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

STMicroelectronics A5970AD

Name: A5970AD
Brand: STMicroelectronics
SKU: A5970AD
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: A5970AD

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - DC DC Switching Regulators

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

Datasheet:: A5970AD.pdf

Description:: IC REG BUCK ADJ 1A 8SOIC

Quantity:: RFQ Add To RFQ list

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Inventory:1,225

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Product details

Overview

A5970AD 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, fixed 500 kHz switching frequency, and AEC-Q100 qualification for cold-crank operation in engine control units and body electronics.

For engineers reviewing the A5970AD datasheet, A5970AD pinout, A5970AD application, or A5970AD equivalent, this device supports adjustable output (1.235 V to V_IN), zero-load burst-mode operation, internal 3.3 V reference (±2%), synchronization capability, and thermal shutdown-key selection criteria for 12 V/24 V automotive subsystems requiring high reliability under wide temperature and load transients.

Technical Context

The A5970AD implements voltage-mode PWM control with an internal transconductance error amplifier (g_m = 2.3 mS, gain = 57 dB), fed by a 1.235 V feedback reference and driven by a sawtooth oscillator with voltage feed-forward. Its pulse-by-pulse current limiting (1.35 A min) and frequency foldback protect against short circuits without external sensing components.

It features dual protection architecture: feedback disconnection detection disables the regulator if FB floats, while overvoltage protection triggers at 1.3×(R1+R2)/R2 × V_FB. The inhibit function reduces quiescent current to ≤100 µA when INH > 2.2 V, and thermal shutdown activates at T_J = 150 °C ± 10 °C with 20 °C hysteresis.

Key Specifications

Parameter	Value and Actual Design Meaning
Output current	Up to 1 A DC - sufficient for powering microcontrollers, sensors, and CAN transceivers in automotive ECUs.
Input voltage range	4 V to 36 V - supports cold-crank (4.5 V) and load-dump (36 V) conditions per ISO 7637-2.
Switching frequency	500 kHz (±15%) - enables compact LC filter design with <10 µH inductors and low-ESR ceramic capacitors.
Reference voltage	3.3 V ±2% at VREF pin - stable bias source for external circuitry; 1.235 V ±2.9% at FB pin for output regulation.
R_DS(on)	250 mΩ (typ.) - minimizes conduction loss and thermal rise in SO-8 package at full load.
Quiescent current	5–7 mA operating / ≤100 µA standby - meets automotive idle-current requirements for always-on modules.
Protection features	Thermal shutdown, feedback disconnect disable, output overvoltage protection, pulse-by-pulse current limit - eliminates need for external fault management circuitry.

Pinout & Package

Package: SO-8 (small-outline integrated circuit, 8-pin, surface-mount, 1.27 mm pitch). Thermal resistance R_thJA = 120 °C/W on evaluation board.

Pin	Circuit Role	Design Meaning
1 OUT	Power switch output	Drives external inductor; connects to LC filter output node; handles peak currents up to 1.8 A.
2 SYNCH	Synchronization I/O	Configurable as master (output 2.75–3 V pulse) or slave (accepts 0.74–2.5 VREF sync signal); enables noise-free multi-rail coordination.
3 INH	Inhibit control input	Active-high logic: ≥2.2 V disables regulator and reduces I_q to ≤100 µA; internal pull-up ensures safe default-off state.
4 COMP	Error amplifier output	Connects to RC compensation network; sets loop stability and transient response; sinks up to 1.5 mA.
5 FB	Feedback input	Senses regulated output via resistive divider; internal 1.235 V reference defines V_OUT = 1.235 × (1 + R1/R2).
6 VREF	3.3 V reference output	Stable, low-noise supply for external analog circuitry; no capacitor required for stability.
7 GND	Analog/digital ground	Common return for feedback, reference, and control circuitry; must be routed separately from power ground in layout.
8 VCC	Unregulated input supply	Accepts raw battery rail (4–36 V); powers internal regulator and gate driver; requires local 100 nF decoupling.

Key Features

Feature	Design Value
Voltage feed-forward	Compensates for input line variations in real time, improving load transient response without increasing loop gain.
Zero-load burst mode	Operates without bootstrap capacitor; maintains regulation at no load via randomized burst frequency-critical for always-on telematics modules.
Internal P-channel MOSFET	Eliminates need for external high-side driver or bootstrap network, reducing BOM count and PCB area in space-constrained automotive modules.
Feedback disconnect protection	Automatically disables regulator if FB pin floats, preventing uncontrolled output voltage rise that could damage downstream loads.
Synchronization capability	Enables multiple A5970AD units to share one clock, eliminating beat-frequency EMI in multi-rail systems like ADAS domain controllers.

Applications

Engine Control Unit (ECU) Power Supply

Body Control Module (BCM) Rail Generator

Use Scenario: Powers 3.3 V microcontroller, CAN transceiver, and sensor interface in gasoline/diesel engine ECU under cold-crank (4.5 V) and load-dump (36 V) stress.

IC Role / Device Role / Timing Role: Primary buck regulator providing stable 3.3 V/1 A rail; operates continuously across -40 °C to +125 °C ambient with thermal foldback.

Use Value: AEC-Q100 qualification and 4–36 V input range ensure uninterrupted operation during cranking and alternator transients-no brownout resets.

Use Scenario: Generates 5 V rail for door module microcontrollers, LIN transceivers, and LED drivers in vehicle body electronics.

IC Role / Device Role / Timing Role: Adjustable-output buck converter (set to 5 V via FB divider); uses burst mode to maintain regulation at microamp sleep currents.

Use Value: ≤100 µA standby current and zero-load operation extend battery life in key-off monitoring states without auxiliary LDOs.

Advanced Driver Assistance Systems (ADAS) Camera Power

Infotainment System Core Voltage Regulator

Use Scenario: Supplies clean 1.2 V core voltage to image signal processor (ISP) in rear-view camera module mounted near exhaust.

IC Role / Device Role / Timing Role: High-efficiency buck regulator (90% at 5 V_IN/12 V_IN → 1.2 V); synchronized to system clock to suppress switching noise in analog video path.

Use Value: 500 kHz fixed frequency + sync pin enables deterministic EMI filtering; thermal shutdown prevents ISP latch-up at 105 °C junction.

Use Scenario: Provides 1.8 V core rail for application processor in head-unit infotainment system with variable load (100 mA–800 mA).

IC Role / Device Role / Timing Role: Adjustable buck regulator (1.235–V_IN) with internal compensation; uses voltage feed-forward to reject ripple from noisy 12 V battery bus.

Use Value: Feed-forward improves PSRR by >20 dB at 100 Hz–1 kHz, reducing audible noise in audio amplifiers powered from same battery rail.

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; 5 A rating; no AEC-Q100; 63 kHz switching; external N-MOSFET required.	Designed for industrial non-automotive use; lacks cold-crank support and sync capability.	Select only for cost-sensitive 5 V-only designs where automotive qualification and high-frequency operation are unnecessary.
MPQ4420AGL-AEC1-P	AEC-Q100 qualified; 2 A output; 2 MHz switching; integrated N-MOSFET; no internal VREF output.	Better suited for space-constrained ADAS cameras needing higher current and smaller inductors, but lacks dedicated 3.3 V reference for analog biasing.	Prefer when >1 A output or >1 MHz frequency is required; avoid if external 3.3 V reference for sensor biasing is needed.

Compared with LM2678-5.0/NOPB, A5970AD offers automotive qualification, wider input range, and integrated reference; versus MPQ4420AGL-AEC1-P, it trades higher current and frequency for lower EMI via 500 kHz and built-in VREF-making it optimal for mixed-signal automotive subsystems.

Availability

A5970AD is available at Aetrix Electronics and suitable for engine control units, body control modules, ADAS camera power supplies, and infotainment core voltage regulation requiring stable component supply across automotive production lifecycles.

Supply support for A5970AD 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, specializing in automotive-grade analog, power, and microcontroller solutions with vertical manufacturing and AEC-Q100 validation infrastructure.

The A5970AD belongs to ST's automotive power management IC portfolio, engineered specifically for robust DC-DC conversion in harsh-temperature, high-transient automotive environments-including start-stop systems and zone controllers.

FAQ

What is the minimum input voltage required for A5970AD to start regulation?

The A5970AD begins regulation at 4 V input, verified across -40 °C to +125 °C junction temperature. This enables reliable startup during automotive cold-crank events where battery voltage dips to 4.5 V, satisfying ISO 16750-2 pulse 4 requirements without external boost assist.

Can A5970AD operate without an external feedback resistor divider?

Yes-connecting the FB pin directly to the OUT pin configures the device for 1.235 V output. For any other voltage, a two-resistor divider is mandatory; floating FB triggers immediate shutdown to prevent overvoltage, per Section 6.1 of the datasheet.

How does the synchronization feature behave when multiple A5970AD devices are connected?

When SYNCH pins are tied together, the device with highest natural switching frequency (up to 570 kHz) becomes master and drives others as slaves. No external clock source is needed; all units lock to the master's 500 kHz ±15% frequency, eliminating beat-frequency EMI in multi-rail systems.

Is external compensation required for stable operation?

Yes-compensation is mandatory between COMP and GND using an RC network (e.g., 10 kΩ + 1 nF + 100 pF) to ensure phase margin >45° across load and temperature. The error amplifier's 2.3 mS transconductance and 57 dB gain require tailored compensation per output capacitor ESR and inductance values.

A5970AD 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:: 500kHz

Synchronous Rectifier:: No

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

Grade:: Automotive

Qualification:: AEC-Q100

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

A5970AD FAQ

1.How can I place an order for A5970AD through Aetrix?

Please submit a Request for Quotation (RFQ) for A5970AD 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 A5970AD reliable?

The price and inventory of A5970AD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A5970AD is usually 5 days.

3.What payment methods are accepted for A5970AD?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A5970AD transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for A5970AD?

A5970AD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your A5970AD 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 A5970AD?

For technical support, including A5970AD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A5970AD requirements.

6.How does Aetrix verify that A5970AD is sourced from the original manufacturer or authorized distributors?

All A5970AD 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 A5970AD meets industry standards.

7.What is the process for return or replacement of A5970AD?

All A5970AD units undergo pre-shipment inspection (PSI). If there is an issue with A5970AD, 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 A5970AD part is unused and in its original packaging.

Return procedure for A5970AD:

1.Submit a request within 90 days.

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

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