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

STMicroelectronics LD2982BM40R

Name: LD2982BM40R
Brand: STMicroelectronics
SKU: LD2982BM40R
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LD2982BM40R

Manufacturer:: STMicroelectronics

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

Package:: SC-74A, SOT-753

Datasheet:: LD2982BM40R.pdf

Description:: IC REG LINEAR 4V 50MA SOT23-5

Quantity:: RFQ Add To RFQ list

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Inventory:3,056

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Product details

Overview

LD2982BM40R from STMicroelectronics is a 50 mA fixed-output low-dropout linear voltage regulator with 1.8 V output, 120 mV dropout at 50 mA, 30 µV_RMS output noise, logic-controlled inhibit function (TTL-compatible), and SOT23-5L package. It delivers ultra-low quiescent current (75 µA at 1 mA load) and supports battery-powered portable electronics requiring stable, low-noise local regulation.

For engineers reviewing the LD2982BM40R datasheet, LD2982BM40R pinout, LD2982BM40R application, or LD2982BM40R equivalent, key selection criteria include dropout performance at light load, shutdown current (<1 µA), bypass-capacitor–enabled noise reduction, and compatibility with low-ESR ceramic capacitors in space-constrained designs.

Technical Context

The LD2982BM40R integrates a PNP pass transistor enabling ultra-low dropout (7 mV at 1 mA), with internal current and thermal limiting for robust operation. Its inhibit input (Pin 3) provides TTL-compatible enable/disable control, allowing system-level power gating without external circuitry.

Output noise is actively suppressed via a dedicated Bypass pin (Pin 4), where a 10 nF capacitor to GND reduces RMS noise to 30 µV across 300 Hz–50 kHz. The regulator maintains stability with only 1 µF ceramic output capacitance for ≥3.8 V versions - but requires 2.2 µF for the 1.8 V variant per ST's application guidance.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	1.8 V ±1 % at 25 °C; tight tolerance ensures reliable core voltage for 1.8 V I/O domains in portable SoCs.
Dropout Voltage	120 mV at 50 mA load; enables regulation from 1.92 V input, critical for single-cell Li-ion or Li-poly backup rails.
Quiescent Current	75 µA at 1 mA load; supports >1-year battery life in always-on sensor nodes with periodic wake-up.
Output Noise	30 µV_RMS (300 Hz–50 kHz, 10 nF bypass); meets low-noise analog supply requirements for ADCs, RF front-ends, and audio codecs.
Shutdown Current	<1 µA when INHIBIT = LOW; enables deep-sleep mode for system-level power optimization in handheld devices.
Input Voltage Range	2.5 V to 16 V; accommodates wide-input industrial and automotive auxiliary rails while supporting low-voltage battery operation.
Thermal Range	−40 °C to +125 °C junction temperature; qualified for extended-temperature embedded applications including automotive infotainment modules.

Pinout & Package

Supplied in compact SOT23-5L package (2.8 × 1.6 × 1.3 mm), optimized for high-density PCB layouts and automated assembly.

Pin/Terminal	Circuit Role	Design Meaning
1 (IN)	Input supply connection	Accepts 2.5–16 V DC; requires ≤0.5″ placement of 1 µF input capacitor to clean high-frequency ripple.
2 (GND)	Ground reference	Analog ground return path; must be routed separately from digital ground to preserve noise performance.
3 (INHIBIT)	Logic-enable control input	TTL-compatible; pulls LOW (<0.15 V) to disable regulator and reduce IQ to <1 µA; must not float.
4 (BYPASS)	Noise-reduction terminal	Connects 10 nF capacitor to GND to shunt internal reference noise, lowering output noise to 30 µV_RMS.
5 (OUT)	Regulated output	Delivers 1.8 V ±1 %; requires 2.2 µF low-ESR ceramic capacitor placed ≤0.5″ away for stability per ST spec.

Key Features

Feature	Design Value
Ultra-low dropout	7 mV at 1 mA load enables operation from near-threshold battery voltages without brownout.
Sub-µA shutdown	Inhibit-driven deep-off state draws <1 µA, extending shelf life and standby time in IoT edge sensors.
Dedicated noise bypass	Separate BYPASS pin allows targeted 10 nF capacitor placement, reducing output noise by >50 % vs. standard LDOs.
Low-ESR ceramic support	Stable with 2.2 µF X7R ceramic output cap - eliminates need for larger, costlier tantalum or polymer types.
Internal protection	Integrated current limit and thermal shutdown prevent damage during overload or poor heatsinking in SOT23-5L.

Applications

Mobile Baseband Power

Wearable Sensor Hub

Use Scenario: Local 1.8 V supply for cellular modem baseband processor I/O banks in smartphones.

IC Role / Device Role / Timing Role: Low-noise post-regulator delivering clean voltage to high-speed digital interfaces (e.g., MIPI D-PHY).

Use Value: 30 µV_RMS noise prevents bit errors in high-data-rate serial links; 120 mV dropout preserves headroom during battery sag.

Use Scenario: Always-on power rail for MEMS accelerometer, gyroscope, and BLE radio in fitness trackers.

IC Role / Device Role / Timing Role: Primary LDO supplying mixed-signal sensor hub with dynamic enable/disable via host MCU GPIO.

Use Value: 75 µA quiescent current and <1 µA shutdown extend coin-cell battery life beyond 6 months; SOT23-5L saves board area.

Industrial HMI Display

Medical Point-of-Care Monitor

Use Scenario: 1.8 V rail for LCD controller and touch controller ICs in factory-floor HMIs operating at −40 °C to +85 °C.

IC Role / Device Role / Timing Role: Temperature-stable local regulator ensuring consistent display timing and touch response across ambient extremes.

Use Value: ±1 % output tolerance and −40 °C to +125 °C rating guarantee pixel integrity and touch accuracy without recalibration.

Use Scenario: Powering low-power ECG front-end amplifier and microcontroller in portable patient monitors.

IC Role / Device Role / Timing Role: Ultra-low-noise analog supply isolating sensitive biopotential measurement circuitry from digital switching noise.

Use Value: 30 µV_RMS noise floor enables sub-µV ECG signal resolution; internal thermal protection safeguards against enclosure overheating.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
Torex XC6206P182MR	1.8 V, 100 mA, 120 mV dropout, no inhibit pin, 40 µV_RMS noise, SOT23-3	Lacks shutdown control and bypass pin; limited to always-on use cases	Select when board space is constrained and system-level power gating is handled externally.
Richtek RT9013-18GB	1.8 V, 500 mA, 250 mV dropout, enable pin, 45 µV_RMS noise, SOT23-5	Higher current and dropout; higher noise; same pinout but different enable threshold (1.2 V)	Choose when higher load current is needed and 45 µV_RMS noise is acceptable for digital-only loads.

Compared with XC6206P182MR and RT9013-18GB, the LD2982BM40R uniquely combines sub-µA shutdown, dedicated noise-bypass capability, and 1.8 V/50 mA delivery in SOT23-5L - making it optimal for battery-sensitive, noise-critical portable systems where both power gating and analog integrity are required.

Availability

LD2982BM40R is available at Aetrix Electronics and suitable for mobile baseband power, wearable sensor hubs, industrial HMI displays, and medical point-of-care monitors requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LD2982BM40R 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 microcontrollers, power management ICs, analog chips, and MEMS sensors for industrial, automotive, and consumer markets.

The LD2982 series belongs to ST's precision low-dropout regulator product line, engineered specifically for ultra-low-noise, ultra-low-quiescent-current applications in portable and battery-operated equipment.

FAQ

What is the minimum output capacitor value required for stability with LD2982BM40R?

Per STMicroelectronics' application note, a 2.2 µF low-ESR ceramic capacitor is required on the output for the 1.8 V version to ensure stability across temperature and load. Using less than this value risks oscillation unless a series resistor is added to emulate higher ESR - but that degrades transient response and noise performance.

How does the BYPASS pin reduce output noise?

The BYPASS pin connects directly to the internal voltage reference node. Adding a 10 nF capacitor from BYPASS to GND filters high-frequency reference noise before it modulates the error amplifier, lowering integrated output noise from ~70 µV_RMS to 30 µV_RMS over 300 Hz–50 kHz - a verified 57 % reduction per datasheet testing.

Can LD2982BM40R be used without connecting the INHIBIT pin?

No - the INHIBIT pin must never be left floating. If shutdown control is unused, ST specifies tying INHIBIT directly to the input voltage (IN) to maintain permanent ON operation. Leaving it unconnected risks erratic enable/disable behavior due to noise coupling or internal leakage paths.

Does LD2982BM40R support reverse current protection?

Yes - the internal PNP pass transistor lacks an inherent body diode, preventing reverse current flow from OUT to IN when output voltage exceeds input. However, a small reverse current (~160 µA) flows through internal feedback resistors to GND if V_OUT > V_IN; this is non-destructive and specified in the datasheet under "Reverse current" test conditions.

LD2982BM40R 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):: 4V

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

LD2982BM40R FAQ

1.How can I place an order for LD2982BM40R through Aetrix?

Please submit a Request for Quotation (RFQ) for LD2982BM40R 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 LD2982BM40R reliable?

The price and inventory of LD2982BM40R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LD2982BM40R is usually 5 days.

3.What payment methods are accepted for LD2982BM40R?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LD2982BM40R transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LD2982BM40R?

LD2982BM40R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LD2982BM40R 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 LD2982BM40R?

For technical support, including LD2982BM40R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LD2982BM40R requirements.

6.How does Aetrix verify that LD2982BM40R is sourced from the original manufacturer or authorized distributors?

All LD2982BM40R 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 LD2982BM40R meets industry standards.

7.What is the process for return or replacement of LD2982BM40R?

All LD2982BM40R units undergo pre-shipment inspection (PSI). If there is an issue with LD2982BM40R, 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 LD2982BM40R part is unused and in its original packaging.

Return procedure for LD2982BM40R:

1.Submit a request within 90 days.

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

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