LP3985IM5-2.8

Updated: 2026-09-11

Overview

The LP3985IM5-2.8 is a low-dropout (LDO) voltage regulator integrated circuit that delivers a fixed 2.8V output. Developed for power-sensitive applications, this IC maintains stable voltage levels even with fluctuating input sources. Its design prioritizes energy efficiency, making it particularly valuable for battery-operated devices where prolonged runtime is critical. The regulator's architecture incorporates advanced semiconductor technology to achieve high power supply rejection ratio (PSRR), minimizing noise in sensitive electronic circuits. As a surface-mount device in a SOT-23-5 package, it meets the miniaturization demands of modern electronics while maintaining robust performance across industrial temperature ranges.

Structure and Working Principle

The LP3985IM5-2.8 employs a PMOS pass transistor architecture that enables its low dropout capability - typically 150mV at 150mA load current. This structure allows the regulator to maintain regulation even when the input voltage approaches the output voltage, a crucial feature for battery-powered systems where voltage gradually decreases during discharge. Internal circuitry includes a precision voltage reference, error amplifier, and protection mechanisms such as thermal shutdown and current limit. The device operates by continuously comparing a fraction of the output voltage to the internal reference, adjusting the pass element to maintain constant output regardless of input variations or load changes.

Key Features

With a quiescent current of just 75µA (typical), the LP3985IM5-2.8 excels in energy-efficient applications. This ultra-low standby current significantly extends battery life in always-on devices. The IC also features excellent line and load regulation, typically maintaining output voltage within ±1% accuracy under varying conditions. The thermal shutdown protection activates at approximately 160°C, safeguarding the device from overheating damage. Additionally, the regulator demonstrates low output noise characteristics, making it suitable for powering sensitive analog circuits. Its enable pin functionality allows for power management control, further enhancing energy savings in system designs.

Application Areas

Primary applications include portable medical devices, wireless sensors, and handheld consumer electronics where stable 2.8V power is required. The regulator's compact size makes it ideal for space-constrained designs such as wearables and IoT edge devices. In industrial settings, the LP3985IM5-2.8 powers microcontroller units (MCUs), memory chips, and various low-voltage digital circuits. Its robustness against input voltage fluctuations makes it valuable in automotive electronics for infotainment systems and telematics modules, particularly in 12V battery environments where voltage regulation is critical.

Maintenance and Precautions

While the LP3985IM5-2.8 requires minimal maintenance, proper PCB layout is essential for optimal performance. Place input and output capacitors as close as possible to the respective pins to minimize impedance and improve transient response. Use low-ESR ceramic capacitors (typically 1µF) for best results. Avoid exposing the device to input voltages exceeding its absolute maximum rating (typically 6V) to prevent damage. In applications with significant load variations or high ambient temperatures, ensure adequate copper area for heat dissipation. The regulator's thermal performance can be enhanced by connecting the thermal pad (if available) to a ground plane.

B2B Procurement Guide

When sourcing the LP3985IM5-2.8, verify the manufacturer's authenticity through authorized distributors to avoid counterfeit components. Volume pricing typically becomes competitive at quantities above 1,000 units, with lead times varying from stock availability to 8-12 weeks for large orders. Consider alternative part numbers with similar specifications (such as adjustable output versions) for design flexibility. Request samples for prototype testing, and confirm RoHS compliance documentation for environmental regulations. For critical applications, inquire about extended temperature range variants (-40°C to +125°C) and automotive-grade versions if required.