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

STMicroelectronics L4970A

Name: L4970A
Brand: STMicroelectronics
SKU: L4970A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L4970A

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: Multiwatt-15 (Vertical, Bent and Staggered Leads)

Datasheet:: L4970A.pdf

Description:: IC REG BUCK ADJ 10A 15MULTIWATT

Quantity:: RFQ Add To RFQ list

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Inventory:1,334

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Product details

Overview

L4970A from STMicroelectronics is a monolithic 10A step-down switching regulator IC with adjustable output voltage (5.1V–40V), internal 5.1V ±2% reference, feed-forward line regulation, and integrated thermal shutdown, current limiting, soft start, reset/power fail, and UVLO with 1V hysteresis. It operates in continuous mode up to 500kHz and delivers high efficiency (up to 92%) in microprocessor power supply applications.

For engineers reviewing the L4970A datasheet, L4970A pinout, L4970A application, or L4970A equivalent, this device is selected for high-current DC-DC conversion where precise output regulation, system-level fault signaling (reset/power fail), fast transient response, and compact external component count are required.

Technical Context

The L4970A integrates a vertical DMOS power transistor using BCD mixed technology, enabling 10A continuous output with sub-50ns switching times and up to 500kHz operation. Its PWM control loop includes a sawtooth oscillator with voltage feed-forward, error amplifier with external RC compensation, latch-based single-pulse-per-cycle modulation, and internal current-sense resistor for cycle-by-cycle limiting.

Diagnostic functions include open-collector reset/power fail output triggered by input voltage threshold (5.1V on Pin 3) and output undervoltage detection (<5V), with programmable delay via external capacitor on Pin 5. Startup is managed by internal V_START (12V ±0.6V) and bootstrap gate drive (Pin 6) requiring external C_BOOT for high-side DMOS conduction.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Current	10A continuous - supports high-power embedded systems without external pass devices
Output Voltage Range	5.1V to 40V adjustable - enables single-regulator solutions for diverse rail requirements
Switching Frequency	Up to 500kHz - reduces size/cost of external inductors and capacitors
Reference Voltage	5.1V ±2% - provides stable feedback baseline for accurate output regulation
Efficiency	Up to 92% at 5A/5.1V - minimizes thermal load and improves power density
Duty Cycle Range	0–90% - supports wide input-output differentials including high-V_IN step-down
UVLO Threshold	11V turn-on with 1V hysteresis - ensures reliable startup while preventing oscillation near brownout

Pinout & Package

Package: Multiwatt15V - 15-lead plastic power package with integral heatsink tab (R_{th j-case} = 1°C/W), designed for high-power dissipation in industrial and computing environments.

Pin/Terminal	Circuit Role	Design Meaning
1 (OSC)	Oscillator Timing Input	Connects external R_OSC to ground to set constant charging current for frequency control
2 (COSC)	Oscillator Timing Capacitor	External C_OSC sets switching frequency together with R_OSC; supports up to 500kHz
3 (RESET IN)	Power Fail Input	5.1V threshold input for monitoring unregulated supply; enables system-level brownout detection
4 (RESET OUT)	Open-Collector Reset Output	Signals safe supply/output status to microprocessor; sinks up to 50mA
5 (RESET DELAY)	Reset Delay Timing	External C_DEL sets delay time before reset assertion during power-up or failure
6 (BOOTSTRAP)	Bootstrap Gate Drive	Drives internal DMOS gate via external C_BOOT; enables high-side switching with 0.5A peak drive
7 (OUTPUT)	Regulated Output	Main power output node; connects to LC filter and load; rated for 10A continuous
8 (GROUND)	Common Reference	System ground return for control circuitry, error amplifier, and protection logic
9 (SUPPLY)	Unregulated Input	Accepts 5.1–50V input; includes UVLO and internal current limiting for robustness
10 (COMP)	Error Amplifier Compensation	External RC network sets loop gain and phase margin for stable regulation
11 (FEEDBACK)	Voltage Feedback Input	Direct connection for 5.1V output; voltage divider for higher outputs
12 (SOFT START)	Soft Start Timing	External C_SS controls linear ramp of error amplifier to prevent inrush current
13 (SYNC)	External Synchronization	Allows multiple L4970A units to operate at same frequency and phase to reduce EMI
14 (VREF)	Internal Reference Output	Stable 5.1V ±2% source for feedback and external circuit biasing
15 (VSTART)	Internal Start-up Voltage	12V ±0.6V supply for initial gate drive and bootstrap charging during startup

Key Features

Feature	Design Value
Integrated DMOS Power Transistor	Enables 10A continuous output without external MOSFETs or drivers
Feed-Forward Line Regulation	Maintains <30mV line regulation over 15–50V input range, improving dynamic response
PWM Latch with Single-Pulse Control	Prevents multiple switching pulses per cycle, ensuring clean operation in noisy environments
Reset & Power Fail Circuitry	Provides microprocessor-compatible open-drain signal with programmable delay and dual-threshold detection
Thermal Shutdown with Hysteresis	Disables operation at ~150°C junction temperature and re-enables only after cooling by ~10°C

Applications

Industrial PLC Power Supply

Embedded Microprocessor Core Rail

Use Scenario: Centralized 12V/24V DC bus powering multiple I/O modules and communication interfaces in factory automation controllers.

IC Role / Device Role / Timing Role: Primary step-down regulator delivering stable 5.1V/10A to FPGA, MCU, and peripheral logic.

Use Value: Integrated current limiting and thermal shutdown eliminate need for external protection circuitry, reducing BOM count and board space.

Use Scenario: High-current core voltage supply for ARM Cortex-A series processors in edge computing gateways.

IC Role / Device Role / Timing Role: Main DC-DC converter with soft start and reset signaling to coordinate processor boot sequence.

Use Value: Programmable reset delay ensures memory initialization completes before CPU release, preventing boot failures.

Telecom Base Station Backplane

Test & Measurement Equipment

Use Scenario: Distributed power architecture supplying 12V/10A to RF front-end modules and digital signal processors.

IC Role / Device Role / Timing Role: High-efficiency buck regulator synchronized across multiple rails using Pin 13.

Use Value: 500kHz sync capability reduces conducted EMI and simplifies filter design in dense PCB layouts.

Use Scenario: Bench-top power supply module providing adjustable 5.1–24V output with precise load regulation.

IC Role / Device Role / Timing Role: Adjustable regulator with feed-forward compensation for low-noise, high-stability output.

Use Value: <15mV load regulation (2–10A) and <5mV line regulation ensure measurement accuracy under varying loads.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM2678-ADJ	5A max output, no integrated reset/power fail, no sync pin, lower max frequency (260kHz)	Suitable for cost-sensitive 5A designs without system-level fault signaling	Select when full 10A capability and diagnostic features are not required
TPS54620	6A output, 2.95–17V input, integrated FETs, no internal reference or reset output	Targeted for compact point-of-load applications with tight board area constraints	Choose for lower-input-voltage, space-constrained designs lacking microprocessor supervision needs

Compared with LM2678-ADJ and TPS54620, the L4970A uniquely combines 10A output, integrated 5.1V reference, reset/power fail signaling, and synchronization-making it optimal for industrial and embedded systems requiring robust, self-monitoring power delivery.

Availability

L4970A is available at Aetrix Electronics and suitable for industrial PLC power supplies, embedded microprocessor core rails, telecom base station backplanes, and test & measurement equipment requiring stable component supply and long-term design continuity.

Supply support for L4970A 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, specializing in power management, microcontrollers, and analog ICs for industrial, automotive, and consumer markets.

The L4970A belongs to ST's MultiPower BCD technology family-designed specifically for high-current, high-efficiency monolithic switching regulators targeting industrial control, computing, and telecom infrastructure.

FAQ

What is the minimum input voltage required for L4970A to start regulating?

The L4970A incorporates an undervoltage lockout (UVLO) with a typical turn-on threshold of 11V and 1V hysteresis. Below 10V, the device remains disabled; regulation begins only after the input voltage exceeds 11V and stabilizes. This ensures sufficient headroom for internal gate drive and bootstrap capacitor charging before enabling the DMOS switch.

How does the L4970A implement current limiting during overload or short-circuit conditions?

The L4970A uses internal metal-resistor current sensing and a comparator-driven latch to disable the DMOS transistor when load current exceeds ~13A (typical). The latch resets every 25µs (40kHz) via an internal oscillator, resulting in constant-current foldback mode-limiting average output to ~11–15A while maintaining fixed-frequency operation and preventing thermal runaway.

Can the L4970A be used to generate an output voltage below 5.1V?

No-the internal 5.1V reference is the lowest stable regulation point. The feedback pin (Pin 11) is designed for direct connection to output for 5.1V operation or via resistive divider for higher voltages. Attempting sub-5.1V regulation violates the error amplifier's common-mode input range and disables proper regulation; external reference injection is not supported.

What is the role of the bootstrap capacitor (Pin 6), and how is its value selected?

The bootstrap capacitor (C_BOOT) provides gate drive voltage above the output rail to fully enhance the internal high-side DMOS transistor. Its value depends on switching frequency: ≥220nF at 200kHz, ≥100nF at 500kHz. Insufficient capacitance causes gate underdrive, increased conduction losses, and potential thermal failure under full load.

L4970A Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: Multiwatt-15 (Vertical, Bent and Staggered Leads)

Packaging:: Tube

Product Status:: Obsolete

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Adjustable

Number of Outputs:: 1

Voltage - Input (Min):: 15V

Voltage - Input (Max):: 50V

Voltage - Output (Min/Fixed):: 5.1V

Voltage - Output (Max):: 40V

Current - Output:: 10A

Frequency - Switching:: 200kHz

Synchronous Rectifier:: No

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 15-Multiwatt

L4970A FAQ

1.How can I place an order for L4970A through Aetrix?

Please submit a Request for Quotation (RFQ) for L4970A 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 L4970A reliable?

The price and inventory of L4970A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L4970A is usually 5 days.

3.What payment methods are accepted for L4970A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L4970A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L4970A?

L4970A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L4970A 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 L4970A?

For technical support, including L4970A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L4970A requirements.

6.How does Aetrix verify that L4970A is sourced from the original manufacturer or authorized distributors?

All L4970A 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 L4970A meets industry standards.

7.What is the process for return or replacement of L4970A?

All L4970A units undergo pre-shipment inspection (PSI). If there is an issue with L4970A, 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 L4970A part is unused and in its original packaging.

Return procedure for L4970A:

1.Submit a request within 90 days.

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

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