L5970D013TR

STMicroelectronics L5970D013TR — 1 A Step-Down (Buck) Regulator, 4.4–36 V Input, SO-8

The STMicroelectronics L5970D013TR is a compact, monolithic step-down (buck) switching regulator that delivers up to 1 A of output current from a broad 4.4 V to 36 V input range. Part of the L5970 series, this regulator integrates the power switch, control logic, and protection functions into a single SO‑8 (narrow) package, making it an efficient, space-saving choice for point‑of‑load regulation in industrial and general embedded power designs. The “TR” suffix denotes tape‑and‑reel packaging for automated assembly.

Engineers and sourcing teams value the L5970D013TR for its balance of wide input voltage capability, adjustable output from approximately 1.2 V to 35 V, and essential protections like enable control, soft‑start, current limit, and thermal shutdown. Whether you’re stepping down from a 24 V industrial bus or deriving clean rails for digital electronics, this STMicroelectronics regulator offers a dependable, well-documented solution.

At-a-Glance Specifications

• Brand/Manufacturer: STMicroelectronics
• Series: L5970
• MPN: L5970D013TR
• Category: PMIC – DC-DC Step-Down (Buck) Regulators
• Topology: Step-Down (Buck)
• Input Voltage Range: 4.4 V to 36 V
• Adjustable Output Voltage: Approximately 1.2 V to 35 V (via external resistors)
• Output Current: 1 A (max)
• Switching Frequency (typ): 250 kHz
• Number of Outputs: 1
• Control/Protection: Enable, Soft‑Start, Current Limit, Thermal Shutdown
• Package: SO‑8 (Narrow)
• Packaging: Tape & Reel (TR)
• Mounting Type: Surface Mount
• Pin Count: 8
• RoHS Status: RoHS Compliant
• Lifecycle Status: Not specified in datasheet (check STMicroelectronics product page)

Note: Only parameters provided in the product data or official documentation are listed. If a parameter is not shown, it is not specified in the datasheet provided here.

Why Choose the STMicroelectronics L5970D013TR?

Key Benefits for Designers

• Wide input range for industrial rails: The 4.4–36 V input makes the L5970D013TR suitable for 12 V and 24 V systems, battery-powered devices, and distributed power architectures.
• Flexible output rails: With an adjustable output from about 1.2 V up to 35 V, you can generate common logic voltages and analog rails with a single device.
• Integrated protections: Enable control, soft‑start, current limiting, and thermal shutdown simplify design and help protect the load and the converter under fault or startup conditions.
• Compact implementation: The SO‑8 package conserves PCB area while providing a straightforward, low‑component-count design path for 1 A loads.
• Production-ready format: Supplied in tape‑and‑reel (TR), the L5970D013TR fits high‑volume, automated pick-and-place assembly lines.

Typical Use Cases

• Point‑of‑load regulation from a 12 V or 24 V bus
• Industrial and distributed power systems where space and reliability matter
• General-purpose step‑down conversion in embedded applications

How the L5970D013TR Fits Into Your Power Architecture

The STMicroelectronics L5970D013TR operates as a non-isolated buck converter, using an integrated high-side switch and control circuitry to reduce a higher DC input voltage to a lower, regulated output. With a typical switching frequency of 250 kHz, the device strikes a practical balance between efficiency, component size, and EMI considerations. Its adjustable output allows you to standardize on a single regulator for multiple rails by simply choosing different feedback resistor values.

The built-in soft‑start function moderates inrush current during startup, which is helpful when powering sensitive loads or when multiple rails come up simultaneously. The enable pin supports power sequencing and low-power standby modes. Current limit and thermal shutdown help safeguard the regulator and downstream circuits during overloads, short circuits, or thermal stress.

Because the switch, control loop, and protection are monolithically integrated, design effort is focused on selecting the inductor, input/output capacitors, and the feedback network to achieve the target voltage and transient performance.

Design and Implementation Notes

While detailed design equations and absolute limits are found in the official datasheet, the following practical guidance can help you get to a robust first-pass design more quickly. Always validate with bench measurements and the latest STMicroelectronics documentation.

Inductor Selection

• Target ripple current: Many designs choose an inductor ripple in the range of roughly 20–40% of the output current to balance transient response and efficiency. The typical 250 kHz switching frequency influences the inductance value needed for your chosen ripple.
• Saturation rating: Ensure the inductor’s saturation current comfortably exceeds the peak inductor current under worst-case conditions (including transient overshoot) to avoid saturation.
• DCR and core losses: Lower DC resistance improves efficiency, but check thermal rise and physical size trade-offs.

Input and Output Capacitors

• Input capacitor: Place a low-ESR ceramic capacitor close to the VIN and ground pins to mitigate ripple and switching spikes. Bulk capacitance may be added for long leads or noisy sources.
• Output capacitor: The output capacitor’s capacitance and ESR shape transient response and output ripple. Choose values suitable for your load dynamics and stability requirements.
• Voltage rating and temperature: Use capacitors with adequate voltage derating and stable characteristics across the expected temperature range.

Feedback Network and Output Voltage Adjustment

• Output setpoint: The L5970D013TR’s output is adjustable using an external resistive divider. Follow the datasheet’s guidance for recommended feedback network values and layout placement to minimize noise pickup.
• Tolerance: Account for resistor tolerances and reference accuracy when budgeting overall output-voltage tolerance.

Enable, Soft-Start, and Protections

• Enable pin: Connect to a logic control signal for power sequencing or to the input supply through a divider if you want a programmable UVLO-like behavior. Ensure logic levels align with the datasheet’s thresholds.
• Soft-start: The integrated soft-start reduces stress on the input supply and downstream circuits during turn-on. Coordinate with system sequencing where multiple rails must track.
• Current limit and thermal shutdown: These features provide fault resilience. Nonetheless, design for adequate thermal headroom and ensure worst-case loads do not rely on protection mechanisms in normal operation.

Thermal and Layout Considerations

• Thermal path: Although SO‑8 is compact, power dissipation can be significant at higher load currents and large step-down ratios. Provide ample copper area on the PCB for heat spreading.
• High-current loops: Minimize loop area for the switch path (high di/dt) to reduce EMI and ringing. Keep the input decoupling capacitor close to the device.
• Ground strategy: Use a solid ground plane and separate power ground from signal ground where possible, tying them at a single point near the device.

Note: Specific electrical characteristics beyond those listed above are not provided here; consult the STMicroelectronics datasheet for exact limits and design curves.

Applications

• Point-of-load regulation in digital systems
• Industrial and distributed power systems
• General-purpose step-down conversion where up to 1 A is required

The L5970D013TR’s broad input range and 1 A capability make it a practical regulator for powering microcontrollers, sensors, communication modules, and analog front ends from 12 V/24 V rails, assuming system requirements match the device’s specifications.

Ordering, Packaging, and Handling

Ordering Information

• Part Number: L5970D013TR
• Series: L5970
• Brand: STMicroelectronics

Package and Format

• Package: SO‑8 (Narrow), 8 pins
• Mounting Type: Surface Mount
• Packaging: Tape & Reel (TR) for automated assembly

This tape‑and‑reel variant is ideal for high‑volume production and helps streamline SMT assembly lines.

Lifecycle, Availability, and Sourcing

• Lifecycle Status: Not specified in the datasheet. Check the STMicroelectronics product page for the latest status and notifications.
• Inventory Quantity: 0 (at time of listing). For procurement planning, submit an RFQ for current lead time and pricing.
• Pricing and Terms: RFQ-based. Pricing depends on volume, delivery schedule, and market conditions.

Tip for buyers: When availability is tight, consider placing a forecast with flexible delivery windows. Include acceptable date-code ranges and packaging preferences (e.g., full reels) to reduce sourcing friction.

Compliance and Environmental Information

• RoHS: RoHS Compliant
• Additional Environmental or Safety Certifications: Not specified in the datasheet

If your project requires documentation beyond RoHS (e.g., REACH, material declarations), consult the STMicroelectronics product page or request compliance documentation directly.

Frequently Asked Questions (FAQs)

What is the input voltage range of the STMicroelectronics L5970D013TR?

The device operates from 4.4 V to 36 V.

What is the maximum output current?

Up to 1 A continuous output current.

Is the output voltage adjustable?

Yes. Using an external resistor divider, you can set the output from approximately 1.2 V to 35 V.

What package is used for the L5970D013TR?

An SO‑8 (narrow) surface-mount package, supplied here as tape‑and‑reel (TR).

What is the typical switching frequency?

Typical switching frequency is 250 kHz.

Does the L5970D013TR include protection features?

Yes. It includes enable control, soft‑start, current limit, and thermal shutdown.

Are there official drop-in replacements?

Not specified in the datasheet. If you require second-source options, consult STMicroelectronics for guidance or evaluate alternatives with matching electrical and pinout characteristics.

What about efficiency and thermal performance?

Not specified in the datasheet excerpt provided here. Efficiency depends on operating conditions, external components, and layout. Refer to the official datasheet for efficiency curves and thermal information.

Is synchronization, spread-spectrum, or frequency adjustability supported?

Not specified in the provided data. Review the datasheet for any optional timing or frequency control features.

Is the device suitable for 24 V industrial systems?

Yes, provided your input remains within 4.4–36 V and the design respects the device’s operating limits, the L5970D013TR is suitable for common 24 V rails.

Practical Selection Checklist

• Input source between 4.4 V and 36 V
• Required output current ≤ 1 A
• Output rail between approximately 1.2 V and 35 V
• Typical switching frequency around 250 kHz is acceptable for your EMI and size constraints
• SO‑8 package and tape‑and‑reel format fit your assembly process
• Protections (enable, soft‑start, current limit, thermal shutdown) meet system safety and sequencing needs

If the above criteria describe your use case, the STMicroelectronics L5970D013TR is a strong candidate for evaluation.

Resources

• Product Page: https://www.st.com/en/power-management/l5970d.html
• Datasheet: https://www.st.com/resource/en/datasheet/l5970d.pdf

Always validate your design against the latest STMicroelectronics datasheet and application guidance for the L5970 series. If a needed parameter is not listed here, treat it as “Not specified in datasheet” and consult the official documentation or your ST support channel.

Summary

The STMicroelectronics L5970D013TR is a versatile, monolithic 1 A buck regulator that accepts 4.4–36 V inputs and provides an adjustable 1.2–35 V output in a compact SO‑8 package. With a typical 250 kHz switching frequency and integrated enable, soft‑start, current limit, and thermal shutdown, it offers a streamlined path to reliable point‑of‑load power for industrial and embedded applications. Its tape‑and‑reel packaging and RoHS compliance further support production readiness. For lifecycle details, additional compliance data, and real-time availability, consult STMicroelectronics and request a quote to align pricing and lead times with your build schedule.