STMicroelectronics A5972D

Overview

A5972D from STMicroelectronics is a monolithic step-down switching regulator IC designed for automotive power systems, featuring an internal P-channel DMOS switch (R_DS(on) = 250 mΩ typ.), 1.5 A DC output current capability, 4–36 V input voltage range, and fixed 250 kHz switching frequency - deployed in engine control units, infotainment power rails, and ADAS camera modules.

For engineers reviewing the A5972D datasheet, A5972D pinout, A5972D application, or A5972D equivalent, key selection criteria include cold-crank operation down to 4 V, AEC-Q100 qualification, feedback disconnection protection, zero-load burst-mode operation, and adjustable output from 1.235 V to V_IN.

Technical Context

The A5972D implements voltage-mode PWM control with feedforward compensation, using an internal transconductance error amplifier (G_m = 2.3 mS) referenced to a 1.235 V bandgap. Its 250 kHz oscillator integrates voltage feedforward to maintain constant PWM gain across input variations, improving line regulation and transient response.

Protection architecture includes dual current limiting (pulse-by-pulse + frequency foldback), thermal shutdown at 150 °C ±10 °C with 20 °C hysteresis, feedback disconnection detection, and output overvoltage protection triggered at 1.3×V_FB. The device operates in 100% duty cycle low-dropout mode and supports zero-load burst-mode operation without external bootstrap components.

Key Specifications

Pinout & Package

Package: SO-8 (small-outline integrated circuit, 8-pin, surface-mount, standard JEDEC MS-012AC). Pin assignments are validated per STMicroelectronics DocID13956 Rev 8, Section 1.2.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2678SD-5.0/NOPB and TPS54331DR, the A5972D uniquely combines AEC-Q100 qualification, cold-crank capability (4 V min), integrated P-MOSFET, and feedback disconnect protection - making it the only drop-in solution for safety-critical automotive buck stages requiring zero-footprint reliability.

Availability

A5972D is available at Aetrix Electronics and suitable for engine control units, ADAS camera modules, infotainment core rails, and body control module subsystems requiring stable component supply across extended automotive temperature and lifecycle demands.

Supply support for A5972D 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, industrial, and power management ICs with vertical manufacturing and AEC-Q100-aligned quality systems.

The A5972D belongs to ST's automotive-grade monolithic buck regulator product line, engineered specifically for under-hood and cabin electronics requiring robustness against voltage transients, thermal stress, and long-term reliability in harsh environments.

FAQ

What is the minimum input voltage required for A5972D startup and regulation?

The A5972D starts switching and regulates output at V_CC ≥ 4 V, verified across -40 °C to +125 °C ambient per AEC-Q100 testing. Below 4 V, UVLO disables the regulator to prevent unstable operation - enabling reliable function during automotive cold-crank events where battery voltage dips to ~3.5 V temporarily.

How does the A5972D handle feedback pin disconnection?

When the FB pin is left floating or disconnected, the A5972D detects loss of feedback voltage and immediately disables the power switch to prevent uncontrolled 100% duty cycle and potential overvoltage damage to downstream loads - a hardware-level safety feature confirmed in functional test reports.

Can the A5972D operate with no load connected to its output?

Yes - the A5972D enters burst-mode operation at zero load, maintaining output regulation without external bias or auxiliary winding. Quiescent current drops to 2.5 mA, and switching occurs in randomized bursts to minimize standby power dissipation in always-on automotive subsystems.

What thermal derating applies to the A5972D at elevated ambient temperatures?

With R_thJA = 65 °C/W on a standard evaluation board, the A5972D delivers full 1.5 A output up to T_A = 70 °C. Above that, output current must be linearly reduced to maintain T_J ≤ 150 °C; at 105 °C ambient, maximum continuous output is ~0.9 A with adequate copper area and airflow.