Texas Instruments LP3982ILD-3.3

Overview

LP3982ILD-3.3 from Texas Instruments (formerly National Semiconductor) is a fixed-output 3.3V, 300mA micropower ultra-low-dropout CMOS linear regulator in an 8-pin LLP package. It features 120mV typical dropout at full load, 90µA typical quiescent current, 1nA shutdown current, ±2% output voltage tolerance, and 37µV_RMS output noise (10Hz–100kHz). It powers DSP cores and wireless handset baseband circuits where battery life and low-noise supply stability are critical.

For engineers reviewing the LP3982ILD-3.3 datasheet, LP3982ILD-3.3 pinout, LP3982ILD-3.3 application, or LP3982ILD-3.3 equivalent, key selection criteria include dropout performance at 300mA, ceramic capacitor compatibility (≥2.2µF), FAULT pin behavior under regulation loss, thermal shutdown threshold (160°C), and MSOP/LLP package interchangeability with MAX8860.

Technical Context

The LP3982ILD-3.3 uses a PMOS pass transistor architecture enabling true ultra-low dropout operation without PNP drive current overhead. Its internal zero compensates for low-ESR ceramic capacitors down to 2.2µF, ensuring stability across temperature and load without external compensation components.

It integrates a 1.25V bandgap reference, error amplifier, overcurrent limiting, thermal shutdown (160°C with 10°C hysteresis), and open-drain FAULT output that asserts low during dropout, current limit, or thermal fault. The SHDN pin supports logic-level control with 0.4V max V_IL and 2V min V_IH.

Key Specifications

Pinout & Package

LP3982ILD-3.3 is housed in an 8-pin LLP (Leadless Leadframe Package), 3mm × 3mm, 0.5mm pitch, thermally enhanced surface-mount package with exposed thermal pad. This package delivers θ_JA ≈ 163°C/W with 500 LFPM airflow and supports high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LP3982ILD-3.3, MAX8860EUB33+T offers identical form-factor but omits fault reporting, while TPL7407LDR trades dropout performance for lower IQ-making LP3982ILD-3.3 the optimal balance of low-noise, low-dropout, and integrated fault awareness in space-constrained portable designs.

Availability

LP3982ILD-3.3 is available at Aetrix Electronics and suitable for wireless handsets, DSP core supplies, and battery-powered IoT sensor nodes requiring stable component supply across production lifecycles.

Supply support for LP3982ILD-3.3 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 and power management portfolio. TI is a global semiconductor leader focused on analog, embedded processing, and connectivity solutions.

The LP3982ILD-3.3 belongs to National Semiconductor's micropower LDO family, engineered specifically for battery-critical portable electronics demanding ultra-low IQ, low noise, and robust fault protection in minimal footprint packages.

FAQ

What is the minimum input voltage required for LP3982ILD-3.3 to regulate 3.3V output at 300mA?

The LP3982ILD-3.3 requires a minimum input voltage of 3.42V (3.3V + 120mV typical dropout) to maintain regulation at 300mA load. Its specified input range starts at 2.5V, but below 3.42V it enters dropout mode and output voltage drops linearly with input. Designers should ensure battery voltage remains above this threshold during discharge to sustain full 3.3V operation.

Does LP3982ILD-3.3 require an external bypass capacitor on the CC pin, and what value is recommended?

Yes, LP3982ILD-3.3 requires a 33nF NPO or COG ceramic capacitor between pin 6 (CC) and ground to minimize output voltage noise. This capacitor connects directly to the internal bandgap reference and reduces broadband noise to 37µV_RMS. Using lower values speeds up start-up time; higher values increase noise suppression but extend turn-on delay. Film capacitors (e.g., polypropylene) may be used for ultra-low leakage, though ceramic is standard.

Can LP3982ILD-3.3 be used with only ceramic capacitors, and what is the minimum recommended output capacitance?

Yes, LP3982ILD-3.3 is explicitly designed for ceramic output capacitors as low as 2.2µF. It incorporates internal compensation to remain stable with low-ESR ceramics-eliminating the need for higher-ESR tantalum or aluminum electrolytic types. X5R or X7R dielectrics are preferred for temperature stability; Z5U/Y5V types are discouraged due to >50% capacitance loss over temperature.

How does the FAULT pin on LP3982ILD-3.3 behave during thermal shutdown or current limit events?

The FAULT pin on LP3982ILD-3.3 is an open-drain output that pulls low during three conditions: (1) input-to-output differential falls below the tracked dropout threshold, (2) output current exceeds current limit (~330–770mA), or (3) junction temperature reaches 160°C triggering thermal shutdown. It remains low until all fault conditions clear and the regulator re-stabilizes. An external pull-up resistor (e.g., 100kΩ) is mandatory for proper logic-level signaling.

Is LP3982ILD-3.3 pin-compatible with other packages in the LP3982 family, such as the MSOP version?

Yes, LP3982ILD-3.3 (LLP-8) shares identical pinout and electrical functionality with LP3982IMM-3.3 (MSOP-8), including VIN, GND, VOUT×2, FAULT, SHDN, CC, and EPAD/GND mapping. Both are also pin- and package-compatible with Maxim MAX8860. However, thermal performance differs: LLP offers better θ_JA with proper PCB layout, while MSOP has higher 223°C/W rating without airflow.