Texas Instruments LP2985A-33DBVRE4

Overview

LP2985A-33DBVRE4 from Texas Instruments is a fixed-output, low-noise, low-dropout linear regulator delivering 3.3 V at up to 150 mA with ±1% output tolerance (A-grade), 280 mV typical dropout at full load, and 30 μV_RMS output noise using a 10-nF bypass capacitor. It integrates active-low shutdown, overcurrent and thermal protection, and operates from 2.2 V to 16 V input - ideal for powering precision analog circuitry in space-constrained portable systems.

For engineers reviewing the LP2985A-33DBVRE4 datasheet, LP2985A-33DBVRE4 pinout, LP2985A-33DBVRE4 application, or LP2985A-33DBVRE4 equivalent, key selection criteria include its ultra-low dropout performance across temperature, shutdown current of 0.01 μA, compatibility with ceramic output capacitors ≥2.2 μF, and SOT-23 (DBV) 5-pin package footprint.

Technical Context

The LP2985A-33DBVRE4 uses a PNP pass transistor architecture enabling ultra-low dropout voltage - 7 mV at 1 mA and 280 mV at 150 mA - while maintaining stability with low-ESR ceramic capacitors. Its internal bandgap reference is buffered via the dedicated BYPASS pin to minimize noise coupling.

Shutdown is implemented through an active-low ON/OFF pin requiring ≤0.3 V for disable and ≥1.6 V for enable; unconnected operation is prohibited. Protection includes foldback current limiting and thermal shutdown with automatic recovery, ensuring robustness under fault conditions without external components.

Key Specifications

Pinout & Package

SOT-23 (DBV) 5-pin plastic package, 2.90 mm × 1.60 mm body size, surface-mountable with standard reflow profile (MSL Level-1).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-3.302E/TT and AP2204K-3.3TRG1, the LP2985A-33DBVRE4 uniquely combines ±1% A-grade accuracy, 280 mV dropout, and 30 μV_RMS noise via external BYPASS control - making it irreplaceable in noise-sensitive, battery-constrained applications demanding precision regulation.

Availability

LP2985A-33DBVRE4 is available at Aetrix Electronics and suitable for portable medical sensors, Bluetooth Low Energy modules, digital camera image signal chains, and industrial PLC I/O conditioning requiring stable component supply with guaranteed long-term sourcing.

Supply support for LP2985A-33DBVRE4 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 leader specializing in analog and embedded processing technologies, with decades of expertise in power management IC design and manufacturing.

The LP2985 family was engineered specifically for portable and space-constrained applications requiring ultra-low dropout, low noise, and shutdown capability - targeting battery-powered consumer, medical, and industrial devices.

FAQ

What is the maximum input voltage rating for the LP2985A-33DBVRE4?

The LP2985A-33DBVRE4 has an absolute maximum input voltage of 16 V, with recommended operating range from 2.2 V to 16 V. Exceeding 16 V risks permanent damage per Absolute Maximum Ratings. The 2.2 V lower limit ensures proper regulation given its 280 mV dropout at full load - e.g., 3.58 V minimum input required for 3.3 V output at 150 mA.

Does the LP2985A-33DBVRE4 require an external bypass capacitor for basic operation?

No - the LP2985A-33DBVRE4 functions without the BYPASS capacitor, but omitting the 10-nF ceramic capacitor on the BYPASS pin increases output noise from 30 μV_RMS to ~120 μV_RMS. The BYPASS pin is optional for noise-sensitive applications like precision ADCs or RF synthesizers, but not required for general-purpose 3.3 V regulation.

Can the LP2985A-33DBVRE4 be used with ceramic output capacitors smaller than 2.2 μF?

No - the LP2985A-33DBVRE4 requires a minimum 2.2 μF ceramic output capacitor for stability across temperature and load. Using smaller values risks oscillation or poor transient response. Capacitance may be increased beyond 2.2 μF (e.g., 4.7 μF or 10 μF) to improve load-step immunity, but ESR must remain within 5–300 mΩ per datasheet Figures 18–20.

What happens if the ON/OFF pin of the LP2985A-33DBVRE4 is left floating?

Leaving the ON/OFF pin floating is strictly prohibited - it causes undefined behavior including erratic enable/disable cycling or failure to start. TI specifies that the pin must be actively driven: tied to VIN for always-on operation or pulled to GND (≤0.3 V) for shutdown. A pull-up resistor to VIN is acceptable if driven by open-drain logic.

Is the LP2985A-33DBVRE4 RoHS-compliant and lead-free?

Yes - the LP2985A-33DBVRE4 is RoHS-compliant and lead-free, with "Green (RoHS & no Sb/Br)" eco plan and CU NIPDAU lead finish. It meets JEDEC J-STD-020 moisture sensitivity level 1 (260°C, unlimited floor life), and is qualified for operation from –40°C to +125°C junction temperature.