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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - DC DC Switching Regulators

STMicroelectronics L4976D

Name: L4976D
Brand: STMicroelectronics
SKU: L4976D
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L4976D

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 16-SOIC (0.295", 7.50mm Width)

Datasheet:: L4976D.pdf

Description:: IC REG BUCK ADJ 1A 16SO W

Quantity:: RFQ Add To RFQ list

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Inventory:1,150

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Product details

Overview

L4976D from STMicroelectronics is a monolithic step-down switching regulator IC delivering 1 A continuous output current, operating from 8 V to 55 V input, with adjustable output voltage (0.5 V to 50 V) and internal 5.1 V reference. It integrates a power D-MOS transistor (R_DS(ON) = 0.25 Ω typ.), supports up to 300 kHz switching frequency, and features voltage feed-forward, zero-load operation, and hiccup-mode short-circuit protection - used in industrial DC-DC conversion stages requiring wide-input, high-efficiency regulation.

For engineers reviewing the L4976D datasheet, L4976D pinout, L4976D application, or L4976D equivalent, key selection considerations include its SO16W package thermal resistance (110 °C/W), internal current limiting (1.5–2.5 A typ.), feedback disconnection protection, and compatibility with external RC-based frequency tuning for noise-sensitive power supplies.

Technical Context

The L4976D implements a voltage-mode PWM controller with integrated power switch and error amplifier. Its oscillator uses an external resistor-capacitor network on the OSC pin to set switching frequency (90–300 kHz), while voltage feed-forward dynamically adjusts duty cycle in response to input ripple - improving transient rejection without increasing loop gain.

Internal protection includes pulse-by-pulse current limiting, thermal shutdown at 150 °C, and dedicated FB pin monitoring that disables switching if feedback is disconnected. The COMP pin provides direct access to the error amplifier output for custom compensation networks, enabling stable regulation across wide load and line variations.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	8 V to 55 V - supports unregulated industrial rails including 12 V, 24 V, and 48 V systems without pre-regulation.
Output Current	1 A continuous - sufficient for powering microcontrollers, sensors, and interface ICs in embedded power supplies.
Reference Voltage	5.1 V ±1% - enables precise feedback setting for fixed or adjustable outputs via external resistor divider.
Switching Frequency	Up to 300 kHz - balances EMI control and inductor size; adjustable via ROSC/COSC on OSC pin.
R_DS(ON)	0.25 Ω typical - reduces conduction loss and improves efficiency at full load (e.g., 85% at 3.3 V/1 A).
Thermal Resistance	110 °C/W (R_thJA) - requires minimal PCB copper area for SO16W package in ambient ≤60 °C environments.
Protection Features	Pulse-by-pulse current limit + hiccup mode + thermal shutdown + FB disconnection detection - ensures robust fault recovery without latch-up.

Pinout & Package

The L4976D is housed in a SO16W (Small Outline, 16-pin, Wide-body) surface-mount package with 1.27 mm pitch, 10.5 mm × 7.6 mm footprint, and 2.65 mm height - optimized for thermal dissipation and automated assembly.

Pin/Terminal	Circuit Role	Design Meaning
2 GND	Power Ground Reference	Primary return path for internal power stage and control circuitry; must connect to low-impedance ground plane.
3 VREF	5.1 V Precision Reference Output	Provides stable 20 mA sink/source reference for external feedback divider or auxiliary biasing.
4 OSC	Oscillator Timing Input	RC network here sets switching frequency and enables automatic line feed-forward compensation.
5, 6 OUT	Power Switch Output Node	Drives external inductor; connects to BOOT capacitor and output filter - shared high-current path.
11 VCC	Unregulated Input Supply	Accepts 8–55 V input; powers internal logic and gate driver - bypass capacitor required near pin.
12 BOOT	Bootstrap Gate Drive Supply	Capacitor between BOOT and OUT generates floating voltage to fully enhance internal N-channel MOSFET.
13 COMP	Error Amplifier Output	Connects to external RC compensation network to stabilize feedback loop across load/line conditions.
14 FB	Feedback Input	Voltage divider from output connects here; open-circuit detection disables switching to prevent overvoltage.

Key Features

Feature	Design Value
Integrated Power D-MOS Transistor	R_DS(ON) = 0.25 Ω typ. eliminates external high-side switch and reduces BOM count and layout complexity.
Voltage Feed-Forward Regulation	Dynamic duty-cycle adjustment based on input voltage ripple improves line transient response without added compensation.
Zero-Load Operation	Maintains regulation down to 0 A output current - suitable for standby or low-power sleep modes in battery-backed systems.
Hiccup-Mode Short-Circuit Protection	Auto-retry behavior limits average power during sustained overload - prevents thermal runaway and enables self-recovery.
Feedback Disconnection Detection	Disables switching if FB pin floats or opens - prevents uncontrolled output voltage rise and protects downstream loads.

Applications

Industrial PLC Power Supply

Automotive Body Control Module

Use Scenario: Regulating 24 V vehicle battery to 5 V or 3.3 V for microcontroller and CAN transceiver power in body control units.

IC Role / Device Role / Timing Role: Primary buck converter providing isolated, stabilized low-voltage rail with high input voltage tolerance.

Use Value: Withstands load dump transients up to 55 V input and maintains regulation during cold-crank (down to 6 V) via wide VIN range.

Use Scenario: Converting 48 V telecom or server rack supply to 12 V intermediate bus for downstream point-of-load converters.

IC Role / Device Role / Timing Role: High-efficiency front-end step-down regulator enabling compact, thermally efficient multi-rail power architecture.

Use Value: 85% efficiency at 1 A/3.3 V and SO16W thermal performance allow operation without heatsink in enclosed enclosures.

Programmable Logic Controller (PLC) I/O Module

Smart Sensor Signal Conditioning Unit

Use Scenario: Generating stable 5 V rail from variable 12–36 V field wiring in industrial I/O modules with isolation barriers.

IC Role / Device Role / Timing Role: Isolated secondary-side regulator ensuring clean, ripple-free supply for analog-to-digital conversion and digital logic.

Use Value: 60 dB supply ripple rejection and 0.4 mV/°C reference drift enable <1 LSB error in 12-bit ADC systems over temperature.

Use Scenario: Powering MEMS accelerometers, pressure sensors, and signal chain amplifiers in condition-monitoring edge devices.

IC Role / Device Role / Timing Role: Low-noise, adjustable-output regulator supporting multiple sensor bias voltages (e.g., 2.5 V, 3.3 V, 5 V) from single design.

Use Value: Adjustable output (0.5–50 V) and COMP pin accessibility allow fine-tuned loop stability for ultra-low-noise analog front-ends.

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down regulator applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM2596S-ADJ	Lower max input (40 V), no voltage feed-forward, external MOSFET required, lower efficiency (~75% at 1 A)	Suitable for cost-sensitive consumer-grade supplies where input <40 V and transient performance is secondary	Choose when BOM cost is prioritized over thermal performance and line regulation fidelity.
MP2451DT-LF-Z	Higher switching frequency (up to 2 MHz), smaller external components, but lower max input (36 V) and no hiccup-mode protection	Better for space-constrained designs needing fast transient response, but unsuitable for >36 V industrial inputs	Prefer when PCB area is critical and input voltage remains below 36 V with predictable fault profiles.

Compared with LM2596S-ADJ and MP2451DT-LF-Z, the L4976D uniquely combines 55 V input tolerance, integrated MOSFET, hiccup-mode safety, and voltage feed-forward - making it optimal for ruggedized industrial and automotive power stages where reliability under wide-line variation is mandatory.

Availability

L4976D is available at Aetrix Electronics and suitable for industrial PLC power supplies, automotive body control modules, programmable logic controller I/O modules, and smart sensor signal conditioning units requiring stable component supply and long-term manufacturability.

Supply support for L4976D 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 power management applications.

The L4976D belongs to ST's legacy high-voltage buck regulator product line, engineered specifically for industrial and automotive power conversion where wide input range, integrated protection, and thermal robustness are essential.

FAQ

What is the minimum output voltage achievable with the L4976D?

The L4976D supports output voltages as low as 0.5 V using an external resistive feedback divider. This is enabled by its 5.1 V internal reference and high-precision error amplifier - allowing accurate regulation even at sub-1 V levels when paired with appropriate compensation and low-ESR output capacitors.

Can the L4976D operate without a heatsink in a 50°C ambient environment?

Yes - with its SO16W package (R_thJA = 110 °C/W) and 0.25 Ω R_DS(ON), the L4976D dissipates ~250 mW at 1 A/5 V output. At 50°C ambient, junction temperature remains below 80°C (T_J = 50 + 0.25 × 110), well within the -40°C to 150°C rating, eliminating need for external heatsinking.

How does the voltage feed-forward function improve performance?

Voltage feed-forward in the L4976D senses input voltage changes directly at the oscillator stage, adjusting PWM duty cycle in real time. This reduces dependence on feedback loop bandwidth, cuts line-induced output ripple by up to 20 dB, and improves transient response to input surges or sags without compromising stability.

Is the L4976D RoHS-compliant and halogen-free?

Yes - the L4976D is manufactured in ST's ECOPACK2-compliant SO16W package, meeting RoHS Directive 2011/65/EU and halogen-free requirements per IEC 61249-2-21. Full compliance documentation is available in ST's official product change notices and material declarations.

L4976D Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 16-SOIC (0.295", 7.50mm Width)

Packaging:: Tube

Product Status:: Active

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Adjustable

Number of Outputs:: 1

Voltage - Input (Min):: 8V

Voltage - Input (Max):: 55V

Voltage - Output (Min/Fixed):: 0.5V

Voltage - Output (Max):: 50V

Current - Output:: 1A

Frequency - Switching:: 100kHz ~ 300kHz

Synchronous Rectifier:: No

Operating Temperature:: -40°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-SO W

L4976D FAQ

1.How can I place an order for L4976D through Aetrix?

Please submit a Request for Quotation (RFQ) for L4976D 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 L4976D reliable?

The price and inventory of L4976D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L4976D is usually 5 days.

3.What payment methods are accepted for L4976D?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L4976D transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L4976D?

L4976D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L4976D 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 L4976D?

For technical support, including L4976D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L4976D requirements.

6.How does Aetrix verify that L4976D is sourced from the original manufacturer or authorized distributors?

All L4976D 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 L4976D meets industry standards.

7.What is the process for return or replacement of L4976D?

All L4976D units undergo pre-shipment inspection (PSI). If there is an issue with L4976D, 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 L4976D part is unused and in its original packaging.

Return procedure for L4976D:

1.Submit a request within 90 days.

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

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