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

STMicroelectronics A5970D

Name: A5970D
Brand: STMicroelectronics
SKU: A5970D
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: A5970D

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

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

Datasheet:: A5970D.pdf

Description:: IC REG BUCK ADJ 1A 8SOIC

Quantity:: RFQ Add To RFQ list

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Product details

Overview

A5970D from STMicroelectronics is a monolithic step-down switching regulator IC designed for automotive power conversion, integrating a P-channel DMOS switch (R_DS(on) = 250 mΩ typ.), delivering up to 1 A DC output current with input voltage range 4–36 V and fixed 250 kHz switching frequency. It features AEC-Q100 qualification, 3.3 V reference (±2%), adjustable output (1.235 V to V_IN), and zero-load burst-mode operation - deployed in engine control units and body electronics requiring cold-crank resilience.

For engineers reviewing the A5970D datasheet, A5970D pinout, A5970D application, or A5970D equivalent, key selection criteria include its 1.35 A minimum current limit, thermal shutdown at 150 °C ±10 °C, synchronization capability via bidirectional SYNCH pin, and feedback disconnection protection - all critical for functional safety-compliant 12 V/24 V automotive subsystems.

Technical Context

The A5970D employs voltage-mode PWM control with an internal transconductance error amplifier (g_m = 2.3 mS, gain = 65 dB) referenced to a precision 1.235 V FB threshold and a 3.3 V VREF rail. Its oscillator integrates voltage feedforward to improve line transient response and supports master/slave synchronization via a single bidirectional pin operating at 250 kHz ±15%.

Protection architecture combines pulse-by-pulse current limiting (with 1.35–2.25 A min/max trip) and frequency foldback during overcurrent, plus thermal shutdown (150 °C ±10 °C), inhibit-controlled standby (<100 µA), and feedback-disconnection detection - enabling robust operation across -40 °C to +125 °C junction temperature.

Key Specifications

Parameter	Value and Actual Design Meaning
Output current	Up to 1 A DC load current; limited by internal 1.35 A min switch current threshold and thermal design margin.
Input voltage range	4 V to 36 V DC; supports automotive cold-crank (4 V) and load-dump (36 V) conditions without external protection.
Switching frequency	250 kHz fixed (212–280 kHz over temp); enables compact magnetics and predictable EMI filtering.
Reference voltage	3.3 V ±2% at VREF pin; supplies internal circuitry and serves as stable bias for external compensation.
Feedback threshold	1.235 V (1.198–1.272 V over temp); sets regulated output when FB connected directly to VOUT.
R_DS(on)	250 mΩ typical (0.25–0.5 Ω max); reduces conduction loss and simplifies thermal layout in SO-8 package.
Quiescent current	3–5 mA operating; drops to 50–150 µA in inhibit mode - critical for always-on vehicle modules.

Pinout & Package

Package: SO-8 (Small Outline, 8-pin, surface-mount, standard JEDEC MS-012AC footprint with exposed thermal pad).

Pin/Terminal	Circuit Role	Design Meaning
1 OUT	Power output node	Switched output of internal P-MOSFET; connects to LC filter inductor and output capacitor.
2 SYNCH	Synchronization I/O	Bidirectional pin for master/slave sync; accepts external clock ≥275 kHz or outputs 2.75–3 V sync signal.
3 INH	Inhibit control input	Active-high logic enable; >2.2 V disables device (I_Q < 100 µA); internal pull-up disables if floating.
4 COMP	Error amplifier output	Transconductance amplifier output; connects to RC network for loop stability compensation.
5 FB	Voltage feedback input	Senses output via resistive divider; 1.235 V threshold sets regulation point.
6 VREF	Internal reference output	3.3 V ±2% supply for bias and sync circuitry; requires ≥100 nF decoupling to GND for sync stability.
7 GND	Power and signal ground	Common return for power stage, analog blocks, and compensation network; ties to thermal pad.
8 VCC	Main power input	Unregulated DC input (4–36 V); powers internal regulator and gate driver; not current-limited externally.

Key Features

Feature	Design Value
AEC-Q100 qualified	Qualified per Grade 1 (-40 °C to +125 °C ambient), including PPAP documentation support for automotive OEMs.
Zero-load burst mode	Operates without bootstrap capacitor; enters random-frequency burst mode at no load to maintain regulation and low I_Q.
Voltage feedforward	Improves line transient response by scaling ramp amplitude with V_IN, reducing output deviation during input steps.
Feedback disconnection protection	Shuts down output if FB pin floats - prevents uncontrolled high-duty-cycle condition and potential load damage.
Thermal shutdown with hysteresis	Disables switching at T_J = 150 °C ±10 °C; restarts only after ~130 °C cooldown, preventing thermal oscillation.

Applications

Engine Control Unit (ECU) Power Rail

Automotive Infotainment Core Supply

Use Scenario: Powers microcontroller, CAN transceiver, and sensor interface in gasoline/diesel engine management systems under wide input transients.

IC Role / Device Role / Timing Role: Primary 5 V or 3.3 V buck regulator; provides stable, AEC-Q100-compliant power with cold-crank hold-up down to 4 V.

Use Value: Eliminates need for external current-sense resistor or discrete MOSFET driver; reduces BOM count by 4 components vs. controller+MOS solution.

Use Scenario: Supplies core logic voltage (1.2 V or 1.8 V) to SoC in head-unit or digital cluster with variable load profiles.

IC Role / Device Role / Timing Role: Adjustable-output buck converter synchronized to other rails via shared SYNCH net to suppress beat-frequency noise.

Use Value: Enables deterministic EMI profile through frequency lock; burst-mode operation maintains regulation during display sleep states.

Body Control Module (BCM) Subsystem

ADAS Camera Power Management

Use Scenario: Delivers 5 V to door module MCU and LIN transceivers in battery-powered body electronics.

IC Role / Device Role / Timing Role: Always-on buck regulator with inhibit control; enters ultra-low-I_Q standby (<100 µA) during vehicle sleep mode.

Use Value: Meets ISO 16750-2 quiescent current requirements for extended parking; eliminates need for external enable FET.

Use Scenario: Powers image sensor and ISP in rear-view or surround-view camera modules exposed to under-hood temperatures.

IC Role / Device Role / Timing Role: High-reliability buck regulator with thermal shutdown and overvoltage protection (OVP = 1.3 × V_FB).

Use Value: Prevents sensor latch-up during hot-plug events; OVP triggers before 5.5 V, protecting 3.3 V-rated CMOS imaging sensors.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM2678-5.0/NOPB	Fixed 5 V output; no adjustable FB, no SYNC, no AEC-Q100 qualification; R_DS(on) = 200 mΩ.	Targeted at industrial non-automotive use; lacks cold-crank support (min V_IN = 8 V) and inhibit function.	Select only for cost-sensitive non-automotive designs where 5 V fixed output suffices and qualification is unnecessary.
TPS54331DR	3.5 A current rating; adjustable frequency (100–2500 kHz); no AEC-Q100; uses N-MOSFET requiring bootstrap.	Higher-power applications needing >1 A; lacks integrated thermal shutdown hysteresis and feedback disconnect protection.	Choose when higher output current or programmable frequency is required, but accept added external components and no automotive qualification.

Compared with LM2678-5.0/NOPB and TPS54331DR, the A5970D uniquely combines AEC-Q100 compliance, cold-crank operation (4 V), and integrated protections - making it the only drop-in solution for ASIL-B–aligned automotive subsystems requiring <1 A output.

Availability

A5970D 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 A5970D 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, specializing in automotive, industrial, and power management ICs with broad manufacturing scale and automotive qualification expertise.

The A5970D belongs to ST's automotive-grade monolithic buck regulator product line, engineered specifically for under-hood and chassis-mounted applications demanding AEC-Q100 reliability, wide-input resilience, and integrated protection.

FAQ

What is the minimum input voltage required for A5970D startup under cold-crank conditions?

The A5970D starts switching at 4 V input, verified across -40 °C to +125 °C junction temperature. This meets ISO 16750-2 cold-crank specification for 12 V systems, ensuring uninterrupted operation during engine cranking when battery voltage dips to 4–6 V. Startup is guaranteed even with full load applied at turn-on.

How does the A5970D handle feedback disconnection, and what is the failure mode?

If the FB pin is left floating or disconnected, the A5970D detects open-loop condition and forces shutdown within 10 µs, clamping OUT at low impedance. This prevents uncontrolled 100% duty cycle that would drive output toward V_IN and damage downstream loads - a hardware-level safety feature independent of software or external supervision.

Can the A5970D be synchronized to an external clock, and what are the amplitude requirements?

Yes - the SYNCH pin accepts external TTL/CMOS clocks ≥275 kHz (minimum guaranteed natural f_SW + margin). Input amplitude must be 0.74 V (low) to 2.5 × VREF (high), i.e., 0.74–8.25 V for VCC = 36 V. A ≥100 nF capacitor between VREF and GND is mandatory for stable sync operation across temperature.

What is the thermal resistance (R_thJA) of the A5970D in SO-8, and how does it impact maximum output current?

R_thJA is 120 °C/W when mounted on a standard 2-layer evaluation board. At 125 °C max junction temperature and 25 °C ambient, this limits continuous power dissipation to 0.83 W. With typical 90% efficiency at 5 V/1 A, power loss is ~0.56 W - confirming 1 A output is thermally sustainable without forced airflow or copper pour enhancements.

A5970D Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

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

Packaging:: Tube

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):: 36V

Current - Output:: 1A

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-SOIC

A5970D FAQ

1.How can I place an order for A5970D through Aetrix?

Please submit a Request for Quotation (RFQ) for A5970D 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 A5970D reliable?

The price and inventory of A5970D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A5970D is usually 5 days.

3.What payment methods are accepted for A5970D?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A5970D transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for A5970D?

A5970D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your A5970D 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 A5970D?

For technical support, including A5970D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A5970D requirements.

6.How does Aetrix verify that A5970D is sourced from the original manufacturer or authorized distributors?

All A5970D 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 A5970D meets industry standards.

7.What is the process for return or replacement of A5970D?

All A5970D units undergo pre-shipment inspection (PSI). If there is an issue with A5970D, 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 A5970D part is unused and in its original packaging.

Return procedure for A5970D:

1.Submit a request within 90 days.

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

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