Protection Features

Engineers working in harsh environments will appreciate the LD2985BM50R's built-in protection mechanisms. The device integrates over-temperature and over-current safeguards to prevent damage during fault conditions. These protections ensure reliable operation even in automotive systems exposed to extreme temperatures or industrial applications prone to electrical transients. The enable control feature allows designers to implement power sequencing strategies, further enhancing system stability during startup and shutdown phases.

Compact Packaging for Space-Constrained Designs

One of the LD2985BM50R's most significant advantages lies in its SOT-23-5 packaging. This ultra-compact surface-mount format enables integration into densely populated PCBs without compromising thermal performance. Compared to traditional regulator packages, the SOT-23-5 footprint reduces board space requirements by up to 40% while maintaining mechanical robustness. This makes the device particularly well-suited for portable electronics, IoT devices, and sensor modules where miniaturization is critical.

Performance Comparison with Industry Standards

When benchmarked against competing solutions like the LM1117 or AP2112 series, the LD2985BM50R demonstrates superior transient response and lower dropout characteristics. Its 0.575V dropout voltage at full load enables operation closer to the output voltage rail than many alternatives, extending battery life in portable applications. Additionally, the device's 45dB PSRR outperforms standard regulators by 20-30%, making it particularly effective in noise-sensitive RF circuits and precision analog systems.

Practical Applications and Design Considerations

The LD2985BM50R's versatility shines in diverse applications. In automotive electronics, it provides stable 5V power for ECUs and sensor interfaces while withstanding load dumps up to 16V. For industrial automation systems, its wide temperature range (-40°C to 125°C) ensures reliable operation in harsh factory environments. Designers should consider implementing a 1µF ceramic capacitor at the input and a 4.7µF capacitor at the output to optimize stability, as recommended in STMicroelectronics' datasheet. When using multiple regulators in parallel, thermal vias beneath the PCB footprint help dissipate heat efficiently.

Tags: LD2985BM50R, SOT-23-5, 5V Regulator, Linear Voltage Regulator, STM IC