STMicroelectronics A6983IQTR

Overview

A6983IQTR from STMicroelectronics is an AEC-Q100 qualified synchronous iso-buck DC-DC controller for automotive isolated power supplies, implementing peak current mode control in forced PWM operation. It supports 3.5 V to 38 V input, delivers up to 10 W isolated output via transformer coupling, regulates primary-side voltage without optocoupler (0.85 V FB reference), and features 4.5 A peak source/sink capability for tracked soft-start of secondary outputs - used in on-board chargers and IGBT/SiC gate drive supplies.

For engineers reviewing the A6983IQTR datasheet, A6983IQTR pinout, A6983IQTR application, or A6983IQTR equivalent, key selection considerations include its iso-buck topology support, -40 °C to +150 °C junction temperature rating, 200 kHz–1 MHz programmable switching frequency with optional spread spectrum, internal compensation, and QFN16 (3×3 mm) package with exposed thermal pad.

Technical Context

The A6983IQTR implements a peak current mode control architecture with fixed-frequency forced PWM operation, enabling negative current conduction during low-side switch conduction to transfer energy to the secondary winding. Its 390 ns current-sense blanking time suppresses transformer leakage-induced oscillations, and internal slope compensation prevents subharmonic instability across duty cycles.

It integrates dual MOSFET drivers (HS/LS), transconductance error amplifier with internal compensation network, programmable oscillator with synchronization input (EN/CLKIN), and pulse-by-pulse overcurrent protection on both high- and low-side switches. The device supports VBIAS switchover to improve light-load efficiency and includes thermal shutdown at 165 °C with 30 °C hysteresis.

Key Specifications

Pinout & Package

QFN16 (3 × 3 mm) package with 0.5 mm pitch and exposed thermal pad (EP) requiring connection to AGND/PGND for thermal and electrical integrity. Pin numbering follows top-through view per DS14123 Rev 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar iso-buck controller applications.

Compared with UCC28911DR and LM5180QDGSRQ1, the A6983IQTR uniquely enables true iso-buck operation with bidirectional current flow, transformer-coupled energy transfer, and primary-side regulation - making it the only option among the three capable of supporting high-power, sequenced, isolated auxiliary rails in automotive traction systems.

Availability

A6983IQTR is available at Aetrix Electronics and suitable for automotive on-board chargers, electric traction inverters, and isolated gate drive supplies requiring stable component supply across extended temperature and high-reliability production cycles.

Supply support for A6983IQTR 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 IP portfolio and vertical manufacturing capabilities.

The A6983IQTR belongs to ST's automotive-grade power conversion portfolio, designed specifically for high-efficiency, isolated DC-DC conversion in HEV/EV powertrain and ADAS systems where safety, thermal resilience, and EMI robustness are critical.

FAQ

What is the purpose of the VINLDO pin on the A6983IQTR?

The VINLDO pin supplies the internal LDO that powers analog circuitry and must be connected to the main VIN rail through an RC filter (e.g., 0.1 kΩ + 1 µF). This filtering reduces noise coupling into sensitive analog blocks like the error amplifier and current sense amplifiers, improving regulation accuracy and stability - especially critical in noisy automotive environments with high dv/dt transients.

Can the A6983IQTR operate without an external transformer?

No. The A6983IQTR is exclusively designed for iso-buck topology and requires a two-winding transformer to establish galvanic isolation and transfer energy to the secondary side. It does not function as a standard buck converter - the transformer is integral to its operation, defining the secondary output voltage ratio and enabling primary-side regulation without optocouplers or secondary-side feedback components.

How does the VBIAS switchover feature improve efficiency?

When VBIAS is connected to the regulated primary output (e.g., 12 V), the device draws quiescent current from that rail instead of VIN, reducing total input current draw at light loads. Data shows up to 5% efficiency gain on the primary output and >3% on the isolated output at 10% load - directly extending battery runtime in always-on automotive subsystems while lowering thermal stress on input capacitors and traces.

What happens during thermal shutdown, and how does recovery work?

When junction temperature reaches 165 °C (typ), the A6983IQTR disables switching, holds EN active, and maintains internal bias until temperature drops by 30 °C (hysteresis). Recovery requires either manual EN toggle or automatic restart after cooldown - no latching behavior. During shutdown, PGOOD goes low, signaling fault condition to system controllers, and soft-start reinitializes upon resumption to prevent inrush current.