Micropower, 200 mA Ultra Low-Dropout Voltage Regulator with Programmable Power-On Reset Delay# Technical Datasheet: LP2987IMX30 Low-Dropout (LDO) Voltage Regulator
Manufacturer : National Semiconductor (now part of Texas Instruments)
Component : LP2987IMX30 (30V, 150mA, Ultra-Low Noise, High PSRR LDO Regulator in SOT-23 Package)
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## 1. Application Scenarios
### Typical Use Cases
The LP2987IMX30 is a precision, low-dropout voltage regulator designed for applications requiring very clean, stable power from a higher voltage or noisy input source. Its core function is to provide a tightly regulated, low-noise output voltage (up to 30V input, fixed 3.0V output for the "30" variant) while consuming minimal quiescent current.
Primary use cases include:
* Post-Regulation for Switching Supplies: It is ideal for cleaning up the noisy output of DC-DC switching regulators or AC-DC power supplies, providing a pristine voltage rail for noise-sensitive analog circuits.
* Battery-Powered Equipment: In devices powered by multi-cell Li-ion, Li-Poly, or alkaline battery packs (e.g., 9V, 12V, 24V), it efficiently steps down the variable battery voltage to a stable 3.0V logic supply as the battery discharges.
* Powering Noise-Sensitive Analog Circuits: Its ultra-low output noise (~30µVrms typical) and high Power Supply Rejection Ratio (PSRR) make it indispensable for powering:
* RF/IF circuitry (VCOs, PLLs, LNAs)
* High-resolution Analog-to-Digital Converters (ADCs) and Digital-to-Analog Converters (DACs)
* Precision voltage references and sensor signal conditioning circuits (e.g., for medical devices, instrumentation)
* Microcontroller & Logic Supply: Provides a clean, reliable 3.0V rail for microcontrollers, FPGAs, memory, and digital logic in systems where the primary supply is significantly higher or noisy.
### Industry Applications
* Automotive Infotainment & Telematics: Powers audio codecs, tuners, and GPS modules where electrical noise from the vehicle's 12V system must be rejected.
* Industrial Instrumentation & Control: Used in data acquisition systems, process controllers, and sensor interfaces that require high precision and reliability.
* Medical Electronics: Suitable for portable monitors, diagnostic equipment, and imaging systems where signal integrity is critical.
* Communications Infrastructure: Provides clean power for clock distribution circuits, SERDES, and optical module controllers in base stations and networking gear.
* Consumer Audio/Video: Powers high-fidelity audio amplifiers, video processors, and set-top box components.
### Practical Advantages and Limitations
Advantages:
* High Input Voltage Capability: Supports inputs up to 30V, allowing direct regulation from common industrial and automotive voltages.
* Excellent Noise Performance: Ultra-low noise and high PSRR (>70dB at 1kHz) ensure a clean output even with a noisy input.
* Low Dropout Voltage: Typically 300mV at 150mA load, maximizing efficiency and extending battery life in dropout conditions.
* Low Quiescent Current: Typically 80µA, minimizing power loss in always-on applications.
* Stable with Ceramic Capacitors: Designed for stability with small, low-ESR ceramic output capacitors (≥2.2µF), saving board space and cost.
* Integrated Protection: Features current limit and thermal shutdown for robust operation.
Limitations:
* Fixed Output Voltage: The "IMX30" variant provides a fixed 3.0V output. Other voltages require a different part number.
* Limited Output
