STMicroelectronics LD2982AM25R

Overview

LD2982AM25R from STMicroelectronics is a 50 mA, 2.5 V fixed-output low-dropout (LDO) linear voltage regulator with logic-controlled inhibit function, ultra-low dropout (120 mV at 50 mA), low quiescent current (600–900 µA in active mode, <1 µA in shutdown), and 30 µV_RMS output noise. It operates across –40 °C to +125 °C and supports stable regulation with only 1 µF ceramic output capacitance - ideal for space-constrained, battery-powered portable electronics requiring clean, low-power bias rails.

For engineers reviewing the LD2982AM25R datasheet, LD2982AM25R pinout, LD2982AM25R application, or LD2982AM25R equivalent, this regulator delivers precise 2.5 V output with ±1% tolerance at 25 °C, TTL-compatible inhibit control (pin 3), bypass-pin noise filtering, and SOT23-5L packaging - critical for low-noise analog subsystems, sensor power domains, and standby-aware embedded designs.

Technical Context

The LD2982AM25R integrates a PNP pass transistor enabling ultra-low dropout operation and uses internal feedback resistors (R1 = 42.6 kΩ, R2 = 51.15 kΩ) to set its 2.5 V output. Its inhibit input (pin 3) directly controls the pass element via TTL-level logic: pulling below 0.15 V disables regulation and reduces quiescent current to <1 µA.

No internal reverse-blocking diode exists between IN and OUT; reverse current flows only through feedback resistors (typ. 160 µA when V_REV applied), making it suitable for systems where output-voltage overshoot must not backfeed the input rail. Thermal protection and current limiting are implemented internally.

Key Specifications

Pinout & Package

Supplied in compact SOT23-5L package (2.8 × 1.75 × 1.3 mm, 5-pin surface-mount), optimized for high-density PCB layouts and automated assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP2202K-2.5TRG1 and MCP1702T-2502E/MB, the LD2982AM25R uniquely balances 50 mA capability, <1 µA shutdown, 30 µV_RMS noise with bypass pin, and 120 mV dropout - making it optimal for noise-critical, battery-conscious 2.5 V domains where both precision and power-state agility matter.

Availability

LD2982AM25R is available at Aetrix Electronics and suitable for portable medical sensors, industrial IoT edge nodes, audio codec bias rails, and optical transceiver modules requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.

Supply support for LD2982AM25R 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing silicon solutions for automotive, industrial, and consumer markets since 1987.

The LD2982 series belongs to ST's high-performance analog LDO portfolio, engineered specifically for ultra-low-noise, low-power portable electronics - emphasizing dropout minimization, shutdown efficiency, and capacitor flexibility in miniature packages.

FAQ

What is the minimum input voltage required for LD2982AM25R to maintain 2.5 V output at 50 mA?

The LD2982AM25R requires an input voltage of at least 2.62 V to sustain 2.5 V output at 50 mA load, based on its 120 mV typical dropout voltage. At lower loads (e.g., 1 mA), dropout falls to 7 mV, allowing operation with input as low as 2.507 V. Input must remain within the absolute maximum rating of 16 V.

Can the INHIBIT pin be left unconnected, or does it require external biasing?

The INHIBIT pin must never be left floating. When unused, it must be tied directly to the IN pin to ensure continuous regulation. If actively controlled, it requires a clean logic signal with VIH ≥ 2 V and VIL ≤ 0.15 V across –40 °C to +125 °C; source impedance should be low enough to avoid threshold uncertainty.

Is a bypass capacitor mandatory for LD2982AM25R operation, or only for noise reduction?

A bypass capacitor (10 nF ceramic to GND) on the BYPASS pin is optional for basic regulation but mandatory to achieve the specified 30 µV_RMS output noise. Without it, noise rises significantly - datasheet characterizes noise performance only with this capacitor installed.

Does LD2982AM25R support ceramic output capacitors with zero ESR, such as NP0/C0G types?

Yes - the LD2982AM25R is explicitly designed for ceramic output capacitors, including low-ESR types like X7R and X5R. NP0/C0G ceramics are acceptable but not required; their ultra-low ESR may necessitate series resistance to maintain phase margin, per Section 6.3 of the datasheet.