Texas Instruments LP2985-28DBVRG4

Overview

LP2985-28DBVRG4 from Texas Instruments is a fixed 2.8V, 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. It delivers stable power to noise-sensitive analog circuits and low-voltage microcontrollers in battery-powered industrial systems.

For engineers reviewing the LP2985-28DBVRG4 datasheet, LP2985-28DBVRG4 pinout, LP2985-28DBVRG4 application, or LP2985-28DBVRG4 equivalent, key selection criteria include dropout voltage at 150mA (180–198 mV), shutdown current (1.12 µA typ), thermal shutdown threshold (170°C), stability with 2.2µF ceramic output capacitors, and enable logic thresholds (0.15V low / 1.6V high).

Technical Context

The LP2985-28DBVRG4 uses a CMOS pass transistor architecture with internal bandgap reference and error amplifier, enabling ultra-low dropout and high PSRR across 1kHz–1MHz. Its integrated soft-start reduces inrush current, while internal pulldown discharges VOUT during shutdown.

It operates over –40°C to +125°C junction temperature, supports input voltages from 2.5V to 16V, and maintains ±1% total output accuracy across load (0–150mA) and temperature. The BYPASS pin enables low-noise operation via external 10nF capacitor to ground.

Key Specifications

Pinout & Package

Package: 5-pin SOT-23 (DBV), 2.9mm × 2.8mm footprint, surface-mount, thermally enhanced for PCB heat dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TSS721AIDR and MCP1700T-2802E/TT, the LP2985-28DBVRG4 offers superior noise performance (30µVRMS vs ≥40µVRMS), tighter accuracy (±0.5% vs ±2%), and design flexibility via BYPASS and ON/OFF pins - making it optimal for mixed-signal and battery-constrained systems requiring regulated analog integrity.

Availability

LP2985-28DBVRG4 is available at Aetrix Electronics and suitable for washer/dryer control boards, land mobile radio front-ends, active antenna systems, cordless power tool motor controllers, and motor drives requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for LP2985-28DBVRG4 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 ICs and high-reliability industrial components.

The LP2985 family was designed specifically for low-noise, wide-input LDO applications in portable and industrial equipment, targeting noise-sensitive analog circuits, RF subsystems, and microcontroller power domains where precision, efficiency, and thermal robustness are essential.

FAQ

What is the output voltage tolerance of the LP2985-28DBVRG4 over temperature and load?

The LP2985-28DBVRG4 guarantees ±0.5% initial output voltage accuracy and maintains ±1% total output accuracy across the full operating range of –40°C to +125°C junction temperature and 0–150mA load current. This specification applies to the "new chip" revision referenced in the SLVS522S datasheet, confirming tight regulation for precision analog and digital I/O rails.

Does the LP2985-28DBVRG4 require an external bypass capacitor, and why?

Yes - the LP2985-28DBVRG4 requires a 10nF capacitor between the BYPASS pin and GND to achieve its specified 30µVRMS output noise performance. This capacitor filters the internal bandgap reference voltage, directly reducing output voltage noise. Omitting it degrades noise performance significantly, as confirmed by TI's typical characteristics data (Figures 5-28–5-31).

What is the minimum output capacitance required for stability with the LP2985-28DBVRG4?

The LP2985-28DBVRG4 is stable with a minimum 2.2µF ceramic output capacitor (X5R/X7R), provided its effective capacitance remains ≥1µF after derating (50% nominal). The device supports ESR up to 1Ω; for higher-ESR capacitors, TI recommends adding a 100nF MLCC close to the VOUT pin to ensure phase margin and transient stability.

How does the ON/OFF pin function on the LP2985-28DBVRG4, and what are its voltage thresholds?

The ON/OFF pin is active-high: driving it above 1.6V (min) enables the regulator; pulling it below 0.15V (max) disables it. In shutdown, ground current drops to 1.12µA typical. Unlike legacy versions, the LP2985-28DBVRG4 has no slew rate requirement on this pin and includes an internal pulldown to actively discharge VOUT during disable - critical for safe multi-rail sequencing.

What thermal protection features does the LP2985-28DBVRG4 include?

The LP2985-28DBVRG4 integrates thermal shutdown that activates at 170°C junction temperature (T_SD+) and resets at 150°C (T_SD−). It also includes current limiting with a peak output current of 300–350mA. These protections operate independently of external circuitry and are fully characterized per the SLVS522S datasheet, ensuring safe operation under overload or poor heatsinking conditions.