STMicroelectronics LD2982BM285R

Overview

LD2982BM285R from STMicroelectronics is a 50 mA fixed-output low-dropout linear voltage regulator delivering 2.85 V with ±1% tolerance at 25 °C, featuring 120 mV dropout at 50 mA, 30 µV_RMS output noise (with 10 nF bypass capacitor), and TTL-compatible inhibit control on Pin 3. It operates across –40 °C to 125 °C and supports stable regulation with only 1 µF ceramic output capacitance - ideal for space-constrained, low-noise battery-powered systems such as portable audio and imaging modules.

For engineers reviewing the LD2982BM285R datasheet, LD2982BM285R pinout, LD2982BM285R application, or LD2982BM285R equivalent, key selection criteria include ultra-low quiescent current (<1 µA in shutdown), low-ESR capacitor compatibility, precise 2.85 V output stability over temperature and load, and SOT23-5L package integration into high-density PCB layouts.

Technical Context

The LD2982BM285R employs a PNP pass transistor architecture enabling ultra-low dropout (7 mV at 1 mA, 120 mV at 50 mA) and minimal quiescent current (75 µA at 1 mA, 375 µA at 50 mA). Its internal feedback network sets a fixed 2.85 V output, trimmed to ±1% at 25 °C and maintaining ±2.5% over –40 °C to 125 °C.

Logic-controlled inhibit functionality (Pin 3) enables full shutdown with <1 µA supply current when pulled low; the pin is not internally biased and must not float. A dedicated bypass pin (Pin 4) accepts a 10 nF capacitor to ground, reducing broadband output noise to 30 µV_RMS (300 Hz–50 kHz).

Key Specifications

Pinout & Package

LD2982BM285R is housed in a compact, surface-mount SOT23-5L package (2.8 × 1.6 × 1.3 mm), optimized for thermal performance (R_thJA = 255 °C/W) and automated assembly. The 5-pin configuration supports input, ground, logic inhibit, bypass, and regulated output connections with no external biasing required.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP2112K-2.85TRG1 and TCS2102-2850DBVR, LD2982BM285R uniquely combines sub-µA inhibit shutdown, 30 µV_RMS noise via bypass pin, and 120 mV dropout - making it optimal for battery-critical, noise-sensitive, and power-gated embedded systems.

Availability

LD2982BM285R is available at Aetrix Electronics and suitable for portable imaging modules, wearable biometric sensors, industrial IoT edge nodes, and smart audio accessories requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LD2982BM285R 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, consumer, and communications markets.

The LD2982 series belongs to ST's precision low-dropout regulator product line, engineered specifically for ultra-low-noise, ultra-low-power applications in portable and battery-operated equipment where efficiency, size, and signal integrity are critical.

FAQ

What is the minimum input voltage required for LD2982BM285R to maintain 2.85 V output at 50 mA?

The dropout voltage is 120 mV at 50 mA, so the minimum input voltage is 2.85 V + 0.12 V = 2.97 V. Operation below this level results in unregulated output. Input must also remain ≥2.5 V per absolute maximum ratings, but regulation is only guaranteed above the dropout threshold.

Can LD2982BM285R operate without the 10 nF bypass capacitor on Pin 4?

Yes - the device functions without the bypass capacitor, but output noise increases from 30 µV_RMS to approximately 80–100 µV_RMS. The bypass cap is optional for noise-critical applications; omitting it does not affect regulation, stability, or basic functionality.

Is the INHIBIT pin internally pulled up or pulled down?

No - the INHIBIT pin has no internal pull-up or pull-down. It must never be left floating. When unused, ST recommends tying it directly to the IN pin to ensure permanent enable. Driving it below 0.15 V disables the regulator; driving it above 2 V enables it.

What output capacitor value is required for stable operation at 2.85 V output?

Per ST's application note, a minimum 2.2 µF low-ESR ceramic capacitor is required for output voltages between 1.8 V and 3.3 V - which includes 2.85 V. Using less than 2.2 µF risks instability unless a series resistor is added to emulate ESR, per Section 6.3 of the datasheet.