Infineon Technologies IR3476MTR1PBF

Overview

IR3476MTR1PBF from Infineon Technologies is a fully integrated 12A synchronous buck regulator with on-die high- and low-side MOSFETs, constant-on-time control, 0.5V ±1% reference, and programmable switching frequency up to 750 kHz. It operates from 3V–27V input, delivers 0.5V–12V output, and features power good output, thermal shutdown, and pre-bias startup - used in notebook CPU core power delivery.

For engineers reviewing the IR3476MTR1PBF datasheet, IR3476MTR1PBF pinout, IR3476MTR1PBF application, or IR3476MTR1PBF equivalent, key selection criteria include its integrated 20 mΩ/10 mΩ MOSFETs, FCCM mode control, thermally compensated overcurrent protection, soft-start programmability via external capacitor, and 5 mm × 6 mm QFN package with exposed thermal pad.

Technical Context

The IR3476 implements a constant-on-time (COT) hysteretic control architecture with feed-forward voltage sensing via the FF pin, enabling fast transient response without loop compensation. Its internal gate drivers support bootstrapped high-side drive and integrate deadtime control (5–30 ns) to prevent shoot-through.

Protection functions are tightly coupled to physical sensing: ISET pin current (17–21 µA) sets overcurrent threshold based on PHASE node voltage drop; VFB monitoring enables precise 0.37–0.43 V UVLO and 0.586–0.655 V OVLO with 7.5 mV hysteresis; thermal shutdown triggers at 125–140 °C with 20 °C hysteresis.

Key Specifications

Pinout & Package

IR3476MTR1PBF is housed in a thermally enhanced 5 mm × 6 mm QFN package with 28-pin layout and exposed thermal pad (EP) on underside for PCB-level heat dissipation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck regulator applications.

Compared with MP8765GQ-Z and TPS546D24RQF, IR3476MTR1PBF uniquely balances 12 A capability, analog simplicity (no compensation, no firmware), and robust protection (pre-bias, thermal OCP, FCCM control) in a single 5×6 mm package - ideal for high-reliability embedded power where digital interfaces add unnecessary risk.

Availability

IR3476MTR1PBF is available at Aetrix Electronics and suitable for notebook CPU core power, graphics card VRMs, and 12 V distributed power systems requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for IR3476MTR1PBF 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

Infineon Technologies is a German semiconductor leader specializing in power management, automotive MCUs, and industrial gate drivers, with global manufacturing and AEC-Q100 qualification capabilities.

The SupIRBuck™ product line delivers highly integrated DC/DC regulators targeting space-constrained, high-current POL applications in computing and consumer electronics - emphasizing ease-of-use, thermal robustness, and analog reliability over digital complexity.

FAQ

What is the minimum recommended output capacitance for stable operation?

The IR3476MTR1PBF requires ≥68 µF low-ESR output capacitance, as validated in the demo board (C3 = 68 µF polymer). Using less than 47 µF risks instability under heavy load transients due to insufficient phase margin in the COT loop. Ceramic + polymer hybrid banks are preferred to balance ESR and ripple current handling.

Can the IR3476MTR1PBF operate with an input voltage below 3 V?

No - the absolute minimum operating VIN is 3 V per the Recommended Operating Conditions table. Below 3 V, the internal gate drivers cannot sustain sufficient VGS for the high-side MOSFET, causing dropout and unregulated output. The 0.3 V absolute maximum rating applies only to non-operational stress conditions, not functional use.

How is the switching frequency set, and what resistor value yields 300 kHz?

Switching frequency is set by a resistor from the FF pin to VIN. For 300 kHz at VIN = 12 V, a 180 kΩ resistor is specified in the Electrical Characteristics table. The on-time is inversely proportional to VIN, so frequency remains stable across input variation - critical for EMI compliance in variable-input systems.

Is the PHASE pin electrically isolated from other pins, and what is its voltage rating?

The PHASE pin is not isolated - it connects directly to the drain of the high-side MOSFET and source of the low-side MOSFET. Its absolute maximum rating is –5 V (100 ns) negative swing and +30 V DC, per the Absolute Maximum Ratings table. Layout must minimize parasitic inductance to avoid overshoot exceeding these limits during switching transitions.