Texas Instruments LP2985A-28DBVRE4

Overview

LP2985A-28DBVRE4 from Texas Instruments is a fixed-output, low-noise, low-dropout linear regulator delivering 150 mA continuous output current at 2.8 V with ±1% output tolerance (A-grade), ultra-low dropout of 280 mV at full load, and shutdown capability consuming only 0.01 µA in OFF state - deployed in portable audio, camera modules, and battery-powered microcontroller subsystems.

For engineers reviewing the LP2985A-28DBVRE4 datasheet, LP2985A-28DBVRE4 pinout, LP2985A-28DBVRE4 application, or LP2985A-28DBVRE4 equivalent, key selection criteria include dropout voltage at 150 mA, 30 µV_RMS noise performance with 10-nF BYPASS capacitor, SOT-23-5 package thermal resistance (206 °C/W), shutdown input logic thresholds, and stability with ceramic output capacitors ≥2.2 µF.

Technical Context

The LP2985A-28DBVRE4 uses a PNP pass transistor architecture enabling ultra-low dropout operation and inherent reverse-input-protection diode behavior. Its bandgap reference is decoupled via the dedicated BYPASS pin to minimize noise coupling into the error amplifier.

It integrates overcurrent and thermal shutdown protection, operates across –40°C to +125°C junction temperature, supports input voltages up to 16 V, and maintains regulation down to VIN = VOUT + 280 mV at 150 mA - with ground current scaling linearly from 850 µA (150 mA load) to 7 µA (no load).

Key Specifications

Pinout & Package

SOT-23-5 (DBV) package: 2.90 mm × 1.60 mm body, surface-mount, lead-free (RoHS-compliant), moisture sensitivity level (MSL) 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-2802E/TT and AP2112K-2.8TRG1, the LP2985A-28DBVRE4 uniquely combines A-grade 1% tolerance, dedicated BYPASS pin for 30-µV_RMS noise, and active-low shutdown in SOT-23-5 - making it optimal for space-constrained, noise-sensitive, battery-operated 2.8-V systems where precision and low IQ are prioritized over raw current capacity.

Availability

LP2985A-28DBVRE4 is available at Aetrix Electronics and suitable for portable digital cameras, Bluetooth audio headsets, and industrial sensor nodes requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LP2985A-28DBVRE4 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 and embedded processing technologies, with leadership in power management ICs and high-reliability industrial components.

The LP2985 family was designed for cost-effective, low-noise, low-dropout regulation in space- and power-constrained portable and industrial applications - emphasizing simplicity, stability with ceramic capacitors, and robust protection features.

FAQ

What is the maximum input voltage rating for the LP2985A-28DBVRE4?

The LP2985A-28DBVRE4 has an absolute maximum input voltage of 16 V. Operation above this risks permanent damage. In normal use, the recommended maximum is 16 V, and minimum input is 2.2 V or VOUT + dropout voltage (2.8 V + 0.28 V = 3.08 V at full load). Always observe derating guidelines per thermal conditions.

Does the LP2985A-28DBVRE4 require an external bypass capacitor for basic operation?

No - the LP2985A-28DBVRE4 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 capacitor is optional for noise-sensitive applications like ADC references or RF circuitry, but not required for general-purpose 2.8-V regulation.

Can the LP2985A-28DBVRE4 be used with ceramic output capacitors?

Yes - the LP2985A-28DBVRE4 is explicitly designed to be stable with low-ESR ceramic capacitors. A minimum 2.2 µF ceramic capacitor is required at the output, and it must maintain that capacitance over the full operating temperature range (–40°C to +125°C). ESR should fall within the range shown in Figure 19 of the datasheet.

What happens if the ON/OFF pin is left floating on the LP2985A-28DBVRE4?

Leaving the ON/OFF pin floating on the LP2985A-28DBVRE4 may cause unpredictable operation - the device could oscillate between ON and OFF states or latch in an undefined state due to noise coupling. TI specifies that the pin must be actively terminated: tie to VIN for always-on operation, or drive with a clean logic signal meeting ≥40 mV/µs slew rate and defined voltage thresholds (≤0.15 V for OFF, ≥1.6 V for ON).

How does the LP2985A-28DBVRE4 handle reverse voltage conditions where VOUT exceeds VIN?

The LP2985A-28DBVRE4 contains an inherent parasitic diode across its PNP pass element (anode at VOUT, cathode at VIN). If VOUT rises above VIN, this diode becomes forward-biased and can trigger destructive SCR latch-up. To prevent this, TI recommends adding an external Schottky diode (anode to VOUT, cathode to VIN) to clamp reverse voltage to ~0.3 V - a mandatory design step in systems with shared rails or hot-swap scenarios.