Texas Instruments LP2981A-33DBVRG4

Overview

LP2981A-33DBVRG4 from Texas Instruments is a 3.3 V, 100-mA ultra-low dropout linear regulator in SOT-23-5 package, featuring ±0.75% output voltage tolerance (A-grade), 200 mV typical dropout at 100 mA, 600 µA typical ground current, and active-low shutdown with 0.01 µA off-state current. It delivers stable power to noise-sensitive analog circuitry in space-constrained portable systems.

For engineers reviewing the LP2981A-33DBVRG4 datasheet, LP2981A-33DBVRG4 pinout, LP2981A-33DBVRG4 application, or LP2981A-33DBVRG4 equivalent, key selection criteria include dropout performance at light-to-full load, shutdown leakage, thermal stability over −40°C to 125°C, and compatibility with low-ESR tantalum or ceramic+series-resistor output capacitors.

Technical Context

The LP2981A-33DBVRG4 uses a vertical PNP pass transistor architecture enabling ultra-low dropout (7 mV at 1 mA, 200 mV at 100 mA) and low quiescent current (65 µA at 1 mA, 600 µA at 100 mA). Its internal reference is trimmed to 1.23 V, feeding an error amplifier that controls the pass element via feedback from R1/R2-though for fixed-output variants like LP2981A-33DBVRG4, this network is internal and non-accessible.

It integrates overcurrent and thermal shutdown protection with foldback current limiting, and features reverse-input-protection awareness requiring external Schottky diode if VOUT may exceed VIN. The ON/OFF pin accepts logic-level signals up to 16 V with defined thresholds: ≤0.15 V (OFF) and ≥1.4 V (ON) across full temperature range.

Key Specifications

Pinout & Package

SOT-23-5 (DBV) package: 2.90 mm × 1.60 mm body, 0.95 mm max height, surface-mount, lead-free and RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout regulator applications.

Compared with LP2981-33DBVR and MCP1700T-3302E/TT, the LP2981A-33DBVRG4 uniquely balances A-grade accuracy, ultra-low dropout, and nanoampere shutdown - making it optimal for battery-powered precision analog systems where all three parameters are simultaneously critical.

Availability

LP2981A-33DBVRG4 is available at Aetrix Electronics and suitable for smart metering, motor control feedback, portable audio, and industrial IoT sensor node designs requiring stable component supply, long-term lifecycle support, and guaranteed A-grade parametric compliance.

Supply support for LP2981A-33DBVRG4 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 is a global semiconductor company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.

The LP2981A family was designed specifically for ultra-low-power, space-constrained portable and industrial applications requiring high-accuracy, low-noise, and thermally robust linear regulation - with emphasis on battery longevity and signal integrity.

FAQ

What is the maximum input voltage rating for the LP2981A-33DBVRG4?

The LP2981A-33DBVRG4 has an absolute maximum input voltage (VIN) rating of 16 V. Operation above this level risks permanent damage. For reliable continuous operation, TI specifies a recommended maximum VIN of 16 V under all conditions, with minimum VIN of 2.2 V required to bias internal circuitry properly.

Does the LP2981A-33DBVRG4 require an external resistor divider for output voltage setting?

No - the LP2981A-33DBVRG4 is a fixed-output device with internal feedback network trimmed to deliver 3.3 V. Unlike adjustable LDOs, it contains no external R1/R2 connections; pins 1–5 are fully dedicated to VIN, GND, ON/OFF, NC, and VOUT respectively.

Can ceramic capacitors be used for COUT with the LP2981A-33DBVRG4?

Yes, but only with a series resistor: ceramic capacitors have very low ESR (often <20 mΩ), which violates LP2981A-33DBVRG4 stability requirements. A 1 Ω resistor must be placed in series with the ceramic output capacitor to raise effective ESR into the 1–5 Ω range required for 100 mA load.

What happens if the ON/OFF pin is left floating on the LP2981A-33DBVRG4?

Leaving the ON/OFF pin floating is undefined and unsafe. The LP2981A-33DBVRG4 may power up unpredictably or oscillate. TI mandates active termination: connect ON/OFF directly to VIN if shutdown is unused - no external pull-up resistor is needed, as the internal structure ensures reliable enable.

Is the LP2981A-33DBVRG4 protected against reverse input-output voltage conditions?

The LP2981A-33DBVRG4 contains an inherent PNP base-emitter diode that becomes forward-biased if VOUT exceeds VIN by ~0.7 V, risking latch-up and damage. TI explicitly requires an external Schottky diode (anode to VOUT, cathode to VIN) in any application where output voltage could rise above input - such as during hot-swap or backup-supply scenarios.