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

STMicroelectronics E-L4971D013TR

Name: E-L4971D013TR
Brand: STMicroelectronics
SKU: E-L4971D013TR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: E-L4971D013TR

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

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

Datasheet:: E-L4971D013TR.pdf

Description:: IC REG BUCK ADJ 1.5A 16SO W

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Product details

Overview

E-L4971D013TR from STMicroelectronics is a monolithic step-down switching regulator IC delivering up to 1.5A output current, operating from 8V to 55V input, with adjustable output voltage from 3.3V to 50V, internal 3.3V ±1% reference, and switchable frequency up to 300kHz. It integrates a power D-MOS transistor (R_DS(on) = 0.25Ω typ.), supports zero-load operation, and is used in industrial power supplies requiring wide-input, high-efficiency DC-DC conversion.

For engineers reviewing the E-L4971D013TR datasheet, E-L4971D013TR pinout, E-L4971D013TR application, or E-L4971D013TR equivalent, key selection criteria include input voltage range (8–55V), output adjustability (3.3–50V), thermal shutdown, hiccup-mode current limiting, and SO16W package compatibility with surface-mount assembly.

Technical Context

The L4971 employs voltage feedforward control to maintain stable regulation across wide input variations, eliminating need for complex compensation under line transients. Its error amplifier features 57dB open-loop gain and 2.5mS transconductance, enabling precise feedback loop stability with external RC networks on COMP and FB pins.

Internal architecture includes a PWM comparator with 95–97% max duty cycle, soft-start circuitry with 30–50µA charge current, and dual-stage overcurrent protection: pulse-by-pulse limiting (2–3A) followed by hiccup mode during sustained short-circuit conditions.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Current	1.5A continuous; supports full load without derating at T_j ≤ 100°C in SO16W package
Input Voltage Range	8V to 55V; enables direct use with 12V/24V/48V industrial bus rails and battery systems
Output Voltage Range	3.3V to 50V; set via external resistor divider on FB pin; 3.3V fixed when FB tied directly to output
Switching Frequency	Adjustable 90–300kHz via R_OSC/C_OSC; higher frequencies reduce inductor size but increase switching losses
R_DS(on)	0.25Ω typical; minimizes conduction loss and improves efficiency at 1.5A output
Reference Voltage	3.3V ±1% at 25°C; low tempco (0.4mV/°C) ensures stable output across -40°C to 125°C junction range
Quiescent Current	4–6mA operating; drops to 100–300µA in inhibit (standby) mode for low-power system states

Pinout & Package

Package: SO16W (wide-body SOIC-16), RoHS-compliant, surface-mount, thermal pad not electrically connected. Pin pitch: 1.27mm; body dimensions: 10.5 × 7.6mm (max).

Pin/Terminal	Circuit Role	Design Meaning
GND (Pin 2)	Power and signal ground reference	Common return path for internal bias, error amp, and PWM logic; must be low-impedance connection to PCB ground plane
SS_INH (Pin 3)	Soft-start timing / inhibit control	Capacitor to ground sets soft-start ramp time; logic-low disables IC and reduces I_Q to ≤300µA
OSC (Pin 4)	Oscillator timing node	External R+C network sets switching frequency; also enables automatic voltage feedforward compensation
OUT (Pins 5,6)	Power switch output	Drives external inductor; pins paralleled for lower resistance and thermal spreading
VCC (Pin 11)	Unregulated input supply	Accepts 8–55V; powers internal circuitry and bootstrap capacitor charging circuit
BOOT (Pin 12)	Bootstrap gate drive supply	Capacitor between BOOT and OUT provides gate drive voltage > V_OUT for internal N-channel DMOS
COMP (Pin 13)	Error amplifier output	Connects to external compensation network (RC) to stabilize feedback loop phase margin
FB (Pin 14)	Feedback input	Monitors output via resistive divider; 3.3V threshold triggers regulation; open-loop protection disables PWM if disconnected

Key Features

Feature	Design Value
Voltage feedforward regulation	Compensates for input ripple without additional sensing; maintains ±3mV line regulation over 8–55V input range
Pulse-by-pulse + hiccup overcurrent protection	2.5A typical current limit per cycle; transitions to low-duty-cycle hiccup mode after 3 consecutive faults to prevent thermal runaway
Zero-load operation capability	Stable regulation down to 0A output; no minimum load requirement simplifies design for variable-load systems
Integrated 0.25Ω DMOS power switch	Eliminates need for external MOSFET and driver; reduces BOM count and layout complexity while maintaining >85% efficiency at 1.5A
Thermal shutdown with hysteresis	Triggers at T_j ≥ 150°C; resumes operation only after cooldown to ~135°C to prevent cycling during overload

Applications

Industrial PLC Power Supply

Telecom Line Card Bias

Use Scenario: Provides isolated 5.1V/1.5A bias rail for FPGA, microcontroller, and interface ICs on modular PLC backplanes with 24V or 48V input.

IC Role / Device Role / Timing Role: Primary step-down regulator; handles wide input variation due to field wiring drop and battery backup transitions.

Use Value: Maintains <6mV load regulation and 86% efficiency at 1.5A, enabling compact heatsink-free design in confined DIN-rail enclosures.

Use Scenario: Generates stable 3.3V/1.5A supply for Ethernet PHYs and SerDes on telecom line cards powered from -48V DC distribution.

IC Role / Device Role / Timing Role: Input-stage buck converter; accepts boosted 8–55V intermediate rail derived from -48V via flyback or SEPIC.

Use Value: Delivers 10mV output ripple and 84% efficiency at 3.3V/1.5A, meeting stringent noise requirements for high-speed serial links.

Automotive Body Control Module

Test Equipment Auxiliary Rail

Use Scenario: Supplies 12V/1.5A for solenoid drivers and CAN transceivers in BCMs exposed to 12V battery with load-dump spikes up to 55V.

IC Role / Device Role / Timing Role: Main DC-DC regulator; withstands automotive transients via 58V absolute max input rating and hiccup-mode fault recovery.

Use Value: Survives ISO 7637-2 Pulse 5a (120V/50ms) when combined with external TVS; eliminates need for secondary clamping stage.

Use Scenario: Powers analog front-end circuits in portable test instruments requiring clean, adjustable 15V/1.5A rail from USB-C PD or Li-ion battery input.

IC Role / Device Role / Timing Role: Programmable output regulator; configured via R1/R2 divider to deliver exact voltage needed per instrument variant.

Use Value: Enables single-hardware platform supporting 3.3V, 5.1V, 12V, 15V, 18V, and 24V outputs - reducing SKU count and calibration effort.

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	Fixed 150kHz freq, 3A rating, no voltage feedforward, requires external MOSFET driver	Lacks hiccup mode and zero-load operation; less stable under wide-line variations	Preferred for cost-sensitive, fixed-frequency designs where input range ≤40V
MP2451DT-LF-Z	2A rating, 300kHz sync capability, integrated boot diode, no internal DMOS (external FET required)	Higher peak efficiency (>93%) but needs external high-side switch and gate driver	Chosen when board space allows discrete FET and higher current headroom is needed

Compared with LM2596S-ADJ and MP2451DT-LF-Z, E-L4971D013TR uniquely integrates feedforward control, hiccup-mode protection, and zero-load operation in a single SO16W package - making it optimal for ruggedized, wide-input industrial and automotive DC-DC stages where reliability trumps marginal efficiency gains.

Availability

E-L4971D013TR is available at Aetrix Electronics and suitable for industrial PLC power supplies, telecom line card biasing, automotive body control modules, and test equipment auxiliary rails requiring stable component supply with long lifecycle assurance.

Supply support for E-L4971D013TR 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 analog, power, MCU, and sensor solutions for industrial, automotive, and consumer markets.

The L4971 belongs to ST's legacy monolithic DC-DC regulator product line, engineered specifically for high-reliability, wide-input industrial power conversion where integration, fault resilience, and thermal robustness outweigh ultra-high-frequency operation.

FAQ

What is the maximum recommended output voltage for E-L4971D013TR?

The device supports output voltages up to 50V, set by an external resistive divider on the FB pin. At 50V output, ensure V_CC remains within 8–55V and that external components (inductor, diode, capacitors) are rated for ≥63V to maintain safety margin and reliability.

Does E-L4971D013TR require an external bootstrap diode?

No. The L4971 uses an internal charge pump to drive the BOOT pin, eliminating the need for an external bootstrap diode. A ceramic capacitor (typically 100nF) between BOOT and OUT is sufficient for proper high-side gate drive of the integrated DMOS transistor.

How does the hiccup-mode protection behave during sustained short-circuit?

After three consecutive pulse-by-pulse current limit events, the IC enters hiccup mode: it shuts down for ~30ms, then attempts restart. This cycle repeats until fault clears, limiting average power dissipation to <100mW and preventing thermal damage without requiring manual reset.

Can E-L4971D013TR operate with no output load?

Yes. The regulator maintains stable 3.3V–50V output regulation with zero load current, verified across -40°C to 125°C junction temperature. Quiescent current remains at 4–6mA in active mode and drops to ≤300µA when SS_INH is pulled low.

E-L4971D013TR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

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):: 3.3V

Voltage - Output (Max):: 50V

Current - Output:: 1.5A

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

E-L4971D013TR FAQ

1.How can I place an order for E-L4971D013TR through Aetrix?

Please submit a Request for Quotation (RFQ) for E-L4971D013TR 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 E-L4971D013TR reliable?

The price and inventory of E-L4971D013TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for E-L4971D013TR is usually 5 days.

3.What payment methods are accepted for E-L4971D013TR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for E-L4971D013TR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for E-L4971D013TR?

E-L4971D013TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your E-L4971D013TR 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 E-L4971D013TR?

For technical support, including E-L4971D013TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your E-L4971D013TR requirements.

6.How does Aetrix verify that E-L4971D013TR is sourced from the original manufacturer or authorized distributors?

All E-L4971D013TR 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 E-L4971D013TR meets industry standards.

7.What is the process for return or replacement of E-L4971D013TR?

All E-L4971D013TR units undergo pre-shipment inspection (PSI). If there is an issue with E-L4971D013TR, 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 E-L4971D013TR part is unused and in its original packaging.

Return procedure for E-L4971D013TR:

1.Submit a request within 90 days.

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

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