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

STMicroelectronics A5974DTR

Name: A5974DTR
Brand: STMicroelectronics
SKU: A5974DTR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: A5974DTR

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

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

Datasheet:: A5974DTR.pdf

Description:: IC REG BUCK ADJ 2.5A 8HSOP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

A5974DTR from STMicroelectronics is a monolithic step-down switching regulator IC designed for automotive power conversion, featuring an internal P-channel DMOS switch (R_DS(on) = 250 mΩ), 250 kHz fixed-frequency operation, and AEC-Q100 qualification. It delivers up to 2.5 A DC output current across 4 V–36 V input range, supports adjustable output from 1.235 V to 35 V, and enables cold-crank operation down to 4 V - ideal for engine control units and body electronics.

For engineers reviewing the A5974DTR datasheet, A5974DTR pinout, A5974DTR application, or A5974DTR equivalent, key selection criteria include its HSOP8 exposed-pad thermal performance (R_thJA ≈ 40 °C/W), synchronization capability, inhibit-controlled zero-load quiescent current (≤100 µA), and integrated short-circuit protection via pulse-by-pulse current limiting and frequency foldback.

Technical Context

The A5974DTR implements voltage-mode PWM control with feed-forward compensation, using an internal transconductance error amplifier (g_m = 2.3 mS, DC gain = 65 dB) and a sawtooth oscillator synchronized to an external clock or operating as master/slave via the SYNC pin. Its feedback loop references a precision 1.235 V bandgap (±2% over temperature) and supports dynamic compensation through the COMP pin.

Current protection combines cycle-by-cycle peak limiting (3.1 A min. switch current limit) with adaptive frequency reduction during overload, while thermal shutdown activates at 150 °C ±10 °C with ~20 °C hysteresis. The INH pin provides logic-level enable/disable with internal pull-up, supporting <100 µA standby current when asserted high.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	4 V to 36 V - supports automotive battery transients including cold-crank (4 V minimum).
Output Current	Up to 2.5 A DC - enabled by 3.1 A min. switch current limit and HSOP8 exposed-pad package (R_thJA ≈ 40 °C/W).
Switching Frequency	250 kHz (±15%) - fixed internal oscillator with optional synchronization to external clock or other A5974DTR devices.
Reference Voltage	1.235 V (±2%) - precise bandgap reference for FB pin; enables accurate output regulation across temperature.
Quiescent Current	≤100 µA in inhibit mode - ensures ultra-low power consumption during vehicle sleep states.
R_DS(on)	250 mΩ (typ.) - low on-resistance P-channel DMOS switch minimizes conduction losses and external component count.
Duty Cycle Range	0–100% - supports low-dropout operation, enabling output voltages near input rail (e.g., 35 V out at 36 V in).

Pinout & Package

Package: HSOP8 with exposed thermal pad (pin 9), optimized for automotive thermal management (R_thJA ≈ 40 °C/W on evaluation board).

Pin/Terminal	Circuit Role	Design Meaning
1 OUT	Power switch output	Connects directly to inductor; carries full switched output current (up to 2.5 A).
2 SYNC	Synchronization I/O	Configurable as master (output) or slave (input); enables noise-free multi-rail coordination at 250 kHz.
3 INH	Inhibit control input	Active-high logic enable; internal pull-up disables device if left floating; V_CC-compatible (0.8 V/2.2 V thresholds).
4 COMP	Error amplifier output	Drives external RC compensation network to stabilize feedback loop and ensure phase margin >45°.
5 FB	Feedback input	Resistive divider input referenced to 1.235 V; direct connection yields 1.235 V output; sets output voltage precisely.
6 VREF	3.3 V reference output	Stable 3.3 V supply (±3%); powers sync circuitry; requires ≥100 nF decoupling for master-mode synchronization.
7 GND	Analog/digital ground	Common return for control circuitry; must be connected to exposed pad for thermal and electrical integrity.
8 VCC	Unregulated input supply	Primary power input (4–36 V); powers internal regulator and gate driver; bypass with ≥10 µF ceramic capacitor.
9 EX-PAD	Thermal & electrical ground	Exposed copper pad; soldered to PCB ground plane to dissipate heat and reduce R_thJA to ~40 °C/W.

Key Features

Feature	Design Value
Voltage feed-forward compensation	Improves line transient response by scaling PWM ramp amplitude with input voltage - reduces output deviation during battery dips.
Pulse-by-pulse current limiting	Monitors switch current each cycle; forces immediate turn-off at 3.1 A threshold - prevents MOSFET destruction during short circuits.
Frequency foldback under overload	Reduces switching frequency as feedback voltage drops - maintains inductor current below safe limit when duty cycle alone is insufficient.
Feedback disconnection protection	Detects open FB trace or resistor failure; clamps duty cycle to prevent uncontrolled output rise toward input rail.
Zero-load operation	Maintains regulation with no output load - critical for always-on automotive modules (e.g., CAN gateway, alarm controller).

Applications

Engine Control Unit (ECU) Power Supply

Automotive Infotainment Core Rail

Use Scenario: Supplies 5 V/2.5 A to microcontroller, CAN transceivers, and sensor interfaces in gasoline/diesel ECUs exposed to 4–16 V battery swings and cold-crank events.

IC Role / Device Role / Timing Role: Primary buck regulator delivering stable core voltage; operates continuously across -40 °C to +125 °C ambient.

Use Value: 250 kHz switching enables compact LC filter (15 µH + 330 µF); AEC-Q100 qualification ensures reliability in safety-critical engine management.

Use Scenario: Generates 3.3 V for SoC, display controller, and audio codec in head unit systems requiring low EMI and fast load-step response.

IC Role / Device Role / Timing Role: Secondary buck converter synchronized to main system clock to eliminate beat frequencies between multiple rails.

Use Value: SYNC pin allows deterministic phase alignment with other regulators; feed-forward improves transient suppression during video frame bursts.

Body Control Module (BCM) Subsystem

Advanced Driver Assistance Systems (ADAS) Camera Power

Use Scenario: Powers door lock actuators, window lift motors, and LED lighting drivers in BCMs where low quiescent current extends battery life during vehicle sleep.

IC Role / Device Role / Timing Role: Always-on buck regulator with INH pin controlled by microcontroller wake signal; enters <100 µA standby when inactive.

Use Value: Inhibit function eliminates parasitic drain; 100% duty cycle supports 12 V → 11.5 V dropout for auxiliary loads without external LDO.

Use Scenario: Provides 1.8 V/2 A to CMOS image sensor and ISP in rear-view or surround-view cameras mounted in hot under-hood environments.

IC Role / Device Role / Timing Role: High-reliability buck converter with thermal shutdown (150 °C) and robust short-circuit protection for unattended camera operation.

Use Value: Exposed-pad HSOP8 package sustains 2.5 A at junction temperatures up to 150 °C; R_DS(on) stability ensures consistent output under thermal stress.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM2596T-ADJ	Fixed 150 kHz frequency; no synchronization; 3 A typical output but not AEC-Q100 qualified; TO-220 package (R_thJA > 60 °C/W).	Targeted at industrial/non-automotive designs; lacks cold-crank support (min. 4.5 V input) and automotive thermal robustness.	Select only for cost-sensitive non-automotive applications where AEC-Q100 and thermal performance are not required.
MPQ4420AGL-A	2.5 A rated; 35 V max input; AEC-Q100 Grade 1; 500 kHz switching; QFN-10 package with exposed pad (R_thJA ≈ 35 °C/W).	Higher frequency enables smaller magnetics; no internal VREF pin; requires external reference for feedback divider.	Prefer for space-constrained ADAS modules needing higher switching frequency and tighter thermal resistance - but verify compensation design for 500 kHz loop.

Compared with LM2596T-ADJ, A5974DTR offers automotive-grade reliability, cold-crank operation, and superior thermal performance; versus MPQ4420AGL-A, it provides integrated 3.3 V VREF and simpler feedback configuration at the cost of lower switching frequency and larger external components.

Availability

A5974DTR is available at Aetrix Electronics and suitable for engine control units, infotainment systems, and body control modules requiring stable component supply across automotive production lifecycles.

Supply support for A5974DTR 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, microcontroller, power, and automotive ICs for industrial and transportation markets.

The A5974DTR belongs to ST's automotive-grade power management portfolio, engineered specifically for harsh-environment DC-DC conversion in vehicles - emphasizing AEC-Q100 compliance, thermal resilience, and functional safety readiness.

FAQ

What is the minimum input voltage required for A5974DTR to regulate during cold-crank conditions?

The A5974DTR operates down to 4 V input, enabling continuous regulation during automotive cold-crank events where battery voltage can dip to 3.5–4.0 V. This is achieved via low-threshold UVLO and 100% duty cycle capability, allowing output voltages close to the input rail without dropout.

How does the SYNC pin function in master vs. slave configuration?

When multiple A5974DTR devices share a SYNC net, the one with highest natural switching frequency (250 kHz ±15%) becomes master and drives the net; others operate as slaves synchronized to that frequency. As master, the SYNC pin outputs a 2.75–3 V square wave; as slave, it accepts 0.74–2.5 V input with 0.11–0.45 mA drive capability.

Can A5974DTR operate with no output load, and what is its quiescent behavior?

Yes - A5974DTR supports zero-load operation with stable regulation. In active mode, total operating quiescent current is 3–5 mA; when INH is pulled high (>2.2 V), standby current drops to ≤100 µA, meeting automotive "always-on" module requirements for extended parking modes.

What thermal derating guidance applies when using A5974DTR at 2.5 A output?

At 2.5 A output and 12 V input, power dissipation is ~0.6 W. With R_thJA ≈ 40 °C/W on a standard 4-layer board, junction temperature rise is ~24 °C above ambient. To stay within 150 °C max T_J, ambient must remain ≤126 °C - achievable with proper copper pour and airflow in engine bay mounting.

A5974DTR 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:: Obsolete

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:: Automotive

Qualification:: AEC-Q100

Mounting Type:: Surface Mount

Supplier Device Package:: 8-HSOP-EP

A5974DTR FAQ

1.How can I place an order for A5974DTR through Aetrix?

Please submit a Request for Quotation (RFQ) for A5974DTR 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 A5974DTR reliable?

The price and inventory of A5974DTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A5974DTR is usually 5 days.

3.What payment methods are accepted for A5974DTR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A5974DTR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for A5974DTR?

A5974DTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your A5974DTR 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 A5974DTR?

For technical support, including A5974DTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A5974DTR requirements.

6.How does Aetrix verify that A5974DTR is sourced from the original manufacturer or authorized distributors?

All A5974DTR 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 A5974DTR meets industry standards.

7.What is the process for return or replacement of A5974DTR?

All A5974DTR units undergo pre-shipment inspection (PSI). If there is an issue with A5974DTR, 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 A5974DTR part is unused and in its original packaging.

Return procedure for A5974DTR:

1.Submit a request within 90 days.

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

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