STMicroelectronics LD2982AM36R

Overview

LD2982AM36R from STMicroelectronics is a 50 mA fixed-output low-dropout linear voltage regulator with 3.6 V output, ultra-low dropout (120 mV at 50 mA), 30 µV_RMS output noise, logic-controlled inhibit function, and SOT23-5L package. It delivers stable power to noise-sensitive analog circuitry in portable battery-powered systems where quiescent current and thermal performance are critical.

For engineers reviewing the LD2982AM36R datasheet, LD2982AM36R pinout, LD2982AM36R application, or LD2982AM36R equivalent, key selection criteria include dropout voltage at light/heavy load, shutdown current (<1 µA), bypass-capacitor–enabled noise reduction, and compatibility with low-ESR ceramic capacitors for stability without external compensation.

Technical Context

The LD2982AM36R uses a PNP pass transistor architecture enabling very low dropout-just 7 mV at 1 mA and 120 mV at 50 mA-while maintaining tight output regulation (±1 % at 25 °C) across –40 °C to 125 °C. Its inhibit pin (Pin 3) accepts TTL-compatible logic levels (V_IL ≤ 0.15 V, V_IH ≥ 2 V) to disable the regulator and reduce quiescent current to <1 µA.

Output noise is minimized via an internal bypass path routed through Pin 4 (BYPASS), where a 10 nF capacitor to GND reduces integrated RMS noise to 30 µV (300 Hz–50 kHz). The device requires only 1 µF ceramic output capacitance for stability when V_OUT ≥ 3.8 V-confirmed by loop-gain analysis in the datasheet-and features internal current and thermal limiting.

Key Specifications

Pinout & Package

Supplied in compact SOT23-5L package (2.8 × 1.6 × 1.3 mm, 5-pin surface-mount), optimized for space-constrained portable designs and compatible with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6219B362MR-G and BD3985FVM-C, the LD2982AM36R uniquely combines ±1 % initial accuracy, sub-120 mV dropout, <1 µA shutdown, and user-tunable 30 µV_RMS noise-making it optimal for high-fidelity portable analog power domains where all four parameters are simultaneously constrained.

Availability

LD2982AM36R is available at Aetrix Electronics and suitable for portable medical devices, wireless sensor nodes, camera modules, and battery-powered audio systems requiring stable component supply with guaranteed long-term traceability.

Supply support for LD2982AM36R 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, ultra-low-I_Q power delivery in space- and energy-constrained portable electronics.

FAQ

What is the minimum input voltage required for regulation at 3.6 V output?

The LD2982AM36R maintains regulation down to an input voltage of 3.72 V at 50 mA load (3.6 V + 120 mV dropout). At lighter loads, dropout falls to 7 mV-so 3.607 V input suffices at 1 mA. Input must remain ≥2.5 V per absolute maximum ratings, but regulation begins only above V_OUT + V_DROP.

Can the BYPASS pin be left unconnected?

No. Leaving Pin 4 (BYPASS) floating degrades noise performance: output noise rises from 30 µV_RMS to ~100 µV_RMS. If noise reduction is not required, connect a 10 nF ceramic capacitor from BYPASS to GND; do not omit or tie to IN/OUT. The pin has no internal pull-up/down.

Is an input capacitor mandatory, and what type is recommended?

Yes-a minimum 1 µF ceramic capacitor is required on the IN pin, placed within 12.7 mm of the device and returned to clean analog GND. X7R or X5R dielectrics are preferred; tantalum or film types are acceptable but less effective at high frequencies. Larger values improve transient response without stability risk.

Does the LD2982AM36R support reverse current protection?

Yes. The internal PNP pass transistor lacks a body diode, so no forward conduction occurs from OUT to IN when V_OUT > V_IN. Reverse current flows only through internal feedback resistors (R1/R2), measured at ~160 µA-low enough to avoid system-level issues in back-powering scenarios.