STMicroelectronics A5975ADTR

Overview

A5975ADTR 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), 2.5 A DC output current capability, 4–36 V input range, and fixed 500 kHz switching frequency. It delivers regulated output voltages from 1.235 V to 35 V and supports cold-crank operation down to 4 V input.

For engineers reviewing the A5975ADTR datasheet, A5975ADTR pinout, A5975ADTR application, or A5975ADTR equivalent, key selection criteria include AEC-Q100 qualification, thermal resistance of 40 °C/W in HSOP8 exposed-pad package, voltage feed-forward architecture, synchronization capability, and zero-load quiescent current of 50–100 µA in inhibit mode.

Technical Context

The A5975ADTR integrates a transconductance error amplifier (g_m = 2.3 mS, DC open-loop gain = 50–65 dB), pulse-by-pulse current limiting with frequency shifting during overcurrent, and a sawtooth oscillator with voltage feed-forward for improved line regulation. Its internal 3.3 V reference (±2% tolerance) feeds both the feedback comparator and external sync circuitry.

It implements dual protection layers: feedback disconnection detection prevents unregulated runaway, while thermal shutdown activates at T_J = 150 °C ±10 °C. The inhibit function enables true zero-current standby (I_qst-by ≤ 100 µA), and the SYNCH pin operates bidirectionally as master or slave for multi-rail noise reduction.

Key Specifications

Pinout & Package

Package: HSOP8 with exposed thermal pad (R_THJ-A ≈ 40 °C/W on demo board). Pinout defined per STMicroelectronics DocID018761 Rev 2, Table 1 and Figure 2.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM2678SDX-5.0/NOPB and TPS54240DGQR, the A5975ADTR uniquely combines AEC-Q100 qualification, integrated P-MOS, cold-crank operation, and bidirectional sync-all in a thermally optimized HSOP8 package-making it optimal for space-constrained, safety-critical automotive buck applications.

Availability

A5975ADTR is available at Aetrix Electronics and suitable for automotive infotainment systems, ADAS camera modules, and body control modules requiring stable component supply, AEC-Q100 compliance, and thermal robustness in harsh environments.

Supply support for A5975ADTR 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 solutions with broad manufacturing and quality infrastructure.

The A5975ADTR belongs to ST's automotive-grade monolithic DC-DC regulator product line, engineered specifically for reliable, high-current step-down conversion in engine bay and cabin electronics under wide temperature and voltage stress.

FAQ

What is the minimum input voltage required for A5975ADTR to regulate properly?

The A5975ADTR maintains regulation down to 4 V input, enabling operation during automotive cold-crank events where battery voltage dips below 6 V. This is achieved via low-dropout architecture supporting 100% duty cycle and internal pre-regulator optimization for low-V_IN startup.

Does A5975ADTR require an external compensation network?

Yes-the COMP pin is the transconductance error amplifier output and requires an external RC network (typically R-C series from COMP to FB, plus optional C from COMP to GND) to stabilize the control loop. ST provides recommended values in Section 7.1 of the datasheet based on output capacitance and inductance.

How does the synchronization feature work between multiple A5975ADTR devices?

The SYNCH pin operates bidirectionally: when tied together, the device with the highest natural switching frequency becomes the master and drives the shared sync line; others act as slaves locked to that frequency. No external clock source is needed, and a 100 nF capacitor on VREF improves sync signal integrity.

Can A5975ADTR be used in non-automotive applications?

Yes-its 4–36 V input range, 2.5 A output, and robust protections make it suitable for industrial power supplies and telecom equipment. However, AEC-Q100 qualification adds cost and test overhead; for non-automotive use, alternatives like TPS54240 may offer better value if automotive reliability is not required.