Texas Instruments LP3982ILD-1.8

Overview

LP3982ILD-1.8 from Texas Instruments (formerly National Semiconductor) is a micropower, ultra low-dropout, low-noise 300mA CMOS linear regulator delivering a fixed 1.8V output. It features 120mV typical dropout at 300mA, 90µA typical quiescent current, and 1nA shutdown current-enabling extended battery life in portable electronics such as wireless handsets and DSP core supplies.

For engineers reviewing the LP3982ILD-1.8 datasheet, LP3982ILD-1.8 pinout, LP3982ILD-1.8 application, or LP3982ILD-1.8 equivalent, key selection criteria include its MSOP-8/LLP-8 package compatibility with MAX8860, stability with 2.2µF ceramic output capacitors, ±2% output voltage tolerance, and integrated FAULT detection for overcurrent/thermal/dropout monitoring.

Technical Context

The LP3982ILD-1.8 employs a PMOS pass transistor architecture enabling ultra-low dropout and near-zero drive current consumption-unlike PNP-based LDOs. Its internal bandgap reference and error amplifier provide precise regulation with fast 120µs turn-on time and 60dB PSRR at 1kHz.

It integrates fault detection via an open-drain FAULT pin that asserts low during thermal shutdown, current limit, or input-to-output differential approaching dropout. The device remains stable under no-load conditions and supports noise reduction via a dedicated 33nF bypass capacitor on the reference node.

Key Specifications

Pinout & Package

LP3982ILD-1.8 is housed in an 8-pin LLP (Leadless Leadframe Package), measuring 3.0mm × 3.0mm × 0.8mm, with wettable flanks for automated optical inspection. This thermally enhanced surface-mount package provides lower θ_JA than MSOP-8 when properly laid out with thermal vias and copper planes.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with MAX8860EUB18+T, LP3982ILD-1.8 omits reverse-battery protection but matches all regulation specs and FAULT functionality; versus TPL720F18-DBVR, it delivers 50% higher current and adds fault signaling at the cost of slightly larger footprint and higher IQ.

Availability

LP3982ILD-1.8 is available at Aetrix Electronics and suitable for wireless handsets, DSP core power supplies, and portable medical sensors requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LP3982ILD-1.8 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments acquired National Semiconductor in 2011 and maintains its precision analog portfolio, including high-performance LDOs and power management ICs for portable and industrial applications.

The LP3982 series was designed specifically for battery-powered systems demanding micropower operation, ultra-low dropout, and low-noise regulation - targeting handheld communications, portable instrumentation, and always-on sensing nodes.

FAQ

What is the maximum input voltage rating for LP3982ILD-1.8?

The absolute maximum input voltage for LP3982ILD-1.8 is 6.5V, but the recommended operating range is 2.5V to 6.0V. Exceeding 6.5V risks permanent damage. Within the operating range, the device maintains 1.8V output regulation with 120mV typical dropout at full 300mA load. Always include input transient protection if used in environments with voltage spikes.

Does LP3982ILD-1.8 require an external bypass capacitor, and if so, what value?

Yes, LP3982ILD-1.8 requires a 33nF NPO or COG ceramic capacitor between Pin 6 (CC) and ground to achieve its specified 37µV RMS output noise. This capacitor filters the internal bandgap reference and does not affect transient response-but reduces turn-on time if undersized. Polypropylene film capacitors may be used for lower leakage, though ceramic is standard and sufficient.

Can LP3982ILD-1.8 be used with ceramic output capacitors smaller than 10µF?

Yes, LP3982ILD-1.8 is explicitly designed for stability with ceramic output capacitors as small as 2.2µF - a key advantage over older LDOs requiring higher ESR tantalum types. Using 2.2µF X5R or X7R ceramics saves board space and cost while providing effective high-frequency noise filtering. Avoid Z5U/Y5V dielectrics due to severe capacitance drift over temperature.

How does the FAULT pin on LP3982ILD-1.8 function, and what conditions trigger it?

The FAULT pin on LP3982ILD-1.8 is an open-drain output that pulls low during three conditions: thermal shutdown (>160°C junction), output current limiting (~330–770mA), or input-to-output differential falling within ~120–280mV of dropout. It requires a pull-up resistor (typically 100kΩ) and enables system-level fault detection without additional monitoring circuitry - a feature absent in many competing 1.8V LDOs.

Is LP3982ILD-1.8 pin-compatible with other regulators in the LP3982 family?

Yes, all LP3982 variants-including LP3982ILD-1.8, LP3982ILD-2.5, and LP3982ILD-ADJ-share identical 8-pin LLP pinouts and package dimensions (LDA08C). This allows design reuse across voltage options and simplifies BOM management. Fixed-output versions internally disconnect the SET pin, making them electrically and mechanically interchangeable where voltage requirements change.