Texas Instruments LP2981-33DBVRG4

Overview

LP2981-33DBVRG4 from Texas Instruments is a 3.3 V, 100-mA ultra-low dropout linear regulator in SOT-23-5 package with shutdown control, ±1.25% output tolerance (standard grade), 200 mV typical dropout at 100 mA, and 0.01 µA shutdown current - designed for power management in space-constrained portable electronics including digital cameras and PDAs.

For engineers reviewing the LP2981-33DBVRG4 datasheet, LP2981-33DBVRG4 pinout, LP2981-33DBVRG4 application, or LP2981-33DBVRG4 equivalent, key selection criteria include input voltage range (2.2–16 V), thermal protection, ON/OFF logic compatibility, minimum 3.3 µF output capacitance with ESR compliance, and SOT-23-5 PCB footprint constraints.

Technical Context

The LP2981-33DBVRG4 uses a vertical PNP pass element enabling ultra-low dropout (7 mV at 1 mA, 200 mV at 100 mA) and low quiescent current (600 µA typ at full load). Its internal reference is 1.23 V, with feedback resistors R1/R2 set for fixed 3.3 V output.

It integrates overcurrent and thermal shutdown protection, supports fast transient response, and requires active termination of the ON/OFF pin - pulled high to VIN for always-on operation or driven low (<0.3 V) to enter 0.01 µA shutdown mode. Pin 4 (NC) must remain unconnected.

Key Specifications

Pinout & Package

SOT-23-5 (DBV) package: 2.92 mm × 1.6 mm × 1.1 mm body, surface-mount, RoHS-compliant, moisture sensitivity level 1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LP2981-33DBVR, LP2981-33DBVRG4 offers identical performance with enhanced environmental compliance (Sb/Br-free), while MCP1700T-3302E/TT trades away shutdown functionality for lower quiescent current - making LP2981-33DBVRG4 optimal for systems requiring programmable power gating in portable designs.

Availability

LP2981-33DBVRG4 is available at Aetrix Electronics and suitable for mobile phones, digital cameras, PDAs, and MP3 players requiring stable component supply with guaranteed long-term sourcing and RoHS-compliant green packaging.

Supply support for LP2981-33DBVRG4 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 specializing in analog, embedded processing, and connectivity technologies, serving industrial, automotive, and consumer markets.

The LP2981 family was designed as cost-effective, ultra-low-dropout regulators for portable electronics - emphasizing small footprint, low IQ, and robust protection in SOT-23 packages.

FAQ

What is the output voltage tolerance of LP2981-33DBVRG4 across temperature?

The LP2981-33DBVRG4 has a standard-grade output voltage tolerance of ±1.25% over the full operating junction temperature range of –40°C to 125°C. At 25°C, the tolerance is tighter at ±1.0%, and the device maintains this specification under load currents from 1 mA to 100 mA. This ensures reliable 3.3 V rail accuracy for microcontrollers and sensors in demanding thermal environments.

Can LP2981-33DBVRG4 be used with ceramic output capacitors?

LP2981-33DBVRG4 is not stable with typical low-ESR ceramic capacitors alone. It requires an output capacitor with minimum 3.3 µF capacitance and a specific ESR range (e.g., 0.1–1 Ω depending on load). If using ceramics, a 1 Ω series resistor must be added to meet ESR requirements - otherwise, oscillation or poor transient response may occur.

What is the minimum input voltage required for LP2981-33DBVRG4 to regulate properly?

The LP2981-33DBVRG4 requires a minimum input voltage of 2.2 V to properly bias its internal control circuitry - even though its dropout is as low as 7 mV at light loads. For reliable 3.3 V output, VIN must be ≥3.3 V + dropout voltage (e.g., ≥3.5 V at 100 mA), and absolute maximum VIN is 16 V.

How does the ON/OFF pin of LP2981-33DBVRG4 behave during power-up?

The ON/OFF pin of LP2981-33DBVRG4 must be actively terminated: connect to VIN for default-on operation, or drive with a logic signal (≥1.6 V = on, ≤0.3 V = off). During power-up, if left floating, the regulator may power up unpredictably; TI specifies a minimum slew rate of 40 mV/µs for clean transition between states to avoid metastability.

Is LP2981-33DBVRG4 pin-compatible with other LP2981 variants?

Yes - all LP2981 variants in SOT-23-5 (DBV) package, including LP2981-33DBVRG4, LP2981-33DBVR, and LP2981A-33DBVR, share identical pinout (VIN, GND, ON/OFF, NC, VOUT), package dimensions, and thermal characteristics. Only output voltage and grade (A-grade ±0.75% vs. standard ±1.25%) differ between part numbers.