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

STMicroelectronics E-L5970D

Name: E-L5970D
Brand: STMicroelectronics
SKU: E-L5970D
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: E-L5970D

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

Package:: 8-SOIC (0.154", 3.90mm Width)

Datasheet:: E-L5970D.pdf

Description:: IC REG BUCK ADJ 1A 8SOIC

Quantity:: RFQ Add To RFQ list

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Inventory:4,506

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Product details

Overview

L5970D from STMicroelectronics is a monolithic step-down switching regulator featuring an internal P-channel D-MOS switch (R_DS(on) = 250 mΩ), delivering up to 1 A at adjustable output voltages from 1.2 V to 35 V, with 4.4 V to 36 V input range and fixed 250 kHz switching frequency-used in DC-DC conversion for LCD monitors, car radios, and industrial DC-DC modules.

For engineers reviewing the L5970D datasheet, L5970D pinout, L5970D application, or L5970D equivalent, key selection considerations include its 3.3 V reference accuracy (±2%), zero-load operation capability, internal current limiting (1.87 A typ), thermal shutdown, and synchronization support for multi-regulator systems.

Technical Context

The L5970D implements voltage-mode control with feedforward compensation, enabling stable regulation across wide input ranges without external loop compensation complexity. Its error amplifier features 65 dB open-loop gain and 2.3 mS transconductance, driving the COMP pin for external RC network tuning.

It integrates pulse-by-pulse current limiting with frequency modulation for short-circuit protection, supports 100% duty cycle for low-dropout operation, and includes dedicated INH logic (active-high enable) and SYNC interface for master-slave timing coordination-enabling precise interleaving in multi-phase designs.

Key Specifications

Parameter	Value and Actual Design Meaning
Output current	Up to 1 A continuous; supports peak load transients without foldback due to internal current limit (1.87 A typ).
Input voltage range	4.4 V to 36 V; compatible with 5 V bus rails and automotive battery inputs (up to 35 V nominal).
Switching frequency	250 kHz fixed (212–280 kHz over temp); enables compact magnetics and predictable EMI filtering.
Reference voltage	3.3 V ±2% (3.234–3.366 V); used for feedback divider setting and stable output regulation.
R_DS(on)	250 mΩ typical; reduces conduction loss and thermal stress at full load in SO8 package.
Quiescent current	5 mA operating; drops to 100 µA in inhibit mode-critical for always-on subsystems.
Thermal shutdown	Activates at T_J = 150 °C; protects device during overload or poor heatsinking conditions.

Pinout & Package

Supplied in SO8 (Small Outline 8-pin) package per JEDEC MS-012, with ECOPACK® lead-free finish and 120 °C/W junction-to-ambient thermal resistance on standard PCB layout.

Pin/Terminal	Circuit Role	Design Meaning
OUT (Pin 1)	Power switch output	Drives external inductor; connects directly to L1 node in buck topology.
SYNC (Pin 2)	Timing synchronization input/output	Accepts external clock (2.5 V high threshold) or outputs synchronized pulse for multi-regulator phase alignment.
INH (Pin 3)	Enable/disable control	Active-high logic; open-circuit disables device via internal pull-up; grounding enables operation.
COMP (Pin 4)	Error amplifier output	Provides compensation node for external RC network to stabilize feedback loop dynamics.
FB (Pin 5)	Feedback input	Senses output voltage via resistive divider; 1.235 V threshold sets regulated output (V_OUT = 1.235 × (1 + R1/R2)).
VREF (Pin 6)	Internal reference output	3.3 V precision reference; no bypass capacitor required for stability.
GND (Pin 7)	Power and signal ground	Common return for internal circuitry, feedback, and power stage; requires low-impedance PCB connection.
VCC (Pin 8)	Unregulated input supply	Connects to raw input rail (4.4–36 V); powers internal logic and gate driver.

Key Features

Feature	Design Value
Voltage feedforward	Compensates for input ripple without additional sensing components-improves transient response under line variation.
Zero-load operation	Maintains regulation down to 0 A output current-enables standby modes in consumer electronics without dropout.
Internal current limiting	Pulse-by-pulse protection with frequency modulation prevents thermal runaway during short circuits.
100% duty cycle capability	Enables operation with V_IN − V_OUT < 1 V-ideal for low-dropout applications like 5 V-to-3.3 V conversion.
Feedback disconnection protection	Shuts down regulator if FB pin is open or disconnected-prevents uncontrolled overvoltage failure.

Applications

Car Radio Power Supply

LCD Monitor DC-DC Module

Use Scenario: Regulating 12 V automotive battery to stable 3.3 V/5 V for digital audio processors and display controllers.

IC Role / Device Role / Timing Role: Primary buck controller managing input transients, load steps, and thermal constraints in harsh automotive environments.

Use Value: 4.4 V minimum input enables reliable startup even during cold-crank events; thermal shutdown ensures safety during prolonged high-temp operation.

Use Scenario: Generating 5 V and 12 V rails from 24 V input in desktop LCD monitor power boards.

IC Role / Device Role / Timing Role: Adjustable-output buck regulator configured for multiple fixed outputs via resistor networks and auxiliary windings.

Use Value: 250 kHz fixed frequency simplifies EMI filter design; 1 A output supports backlight drivers and logic supplies simultaneously.

Industrial DC-DC Converter

XDSL Line Card Power

Use Scenario: Providing isolated 12 V/1 A output in DIN-rail mounted programmable logic controller (PLC) power stages.

IC Role / Device Role / Timing Role: Core switching regulator in non-isolated front-end stage, interfacing with upstream AC-DC or 48 V telecom input.

Use Value: Wide 4.4–36 V input accommodates 24 V nominal industrial buses with ±20% tolerance; SO8 package allows dense board layout.

Use Scenario: Generating 3.3 V for DSL PHY and microcontroller in broadband access equipment with strict efficiency targets.

IC Role / Device Role / Timing Role: High-efficiency point-of-load regulator operating from 5 V or 12 V intermediate bus.

Use Value: 90% peak efficiency at 5 V output reduces heat dissipation in fanless enclosures; synchronization avoids beat frequencies with other system clocks.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM2576-ADJ	Fixed 52 kHz frequency; higher R_DS(on) (~300 mΩ); no SYNC or INH pins.	Lacks synchronization and enable control-unsuitable for multi-rail coordinated sequencing.	Choose when cost sensitivity outweighs feature requirements and lower-frequency EMI is acceptable.
TPS5430DDAR	3.5 A output; 500 kHz switching; integrated high-side FET; requires external compensation.	Higher current and frequency enable smaller passives but increase layout complexity and noise sensitivity.	Prefer for space-constrained designs needing >1 A or tighter output regulation with external compensation flexibility.

Compared with LM2576-ADJ and TPS5430DDAR, the L5970D offers balanced performance: moderate current (1 A), fixed 250 kHz frequency for predictable filtering, built-in protection features (INH, SYNC, feedback disconnect), and SO8 simplicity-making it optimal for mid-power industrial and consumer DC-DC modules where reliability and ease of use are prioritized over extreme density or current headroom.

Availability

L5970D is available at Aetrix Electronics and suitable for car radio power supplies, LCD monitor DC-DC modules, and industrial DC-DC converters requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for L5970D 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 L5970D belongs to ST's monolithic DC-DC converter product line, engineered for robust, low-component-count buck regulation in cost-sensitive and thermally constrained applications-from automotive infotainment to networking infrastructure.

FAQ

What is the minimum input voltage required for L5970D to regulate a 3.3 V output?

The L5970D requires a minimum input voltage of 4.4 V to maintain regulation at any output voltage-including 3.3 V-due to internal headroom needs of the P-channel MOSFET and control circuitry. Below 4.4 V, the device enters dropout or shuts down depending on load and temperature.

Can the L5970D be synchronized to an external clock source?

Yes-the SYNC pin accepts an external TTL/CMOS-compatible clock signal (2.5 V high threshold, 0.74 V low threshold) and can also output a synchronized pulse for coordinating multiple regulators. This enables phase interleaving to reduce input/output ripple in multi-rail systems.

How does the L5970D handle open-feedback (FB pin disconnected) faults?

The L5970D detects open-feedback conditions via internal monitoring of the FB pin voltage and triggers automatic shutdown to prevent uncontrolled output overvoltage. This protection activates regardless of INH state and remains active until FB is reconnected within specification.

Is an external compensation network required for stable operation?

Yes-an external RC network must be connected between COMP and GND to set loop bandwidth and phase margin. The datasheet provides recommended values (e.g., 22 nF + 4.7 kΩ) based on typical 3.3 V output configurations; values scale with output voltage and inductor choice.

E-L5970D Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 8-SOIC (0.154", 3.90mm Width)

Packaging:: Tube

Product Status:: Obsolete

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Adjustable

Number of Outputs:: 1

Voltage - Input (Min):: 4.4V

Voltage - Input (Max):: 36V

Voltage - Output (Min/Fixed):: 1.2V

Voltage - Output (Max):: 35V

Current - Output:: 1A

Frequency - Switching:: 250kHz

Synchronous Rectifier:: No

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

E-L5970D FAQ

1.How can I place an order for E-L5970D through Aetrix?

Please submit a Request for Quotation (RFQ) for E-L5970D 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-L5970D reliable?

The price and inventory of E-L5970D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for E-L5970D is usually 5 days.

3.What payment methods are accepted for E-L5970D?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for E-L5970D transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for E-L5970D?

E-L5970D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your E-L5970D 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-L5970D?

For technical support, including E-L5970D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your E-L5970D requirements.

6.How does Aetrix verify that E-L5970D is sourced from the original manufacturer or authorized distributors?

All E-L5970D 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-L5970D meets industry standards.

7.What is the process for return or replacement of E-L5970D?

All E-L5970D units undergo pre-shipment inspection (PSI). If there is an issue with E-L5970D, 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-L5970D part is unused and in its original packaging.

Return procedure for E-L5970D:

1.Submit a request within 90 days.

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

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