STMicroelectronics A5975DTR

Overview

A5975DTR from STMicroelectronics is a monolithic step-down switching regulator IC qualified to AEC-Q100 for automotive use, featuring 3 A DC output current, 4–36 V input range, and adjustable 1.235–35 V output voltage. It integrates a P-channel DMOS switch (R_DS(on) = 250 mΩ typ), operates at fixed 250 kHz, supports synchronization, and delivers full-duty-cycle low-dropout operation down to 4 V input-enabling reliable cold-crank performance in engine control units and ADAS power supplies.

For engineers reviewing the A5975DTR datasheet, A5975DTR pinout, A5975DTR application, or A5975DTR equivalent, this page provides verified technical context, HSOP8 package mapping, automotive-grade thermal and protection specifications, and real-world design implications for buck converter implementation in 12 V/24 V vehicle systems.

Technical Context

The A5975DTR implements voltage-mode PWM control with internal feed-forward compensation and a transconductance error amplifier (g_m = 2.3 mS, open-loop gain = 50–65 dB). Its oscillator generates a fixed 250 kHz sawtooth waveform, modulated via frequency-shifting during overcurrent events to reduce duty cycle and limit power dissipation.

Protection architecture includes pulse-by-pulse current limiting (3.75–5.25 A min/max), thermal shutdown at 150 °C ±10 °C, feedback disconnection detection, and inhibit logic enabling zero-load quiescent current (50–100 µA). The device uses an internal 3.3 V reference (±2% accuracy) and supports external resistive feedback for precise output programming.

Key Specifications

Pinout & Package

Package: HSOP8 with exposed thermal pad (mechanical data per ST DocID018760 Rev 3, Table 10). Exposed pad must be soldered to PCB ground plane for thermal performance (R_THJ-A ≈ 40 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM5164QPWPRQ1 and TPS54332DR, the A5975DTR uniquely combines AEC-Q100 qualification, 4 V cold-crank support, integrated 3 A switch, and synchronization-making it the only drop-in solution for safety-critical automotive buck stages requiring full-feature integration and regulatory compliance.

Availability

A5975DTR is available at Aetrix Electronics and suitable for engine control units, ADAS camera modules, body control modules, and infotainment systems requiring stable component supply across automotive production lifecycles.

Supply support for A5975DTR 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 microcontrollers, power ICs, sensors, and automotive-grade analog devices.

The A5975DTR belongs to ST's automotive power management portfolio, engineered specifically for robust, high-reliability DC-DC conversion in harsh vehicle environments-including extended temperature operation, EMC resilience, and functional safety alignment.

FAQ

What is the minimum input voltage required for A5975DTR to regulate under load?

The A5975DTR maintains regulation down to 4 V input across its full 3 A output range, verified per datasheet Section 3 (Electrical Characteristics) and explicitly designed for automotive cold-crank conditions. Below 4 V, the internal UVLO circuit disables switching to protect the device; no regulation is guaranteed at 3.9 V or lower.

Can A5975DTR operate without an external feedback resistor divider?

Yes - connecting the FB pin directly to OUT yields a fixed 1.235 V output (typ), as specified in Table 4. This configuration is valid for low-voltage applications like powering certain microcontroller cores, but requires verification of load regulation and thermal performance at full current.

How does the SYNCH pin function in master vs. slave mode?

When multiple A5975DTRs share a common SYNCH net, the device with highest natural switching frequency (212–280 kHz) becomes master and drives the net; others act as slaves, synchronizing their internal oscillators to that frequency. No external components or configuration bits are needed - behavior is automatic and hardware-defined.

Is the exposed pad on the HSOP8 package electrically connected internally?

No - the exposed pad is thermally connected only and must be soldered to a PCB ground plane for heat dissipation. It is not tied to any internal signal or power rail; ST's mechanical drawing (Table 10, DocID018760 Rev 3) confirms it is isolated and intended solely for thermal conduction.