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

STMicroelectronics L5973D013TR

Name: L5973D013TR
Brand: STMicroelectronics
SKU: L5973D013TR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L5973D013TR

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

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

Datasheet:: L5973D013TR.pdf

Description:: IC REG BUCK ADJ 2.5A 8HSOP

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Product details

Overview

L5973D013TR from STMicroelectronics is a monolithic step-down switching regulator with an internal 2.5 A P-channel D-MOS switch, 4–36 V input range, adjustable 1.235–35 V output, and fixed 250 kHz switching frequency. It delivers >2 A DC load current in typical configurations and supports zero-load operation, thermal shutdown, and synchronization-used in LCD monitors, STB power supplies, and industrial DC-DC converters.

For engineers reviewing the L5973D013TR datasheet, L5973D013TR pinout, L5973D013TR application, or L5973D013TR equivalent, key selection criteria include its SO8 exposed-pad thermal performance (R_thJA = 40 °C/W), 1.235 V feedback reference tolerance (±1.2%), pulse-by-pulse current limiting, and INH-controlled zero-quiescent-current shutdown mode.

Technical Context

The L5973D013TR implements voltage-mode control with feedforward compensation, using an internal error amplifier (57 dB open-loop gain, 2.3 mS transconductance) and COMP pin for external frequency compensation. Its P-channel MOSFET switch (R_DS(on) = 250 mΩ typ.) enables low dropout operation up to 100% duty cycle.

It integrates synchronization capability via the SYNC pin (2.5 V high threshold, 0.74 V low), supports master/slave configuration, and includes protection against feedback disconnection, overtemperature, and short-circuit via internal current limiting (2.5–3.5 A trip range).

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	4 V to 36 V - supports 5 V bus systems and automotive battery inputs without pre-regulation.
Output Voltage Range	1.235 V to 35 V - set by external resistor divider on FB pin; 1.235 V nominal reference with ±1.2% tolerance at 25 °C.
Switch Current Limit	2.5 A min - ensures ≥2 A continuous DC output under thermal limits (T_J ≤ 125 °C) in HSOP8 exposed-pad package.
Switching Frequency	250 kHz fixed - enables compact magnetics (e.g., 15 µH inductor) and predictable EMI profile without external timing components.
Quiescent Current	3 mA typ. operating / 80–150 µA standby - enables low-power modes when INH is asserted high.
Thermal Resistance	R_thJA = 40 °C/W - achieved via HSOP8 exposed pad; allows >2 A output at T_A = 60 °C without forced air.
Reference Voltage	3.3 V ±2% on VREF pin - provides stable bias for external circuitry; no capacitor required for stability.

Pinout & Package

Package: HSOP8 with exposed thermal pad (JEDEC MO-220 variant), 5.0 mm × 6.2 mm footprint, 1.27 mm pitch, R_thJA = 40 °C/W when mounted per datasheet layout guidelines.

Pin/Terminal	Circuit Role	Design Meaning
OUT (Pin 1)	Power switch output node	Connects to inductor and output capacitor; carries pulsed high-current switching waveform.
SYNC (Pin 2)	Synchronization input/output	Accepts external clock (2.5 V logic high) or drives slave devices; enables multi-phase operation.
INH (Pin 3)	Enable/disable control	Active-high logic input; open-circuit defaults to disable via internal pull-up; grounds to enable.
COMP (Pin 4)	Error amplifier output	Drives external RC compensation network to stabilize loop response and prevent oscillation.
FB (Pin 5)	Feedback input	Monitors output via resistive divider; regulates output to 1.235 V at this pin; disconnect protection active.
VREF (Pin 6)	Internal 3.3 V reference	Stable, low-noise reference source for external circuitry; no bypass cap needed.
GND (Pin 7)	Power and signal ground	Common return for switch, control circuitry, and feedback; tied to exposed pad for thermal path.
VCC (Pin 8)	Unregulated input supply	Primary power input (4–36 V); powers internal circuitry and gate driver; decoupling required.

Key Features

Feature	Design Value
Zero-load operation	Maintains regulation with no output current draw, enabling always-on auxiliary rails in standby systems.
Voltage feedforward	Improves line transient response by scaling PWM duty cycle with input voltage, reducing output deviation during VIN steps.
Internal current limiting	Pulse-by-pulse peak detection prevents inductor saturation and MOSFET failure during overload or short-circuit events.
Thermal shutdown	Halts switching at T_J ≥ 150 °C and resumes automatically after cooldown, protecting silicon and PCB.
Inhibit function	Reduces total quiescent current to <150 µA when INH is high, supporting ultra-low-power system sleep states.

Applications

STB Power Supply

LCD Monitor DC-DC

Use Scenario: Provides regulated 3.3 V and 5 V rails from 12 V input in satellite set-top box mainboard.

IC Role / Device Role / Timing Role: Primary buck converter delivering >2 A at 3.3 V with tight line/load regulation and low EMI.

Use Value: Enables single-stage conversion from 12 V bus, eliminating linear post-regulators and reducing board area by 35% vs. discrete solutions.

Use Scenario: Generates 5 V and 12 V bias for TFT panel drivers and backlight ICs in 24-inch LCD monitor.

IC Role / Device Role / Timing Role: Adjustable-output buck regulator configured for 5 V/2 A output with SYNC pin daisy-chained to secondary converter.

Use Value: Fixed 250 kHz frequency simplifies EMI filter design; exposed pad maintains junction temperature <95 °C at full load.

Industrial DC-DC Converter

Car Radio Power Management

Use Scenario: Replaces aging linear regulators in programmable logic controller (PLC) I/O module power stage.

IC Role / Device Role / Timing Role: High-input-voltage buck regulator accepting 24 V nominal (up to 36 V transients) and delivering 3.3 V to microcontroller and sensors.

Use Value: 4 V minimum input supports brownout operation down to 4.4 V; thermal shutdown prevents field failures in enclosed enclosures.

Use Scenario: Supplies 3.3 V to infotainment SoC and 5 V to USB ports in automotive head unit powered from 9–16 V battery.

IC Role / Device Role / Timing Role: Automotive-grade buck controller with wide VIN range and INH-controlled sleep mode during ignition-off.

Use Value: 80–150 µA standby current meets OEM quiescent drain requirements; 100% duty cycle supports cold-crank down to 4.4 V.

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	3 A switch, 150 kHz fixed frequency, TO-263 package, no SYNC or INH pins	Lacks synchronization and ultra-low-I_Q inhibit; higher R_thJA (~65 °C/W) limits high-current density layouts	Choose for cost-sensitive, non-synchronized designs where thermal margin >25 °C is available.
MP1584EN-LF-Z	3 A switch, 1.5 MHz switching, SOIC-8, no VREF pin or feedforward	Higher frequency reduces inductor size but increases switching loss; no dedicated reference output for auxiliary circuits	Prefer for space-constrained designs needing smaller magnetics, accepting reduced efficiency at high I_OUT.

Compared with LM2596S-ADJ and MP1584EN-LF-Z, the L5973D013TR uniquely combines 250 kHz fixed frequency, integrated 3.3 V reference, voltage feedforward, and sub-150 µA inhibit current-making it optimal for thermally constrained, multi-rail, and automotive-bus-compatible systems requiring precise regulation and low standby drain.

Availability

L5973D013TR is available at Aetrix Electronics and suitable for STB power supplies, LCD monitor DC-DC stages, and industrial PLC I/O modules requiring stable component supply across extended temperature and long-lifecycle programs.

Supply support for L5973D013TR 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, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The L5973D belongs to ST's monolithic DC-DC converter product line, engineered for high-current, wide-input-voltage industrial and automotive power conversion where thermal efficiency, reliability, and integration of protection features are critical.

FAQ

What is the maximum continuous output current achievable with L5973D013TR?

The L5973D013TR guarantees a minimum switch current limit of 2.5 A and can deliver >2 A DC output continuously under standard conditions (T_A = 60 °C, HSOP8 mounted per datasheet layout, 12 V input, 3.3 V output). Actual current depends on thermal design, input/output voltage differential, and PCB copper area-efficiency curves show 90% at 2 A/5 V output with 12 V input.

Can L5973D013TR operate with input voltage below 5 V?

Yes-the device operates from 4 V to 36 V input, making it compatible with 5 V bus systems and capable of sustaining regulation during automotive cold-crank events down to 4.4 V. The 100% duty-cycle capability ensures no dropout at low VIN, provided external components (e.g., inductor DCR, diode VF) support the required conduction time.

How does the INH pin affect quiescent current and startup behavior?

When INH is driven high (>2.2 V), the device enters zero-current-consumption inhibit mode, drawing only 80–150 µA from VCC. If left unconnected, the internal pull-up disables the IC; grounding INH enables normal operation. Startup delay is negligible (<10 µs), and no external soft-start circuit is required due to internal ramp control.

Is external compensation mandatory for stable operation?

Yes-COMP pin requires an external RC network (e.g., 22 nF + 4.7 kΩ) to set dominant pole and phase margin. The datasheet provides design equations and stability criteria; omitting compensation causes oscillation or poor transient response. Compensation values depend on output voltage, inductor value, and output capacitance ESR.

L5973D013TR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Active

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Output Type:: Adjustable

Number of Outputs:: 1

Voltage - Input (Min):: 4V

Voltage - Input (Max):: 36V

Voltage - Output (Min/Fixed):: 1.235V

Voltage - Output (Max):: 35V

Current - Output:: 2.5A

Frequency - Switching:: 250kHz

Synchronous Rectifier:: No

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-HSOP

L5973D013TR FAQ

1.How can I place an order for L5973D013TR through Aetrix?

Please submit a Request for Quotation (RFQ) for L5973D013TR 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 L5973D013TR reliable?

The price and inventory of L5973D013TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L5973D013TR is usually 5 days.

3.What payment methods are accepted for L5973D013TR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L5973D013TR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L5973D013TR?

L5973D013TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L5973D013TR 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 L5973D013TR?

For technical support, including L5973D013TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L5973D013TR requirements.

6.How does Aetrix verify that L5973D013TR is sourced from the original manufacturer or authorized distributors?

All L5973D013TR 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 L5973D013TR meets industry standards.

7.What is the process for return or replacement of L5973D013TR?

All L5973D013TR units undergo pre-shipment inspection (PSI). If there is an issue with L5973D013TR, 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 L5973D013TR part is unused and in its original packaging.

Return procedure for L5973D013TR:

1.Submit a request within 90 days.

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

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