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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

STMicroelectronics LD2982BM33R

Name: LD2982BM33R
Brand: STMicroelectronics
SKU: LD2982BM33R
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LD2982BM33R

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Package:: SC-74A, SOT-753

Datasheet:: LD2982BM33R.pdf

Description:: IC REG LINEAR 3.3V 50MA SOT23-5

Quantity:: RFQ Add To RFQ list

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Inventory:1,195

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Product details

Overview

LD2982BM33R from STMicroelectronics is a 50 mA fixed-output low-dropout (LDO) linear voltage regulator with 3.3 V output, TTL-compatible inhibit control, and ultra-low noise (30 µV_RMS). It delivers 120 mV dropout at 50 mA load, draws only 75 µA quiescent current at 1 mA load, and operates across –40 °C to +125 °C - ideal for battery-powered portable electronics requiring stable, quiet power rails.

For engineers reviewing the LD2982BM33R datasheet, LD2982BM33R pinout, LD2982BM33R application, or LD2982BM33R equivalent, key selection criteria include its 1 µF ceramic capacitor stability, <1 µA shutdown current, ±1% output tolerance at 25 °C, and SOT23-5L footprint compatibility in space-constrained designs.

Technical Context

The LD2982BM33R integrates a PMOS pass transistor enabling ultra-low dropout (as low as 7 mV at 1 mA), combined with internal current and thermal limiting for robust operation. Its inhibit input (Pin 3) accepts TTL-level logic to disable regulation and reduce quiescent current to <1 µA - critical for system-level power gating.

Low-noise performance is achieved via a dedicated bypass pin (Pin 4) accepting a 10 nF capacitor to ground, reducing output noise to 30 µV_RMS (300 Hz–50 kHz). Supply voltage rejection remains at 45 dB (typ.) at 1 kHz, supporting clean regulation even with noisy input sources.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	3.3 V ±1% at 25 °C - ensures precise rail generation for 3.3 V logic and analog circuitry without external feedback.
Max Output Current	50 mA - sufficient for powering microcontroller I/O banks, sensors, or RF front-end bias circuits.
Dropout Voltage	120 mV at 50 mA - enables regulation from 3.42 V input, extending battery runtime in single-cell Li-ion or dual-cell alkaline systems.
Quiescent Current	75 µA at 1 mA load - minimizes standby power loss in always-on subsystems like real-time clocks or wake-on-event circuits.
Output Noise	30 µV_RMS (300 Hz–50 kHz) with 10 nF bypass cap - meets stringent noise requirements for ADC references and RF synthesizer supplies.
Input Voltage Range	2.5 V to 16 V - supports wide-input applications including automotive accessory rails and industrial 12 V systems.
Shutdown Current	<1 µA when INHIBIT = low - enables deep-sleep modes in portable devices without external MOSFET switches.

Pinout & Package

LD2982BM33R is housed in a compact, surface-mount SOT23-5L package (2.8 × 1.6 × 1.3 mm), optimized for high-density PCB layouts and reflow compatibility.

Pin/Terminal	Circuit Role	Design Meaning
1 (IN)	Regulator input supply	Accepts 2.5–16 V DC; requires ≥1 µF ceramic capacitor placed ≤0.5″ from pin for stability.
2 (GND)	Analog ground reference	Must connect to clean analog ground plane; shared return path for IN, OUT, and Bypass pins.
3 (INHIBIT)	Logic-controlled enable/disable	TTL-compatible input; pulls low (<0.15 V) to disable regulator and reduce IQ to <1 µA.
4 (BYPASS)	Noise reduction node	Connects 10 nF capacitor to GND to lower output noise to 30 µV_RMS; not functional if left open.
5 (OUT)	Regulated 3.3 V output	Delivers up to 50 mA; requires ≥2.2 µF low-ESR ceramic capacitor (X7R) within 0.5″ for stability.

Key Features

Feature	Design Value
Ultra-low dropout	7 mV at 1 mA load - maintains regulation down to near-V_OUT, maximizing usable battery voltage range.
Low-noise architecture	30 µV_RMS output noise with 10 nF bypass cap - eliminates need for post-regulation LC filtering in sensitive analog stages.
Logic-controlled shutdown	<1 µA quiescent current in inhibit mode - enables system-level power sequencing without external FETs or controllers.
Stable with 1 µF ceramic caps	Guaranteed stability using low-cost, small-footprint X7R ceramics - reduces BOM count and board area vs. tantalum alternatives.
Wide temperature operation	–40 °C to +125 °C junction range - qualified for industrial and extended-temperature embedded applications.

Applications

Portable Medical Sensors

Wearable Health Monitors

Use Scenario: Powering low-power ECG/PPG sensor front-ends in disposable patch monitors.

IC Role / Device Role / Timing Role: Local 3.3 V LDO supplying analog signal chain and ultra-low-power MCU.

Use Value: 30 µV_RMS noise ensures minimal interference on µV-level bio-potential measurements.

Use Scenario: Regulating power for Bluetooth LE SoC and optical heart-rate modules in wrist-worn trackers.

IC Role / Device Role / Timing Role: Primary 3.3 V rail generator with dynamic shutdown during sensor idle periods.

Use Value: <1 µA shutdown current extends coin-cell battery life beyond 6 months in intermittent-sampling mode.

Industrial IoT Edge Nodes

Automotive Cabin Controllers

Use Scenario: Providing clean 3.3 V supply to LoRaWAN transceivers and environmental sensors in remote gateways.

IC Role / Device Role / Timing Role: Low-noise, wide-input LDO operating from 12 V vehicle or solar-charged battery rails.

Use Value: 45 dB SVR suppresses switching noise from DC-DC converters upstream, preserving RF link integrity.

Use Scenario: Powering touch controller ICs and LED drivers in non-safety-critical cabin interfaces (e.g., seat controls).

IC Role / Device Role / Timing Role: Secondary 3.3 V regulator enabled/disabled via microcontroller GPIO for subsystem power management.

Use Value: TTL-compatible INHIBIT pin allows direct connection to MCU I/O without level-shifting circuitry.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
AP2204K-3.3TRG1	Higher dropout (250 mV @ 50 mA); no bypass pin; 50 µV_RMS noise.	Lacks low-noise optimization; suitable where noise is less critical than cost.	Prefer when board space permits larger input headroom and noise specs are relaxed.
MCP1700T-3302E/TT	Lower IQ (2 µA typical in shutdown); 250 mV dropout; no inhibit pin - uses EN instead.	Requires pull-up on EN for always-on operation; lacks TTL-compatible inhibit logic.	Choose when ultra-low shutdown IQ is primary requirement and GPIO logic levels differ.

Compared with AP2204K-3.3TRG1 and MCP1700T-3302E/TT, LD2982BM33R uniquely combines sub-100 mV dropout, <1 µA shutdown, and dedicated bypass pin - making it optimal for noise-sensitive, battery-constrained portable systems requiring precise 3.3 V regulation.

Availability

LD2982BM33R is available at Aetrix Electronics and suitable for portable medical sensors, wearable health monitors, industrial IoT edge nodes, and automotive cabin controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LD2982BM33R 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.

The LD2982 series belongs to ST's precision low-noise LDO portfolio, engineered specifically for battery-powered portable electronics demanding ultra-low dropout, minimal quiescent current, and high PSRR in miniature packages.

FAQ

What is the minimum input voltage required for stable 3.3 V output at 50 mA?

The LD2982BM33R requires an input voltage of at least 3.42 V to maintain regulation at 50 mA load, based on its 120 mV typical dropout voltage. Below this threshold, output voltage drops linearly with input; operation below 2.5 V input is not guaranteed per absolute maximum ratings.

Can the INHIBIT pin be left unconnected?

No - the INHIBIT pin must never be left floating. If unused, it must be tied directly to the input voltage (VI) to ensure the regulator remains enabled. Floating the pin risks unpredictable shutdown behavior due to noise coupling or internal leakage paths.

Is an external capacitor required on the BYPASS pin?

Yes - a 10 nF ceramic capacitor between BYPASS (Pin 4) and GND is required to achieve the specified 30 µV_RMS output noise. Omitting it results in higher broadband noise (≈100 µV_RMS), degrading performance in noise-sensitive analog circuits.

What output capacitor value is recommended for 3.3 V operation?

For 3.3 V output, ST specifies a minimum 2.2 µF low-ESR ceramic capacitor (X7R dielectric) on the OUT pin. This value ensures stability across temperature and load; smaller values may require a series resistor to maintain phase margin, per Section 6.3 of the datasheet.

LD2982BM33R Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: SC-74A, SOT-753

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Output Configuration:: Positive

Output Type:: Fixed

Number of Regulators:: 1

Voltage - Input (Max):: 16V

Voltage - Output (Min/Fixed):: 3.3V

Voltage - Output (Max):: -

Voltage Dropout (Max):: 0.225V @ 50mA

Current - Output:: 50mA

Current - Quiescent (Iq):: 150 µA

Current - Supply (Max):: 1.2 mA

PSRR:: 45dB (1kHz)

Control Features:: Enable

Protection Features:: Over Current, Over Temperature

Operating Temperature:: -40°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-5

LD2982BM33R FAQ

1.How can I place an order for LD2982BM33R through Aetrix?

Please submit a Request for Quotation (RFQ) for LD2982BM33R on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for LD2982BM33R reliable?

The price and inventory of LD2982BM33R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LD2982BM33R is usually 5 days.

3.What payment methods are accepted for LD2982BM33R?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LD2982BM33R transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LD2982BM33R?

LD2982BM33R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LD2982BM33R order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for LD2982BM33R?

For technical support, including LD2982BM33R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LD2982BM33R requirements.

6.How does Aetrix verify that LD2982BM33R is sourced from the original manufacturer or authorized distributors?

All LD2982BM33R products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LD2982BM33R meets industry standards.

7.What is the process for return or replacement of LD2982BM33R?

All LD2982BM33R units undergo pre-shipment inspection (PSI). If there is an issue with LD2982BM33R, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The LD2982BM33R part is unused and in its original packaging.

Return procedure for LD2982BM33R:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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