Texas Instruments LP2985A-18DBVRG4

Overview

LP2985A-18DBVRG4 from Texas Instruments is a fixed 1.8V, 150mA low-dropout linear regulator in SOT-23-5 (DBV) package, featuring ±0.5% output accuracy (new chip), 30µVRMS output noise with 10nF bypass capacitor, and 70dB PSRR at 1kHz - designed for powering noise-sensitive analog circuits and low-voltage microcontrollers in motor control and wireless infrastructure.

For engineers reviewing the LP2985A-18DBVRG4 datasheet, LP2985A-18DBVRG4 pinout, LP2985A-18DBVRG4 application, or LP2985A-18DBVRG4 equivalent, key selection criteria include dropout voltage at 150mA (≤198mV), shutdown current (1.12µA typ), stability with 2.2µF ceramic output capacitors, and thermal shutdown threshold (170°C).

Technical Context

The LP2985A-18DBVRG4 implements a CMOS-based LDO architecture with internal bandgap reference, error amplifier, and P-channel pass transistor. Its enable logic uses an active-high ON/OFF pin with 0.15V low-threshold and 1.6V high-threshold, supporting direct tie-to-VIN operation when unused.

It integrates UVLO (2.2–2.4V rising), thermal shutdown (170°C trip, 150°C reset), overcurrent protection, and internal soft-start to limit inrush current. The BYPASS pin connects to a 10nF capacitor to reduce reference noise, enabling ultra-low-noise regulation critical for RF and precision ADC supply rails.

Key Specifications

Pinout & Package

LP2985A-18DBVRG4 is housed in a 5-pin SOT-23 (DBV) package measuring 2.9mm × 2.8mm, optimized for space-constrained PCB layouts and thermal performance (R_θJA = 178.6°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPL72018PDQNR and MCP1700T-1802E/TT, the LP2985A-18DBVRG4 uniquely combines 30µVRMS noise, 70dB PSRR at 1kHz, and BYPASS-pin-enabled noise optimization - making it the only option among the three qualified for RF and high-resolution data converter applications.

Availability

LP2985A-18DBVRG4 is available at Aetrix Electronics and suitable for motor drives, active antenna systems, cordless power tools, and land mobile radio designs requiring stable component supply, long-term manufacturability, and guaranteed traceability.

Supply support for LP2985A-18DBVRG4 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 delivering analog and embedded processing solutions, with decades of expertise in power management IC design and automotive-grade reliability validation.

The LP2985A series belongs to TI's precision low-noise LDO portfolio, engineered specifically for noise-critical applications in industrial automation, wireless infrastructure, and portable electronics where clean, stable voltage rails are essential.

FAQ

What is the output voltage tolerance of the LP2985A-18DBVRG4 across temperature and load?

The LP2985A-18DBVRG4 guarantees ±0.5% output voltage accuracy over full load (1mA–150mA) and temperature (–40°C to +125°C). This tight tolerance ensures reliable operation of 1.8V I/O interfaces and core logic in microcontrollers without external trimming or calibration.

Can the LP2985A-18DBVRG4 operate with a 2.0V input supply?

No - the LP2985A-18DBVRG4 requires a minimum input voltage of 2.5V per its recommended operating conditions. At 150mA load, its maximum dropout is 198mV, so the lowest functional input is 1.998V; however, 2.5V is the absolute minimum specified for guaranteed regulation and protection feature operation.

What capacitor value is required on the BYPASS pin of the LP2985A-18DBVRG4?

The LP2985A-18DBVRG4 requires a 10nF ceramic capacitor between the BYPASS pin and GND to achieve its specified 30µVRMS output noise. Using smaller values (e.g., 100pF or 1nF) increases noise density, while larger values provide diminishing returns and may affect transient response.

Is the LP2985A-18DBVRG4 stable with a 1µF output capacitor?

No - the LP2985A-18DBVRG4 requires a minimum 2.2µF ceramic output capacitor for guaranteed stability. While the datasheet notes a nominal 1µF minimum effective capacitance (after 50% derating), the 2.2µF nominal value ensures margin across voltage, temperature, and manufacturer tolerances.

Does the LP2985A-18DBVRG4 include thermal shutdown protection?

Yes - the LP2985A-18DBVRG4 incorporates thermal shutdown that activates at 170°C junction temperature and resets at 150°C. This protection is fully integrated and requires no external components, safeguarding the device during overload or poor heatsinking conditions.