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

STMicroelectronics B5973DTR

Name: B5973DTR
Brand: STMicroelectronics
SKU: B5973DTR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: B5973DTR

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

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

Datasheet:: B5973DTR.pdf

Description:: IC REG BUCK ADJ 2A 8HSOP

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Product details

Overview

B5973DTR from STMicroelectronics is an AEC-Q100 Grade 1 qualified monolithic step-down switching regulator for automotive power systems, featuring a 2.25 A minimum switch current limit, 4 V to 36 V input range, and adjustable output from 1.235 V to 35 V. It integrates a P-channel DMOS switch (R_DS(on) = 250 mΩ typ), operates at 250 kHz fixed frequency, and supports zero-load operation with inhibit control.

For engineers reviewing the B5973DTR datasheet, B5973DTR pinout, B5973DTR application, or B5973DTR equivalent, key selection criteria include its automotive qualification, thermal resistance (R_thJA ≈ 40 °C/W in HSOP8), internal 3.3 V reference (±2 %), voltage feedforward architecture, and synchronization capability for multi-regulator systems.

Technical Context

The B5973DTR implements a voltage-mode PWM controller with internal P-channel MOSFET, enabling high-side switching without external high-side driver. Its voltage feedforward compensation improves line transient response, while pulse-by-pulse current limiting with frequency modulation delivers robust short-circuit protection across temperature.

It supports master/slave synchronization via the SYNCH pin, allows full 100 % duty cycle for low-dropout operation, and features an internal error amplifier with COMP pin for external loop compensation. The device operates down to 4 V input-making it suitable for 5 V bus systems-and maintains regulation under zero-load conditions via active bias management.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Voltage Range	4 V to 36 V - enables direct connection to automotive battery rails including cold-crank (4 V) and load-dump (36 V) conditions.
Output Current Capability	Up to 2 A DC - limited by thermal design and external component selection; supported by SO8 exposed-pad package (R_thJA ≈ 40 °C/W).
Switching Frequency	250 kHz (fixed) - balances EMI performance and inductor size; internally generated, not externally programmable.
Reference Voltage	3.3 V ±2 % - stable internal reference used for feedback and regulation; no external capacitor required.
Feedback Threshold	1.235 V - sets base output voltage when FB pin connected directly to output; enables precise resistor-divider programming.
Quiescent Current	3–5 mA (operating), 50–150 μA (standby) - ensures low system power loss during sleep modes in automotive ECUs.
Thermal Shutdown	Active at T_J > 150 °C - protects device under overload or poor heatsinking; auto-recovery on cooldown.

Pinout & Package

Package: HSOP8 with exposed thermal pad (JEDEC MO-187 variant), lead-free ECOPACK® compliant, R_thJA = 40 °C/W when mounted per recommended layout.

Pin/Terminal	Circuit Role	Design Meaning
OUT	Power switch drain node	Connects to inductor and freewheeling diode; carries high-frequency pulsed current up to 2.25 A peak.
SYNCH	Master/slave sync interface	Accepts or outputs 250 kHz square wave for timing alignment with other regulators; bidirectional function.
INH	Enable/disable logic input	Active-high inhibit: >2.2 V disables regulator and reduces I_qst-by to ≤150 μA; open or floating disables via internal pull-up.
COMP	Error amplifier output	Provides compensation node for external Type II/III network; sets loop stability and transient response.
FB	Voltage feedback input	Senses output via resistive divider; regulates when voltage equals 1.235 V; high-impedance input (I_b = 2.5–4 μA).
VREF	Internal 3.3 V reference output	Stable, low-noise reference for external circuitry or auxiliary bias; no bypass cap needed.
GND	Analog and power ground	Common return for feedback, reference, and control circuits; must be tied to thermal pad for optimal thermal performance.
VCC	Unregulated input supply	Powers internal circuitry; accepts same 4–36 V input as main VIN; decoupling capacitor required at pin.

Key Features

Feature	Design Value
AEC-Q100 Grade 1 qualification	Validated for automotive ambient temperatures from −40 °C to +125 °C; PPAP documentation available.
Zero-load operation	Maintains regulation with no output current draw-critical for always-on vehicle modules like CAN gateways.
Voltage feedforward control	Compensates for input voltage transients without waiting for output error, improving line regulation speed.
Internal P-channel MOSFET	Eliminates need for external high-side driver; reduces BOM count and layout complexity in buck topologies.
Feedback disconnection protection	Detects open FB trace or resistor failure and forces shutdown-prevents uncontrolled overvoltage output.

Applications

Infotainment Power Supply

ADAS Camera Module

Use Scenario: Powering SoC core and I/O rails in head-unit systems requiring clean, efficient 1.2 V and 3.3 V supplies from 12 V battery.

IC Role / Device Role / Timing Role: Primary buck regulator delivering up to 2 A at adjustable output; provides stable voltage under wide input transients (cold crank/load dump).

Use Value: AEC-Q100 qualification ensures reliability in dashboard environments; 250 kHz switching enables compact magnetics and meets CISPR-25 Class 5 EMI limits.

Use Scenario: Generating 5 V and 3.3 V rails for image sensor, ISP, and serializer in rear-view or surround-view camera ECU.

IC Role / Device Role / Timing Role: High-efficiency synchronous buck controller supporting zero-load standby for wake-on-event functionality.

Use Value: 50–150 μA standby current extends battery life during vehicle off-state; inhibit pin enables deep-sleep control via MCU GPIO.

Body Control Module (BCM)

Telematics Control Unit (TCU)

Use Scenario: Regulating 5 V for microcontroller, CAN transceivers, and sensor interfaces in door module or lighting control unit.

IC Role / Device Role / Timing Role: Main 5 V power source with integrated current limiting and thermal shutdown-replaces discrete FET + controller solutions.

Use Value: Internal 2.25 A current limit and 100 % duty cycle support direct 5 V output from 12 V nominal; reduces external component count by ≥30 %.

Use Scenario: Providing isolated 3.3 V and 1.8 V supplies for LTE modem, GNSS receiver, and secure element in cellular-connected TCU.

IC Role / Device Role / Timing Role: Primary buck stage feeding secondary LDOs; synchronized via SYNCH pin to avoid beat frequencies with RF sections.

Use Value: Master/slave sync capability eliminates switching noise coupling into sensitive RF bands; 3.3 V reference supports accurate ADC biasing.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM2678SD-ADJ/NOPB	5 A rated, 60 V max input, no AEC-Q100 qualification, requires external N-MOSFET	Industrial/non-automotive use only; higher current but larger solution size due to external FET	Select if >2 A output or >36 V input is required; not suitable for automotive production without requalification.
TPS54202DR	2 A rated, 6–17 V input, integrated N-MOSFET, no internal VREF, no sync pin	Lacks automotive qualification and synchronization; optimized for cost-sensitive consumer power rails	Choose for non-automotive 12 V systems where footprint and BOM cost are prioritized over thermal performance and sync capability.

Compared with LM2678SD-ADJ/NOPB and TPS54202DR, the B5973DTR uniquely combines AEC-Q100 Grade 1 compliance, internal P-MOSFET, 250 kHz sync capability, and 4–36 V input range-making it the only drop-in solution for thermally constrained, safety-critical automotive buck stages requiring zero-load operation and feedback fault protection.

Availability

B5973DTR is available at Aetrix Electronics and suitable for automotive infotainment systems, ADAS camera modules, and body control units requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for B5973DTR 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 silicon solutions for automotive, industrial, and consumer markets since 1987.

The B5973DTR belongs to ST's automotive-grade power management IC portfolio, engineered specifically for robust, high-reliability DC-DC conversion in engine bay, cabin, and ADAS subsystems operating under harsh electrical and thermal conditions.

FAQ

What is the maximum junction temperature and thermal shutdown behavior of the B5973DTR?

The B5973DTR has a maximum operating junction temperature of 150 °C. Thermal shutdown activates above this threshold, halting switching and reducing power dissipation until junction temperature falls below hysteresis level (~140 °C). Recovery is automatic and does not require reset or power cycle.

Can the B5973DTR operate with input voltage below 5 V, and what is the minimum functional input?

Yes-the B5973DTR operates down to 4 V input, making it compatible with automotive cold-crank conditions. At 4 V, it sustains regulation at reduced output current due to duty-cycle limitation; full 2 A output is achievable above ~5.5 V depending on output voltage setting and thermal margin.

Is an external compensation network required on the COMP pin, and what topology is supported?

Yes-an external Type II or Type III compensation network is mandatory on the COMP pin to ensure loop stability. ST recommends a series RC parallel with C network between COMP and FB; exact values depend on output voltage, inductance, and output capacitance, and are detailed in AN2083 application note.

Does the B5973DTR support forced continuous conduction mode (FCCM), and how is it configured?

No-the B5973DTR operates in standard voltage-mode PWM with discontinuous conduction mode (DCM) at light loads. FCCM is not supported; however, zero-load operation is maintained via active bias control, and the device remains regulated without entering burst mode or skipping cycles.

B5973DTR 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:: 2A

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

B5973DTR FAQ

1.How can I place an order for B5973DTR through Aetrix?

Please submit a Request for Quotation (RFQ) for B5973DTR 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 B5973DTR reliable?

The price and inventory of B5973DTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for B5973DTR is usually 5 days.

3.What payment methods are accepted for B5973DTR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for B5973DTR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for B5973DTR?

B5973DTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your B5973DTR 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 B5973DTR?

For technical support, including B5973DTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your B5973DTR requirements.

6.How does Aetrix verify that B5973DTR is sourced from the original manufacturer or authorized distributors?

All B5973DTR 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 B5973DTR meets industry standards.

7.What is the process for return or replacement of B5973DTR?

All B5973DTR units undergo pre-shipment inspection (PSI). If there is an issue with B5973DTR, 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 B5973DTR part is unused and in its original packaging.

Return procedure for B5973DTR:

1.Submit a request within 90 days.

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

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