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

STMicroelectronics L5972D

Name: L5972D
Brand: STMicroelectronics
SKU: L5972D
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L5972D

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

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

Datasheet:: L5972D.pdf

Description:: IC REG BUCK ADJ 2A 8SOIC

Quantity:: RFQ Add To RFQ list

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Inventory:688

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Product details

Overview

L5972D from STMicroelectronics is a monolithic step-down switching regulator with an integrated 2A P-channel D-MOS switch (R_DS(on) = 250 mΩ typ), operating from 4.4V to 36V input, delivering adjustable output from 1.235V to 35V at up to 1.5A DC load current, and featuring fixed 250kHz switching frequency and voltage feedforward for line regulation - used in 5V-bus-powered computer peripherals and industrial DC-DC converters.

For engineers reviewing the L5972D datasheet, L5972D pinout, L5972D application, or L5972D equivalent, key selection considerations include its 2A internal switch rating, 1.235V feedback reference, SO8 thermal resistance (65°C/W), pulse-by-pulse current limiting, and compatibility with low-ESR ceramic output capacitors in compact buck designs.

Technical Context

The L5972D implements a voltage-mode PWM controller with internal error amplifier, COMP pin for Type II/III compensation, and FB pin referenced to 1.235V ±1.2%. Its voltage feedforward architecture dynamically adjusts duty cycle based on input voltage to maintain stable loop gain across wide V_IN range.

It integrates thermal shutdown, feedback disconnection protection, and zero-load operation capability. The 250kHz fixed-frequency oscillator enables predictable EMI filtering and avoids subharmonic oscillation without external synchronization.

Key Specifications

Parameter	Value and Actual Design Meaning
Input voltage range	4.4V to 36V - supports 5V bus and automotive battery inputs without pre-regulation
Output voltage range	1.235V to 35V - set via external resistor divider; 1.235V reference enables precise low-voltage rails
Switch current limit	2A min., 2.5A typ. - enables ≥1.5A continuous DC output with proper thermal design
Switching frequency	250kHz fixed - simplifies filter design and EMI compliance vs. variable-frequency alternatives
R_DS(on)	250 mΩ typ. - reduces conduction loss and heat generation in high-current buck stages
Quiescent current	3 mA typ. - supports low-power standby modes without disabling regulator
Thermal resistance	65°C/W (J-A) - requires minimal copper area for 1.5A operation at ambient ≤70°C

Pinout & Package

Package: SO8 (ECOPACK®, lead-free, JEDEC-standard 5.0 × 4.0 mm body).

Pin/Terminal	Circuit Role	Design Meaning
1 OUT	Power switch output	Drives external inductor; connects directly to SW node of buck topology
2,3,6,7 GND	Power and signal ground	Four dedicated ground pins minimize ground bounce and improve thermal dissipation
4 COMP	Error amplifier output	Accepts Type II/III compensation network to stabilize control loop
5 FB	Feedback input	High-impedance input referenced to 1.235V; sets output via resistive divider
8 VCC	Internal bias supply	Unregulated input powering internal circuitry; must be bypassed with ≥10µF ceramic

Key Features

Feature	Design Value
Voltage feedforward	Compensates for input ripple without increasing loop gain variation - improves line regulation to ±0.5% over 4.4–36V
100% duty cycle operation	Enables ultra-low dropout mode - maintains regulation even when V_IN ≈ V_OUT, e.g., 5V→3.3V conversion
Pulse-by-pulse current limiting	Provides constant-current short-circuit protection without latch-off - sustains safe operation during transient faults
Zero-load current operation	Draws only 2.5mA quiescent current at no load - suitable for always-on system rails
Feedback disconnection protection	Shuts down switch if FB pin floats - prevents uncontrolled high-voltage output during open-divider failure

Applications

Consumer Audio Power Supply

Industrial DC-DC Converter

Use Scenario: Generating 3.3V/1.5A rail for audio DACs and amplifiers in car radio head units powered from 9–16V battery.

IC Role / Device Role / Timing Role: Primary buck regulator providing isolated, low-noise analog supply with tight line regulation.

Use Value: Voltage feedforward ensures <±0.5% output variation across battery swing; SO8 package fits compact PCB layouts.

Use Scenario: Building 5V/1.2A auxiliary supply from 24V industrial bus for PLC I/O modules.

IC Role / Device Role / Timing Role: High-input-voltage step-down regulator with robust thermal performance and fault protection.

Use Value: 36V max input rating and thermal shutdown enable reliable operation in unregulated 24V systems with ambient up to 70°C.

Computer Peripheral Power

Networking DC-DC Module

Use Scenario: Powering USB hub controllers and PHYs on PCIe audio/graphic cards from 5V slot power.

IC Role / Device Role / Timing Role: Compact 5V-to-1.8V/2.5V/3.3V point-of-load regulator with fast transient response.

Use Value: 250kHz fixed frequency allows small 33µH inductor; 2A switch handles peak USB load surges.

Use Scenario: Embedded 12V-to-3.3V supply in xDSL line card with space-constrained layout.

IC Role / Device Role / Timing Role: Efficient, low-profile buck converter meeting EMI Class B limits.

Use Value: Ceramic-capacitor compatible design reduces footprint vs. electrolytic-based solutions; SO8 aids automated assembly.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM2596-ADJ	3A switch, 150kHz fixed frequency, 1.23V reference, TO-220/SOIC-8 packaging	Higher current but lower switching frequency - requires larger inductor/capacitor	Select for higher output current (>1.5A) where board space permits larger magnetics
MP1584EN	3A switch, 1.5MHz fixed frequency, 0.8V reference, SOIC-8 packaging	Higher frequency enables smaller LC components but tighter layout constraints for EMI	Select for compact designs needing <10µH inductors and fast load transient response

Compared with LM2596-ADJ and MP1584EN, the L5972D offers superior line regulation via voltage feedforward, lower R_DS(on) at 250 mΩ, and proven reliability in 5V-bus consumer electronics - making it optimal for cost-sensitive, thermally constrained 2A-class buck applications.

Availability

L5972D is available at Aetrix Electronics and suitable for consumer audio power supplies, industrial DC-DC converters, and computer peripheral power rails requiring stable component supply, long-term lifecycle support, and RoHS-compliant SO8 packaging.

Supply support for L5972D 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, designing and manufacturing analog, power, microcontroller, and sensor solutions for industrial, automotive, and consumer markets.

The L5972D belongs to ST's monolithic DC-DC converter product line, engineered for high-efficiency, low-component-count buck regulation in cost-sensitive embedded power applications with wide input voltage ranges.

FAQ

What is the minimum input voltage required for regulation with the L5972D?

The L5972D requires a minimum input voltage of 4.4V to maintain regulation across its full output range. Below this threshold, the internal bias circuitry cannot sustain proper gate drive and error amplifier operation, resulting in dropout or shutdown. This makes it ideal for 5V bus systems but unsuitable for 3.3V-only inputs without a boost pre-regulator.

Can the L5972D operate with ceramic output capacitors only?

Yes - the L5972D is explicitly designed for low-ESR ceramic output capacitors, as confirmed by ST's demo board using 10µF ceramic (C1) and 100µF POSCAP (C2). Its Type II/III compensation via the COMP pin ensures stability with ceramic-only outputs, eliminating need for electrolytic or tantalum bulk capacitance.

How does the voltage feedforward function improve performance?

Voltage feedforward in the L5972D modulates PWM duty cycle in real time based on instantaneous V_CC, maintaining constant loop gain across 4.4–36V input range. This reduces line-induced output variation to ±0.5%, eliminates need for complex feedforward networks, and improves transient response to input voltage steps without compromising stability.

What thermal derating applies above 70°C ambient?

At T_A > 70°C, the L5972D's 1.2W maximum power dissipation (P_tot) must be reduced linearly per its 65°C/W junction-to-ambient thermal resistance. For example, at 100°C ambient, max allowable power drops to ~0.74W - limiting continuous output current to ~1.0A at 5V output, assuming typical efficiency and PCB copper area.

L5972D Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

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

Packaging:: Tube

Product Status:: Active

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):: 1.235V

Voltage - Output (Max):: 35V

Current - Output:: 2A

Frequency - Switching:: 250kHz

Synchronous Rectifier:: No

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

L5972D FAQ

1.How can I place an order for L5972D through Aetrix?

Please submit a Request for Quotation (RFQ) for L5972D 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 L5972D reliable?

The price and inventory of L5972D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L5972D is usually 5 days.

3.What payment methods are accepted for L5972D?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L5972D transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L5972D?

L5972D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L5972D 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 L5972D?

For technical support, including L5972D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L5972D requirements.

6.How does Aetrix verify that L5972D is sourced from the original manufacturer or authorized distributors?

All L5972D 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 L5972D meets industry standards.

7.What is the process for return or replacement of L5972D?

All L5972D units undergo pre-shipment inspection (PSI). If there is an issue with L5972D, 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 L5972D part is unused and in its original packaging.

Return procedure for L5972D:

1.Submit a request within 90 days.

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

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