Infineon Technologies IRFU3709ZPBF

Overview

IRFU3709ZPBF from Infineon Technologies is a 30V, 86A N-channel enhancement-mode HEXFET Power MOSFET in I-Pak package, featuring 5.2 mΩ R_DS(on) at V_GS = 10 V, 17 nC total gate charge, and 1.9 °C/W junction-to-case thermal resistance. It serves as a high-efficiency synchronous rectifier or control FET in high-frequency DC-DC converters for server CPU power delivery.

For engineers reviewing the IRFU3709ZPBF datasheet, IRFU3709ZPBF pinout, IRFU3709ZPBF application, or IRFU3709ZPBF equivalent, key selection criteria include low R_DS(on) at 4.5 V (6.5 mΩ max), ultra-low gate impedance, fully characterized avalanche capability (E_AS = 450 mJ), and robust body diode performance (Q_rr = 25–37 nC, t_rr = 29–44 ns).

Technical Context

This MOSFET employs planar silicon HEXFET architecture optimized for fast switching in hard-switched and synchronous buck topologies. Its gate threshold voltage (1.35–2.25 V) enables reliable 4.5 V logic-level drive, while low Q_gd/Q_gs1 ratio minimizes C_dv/dt turn-on risk in high-dV/dt node applications.

Thermal design is supported by validated R_θJC = 1.9 °C/W and R_θJA = 50 °C/W (PCB mount). Avalanche ruggedness is specified under clamped inductive load conditions (I_AR = 12 A, E_AS = 450 mJ at T_J = 25°C), confirming suitability for non-isolated converter primary-side switching with transient overvoltage tolerance.

Key Specifications

Pinout & Package

IRFU3709ZPBF uses the industry-standard I-Pak (TO-251AA) surface-mount package with three terminals: Drain (D), Source (S), and Gate (G). The drain tab is electrically connected to the drain terminal and thermally coupled to the PCB copper for enhanced heat transfer.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel power MOSFET applications.

Compared with IRLR3709ZPBF and STP36NF06L, IRFU3709ZPBF delivers superior thermal performance (1.9 °C/W R_θJC) and lowest R_DS(on) in its voltage class, making it optimal for high-current, high-efficiency synchronous rectification where junction temperature control is critical.

Availability

IRFU3709ZPBF is available at Aetrix Electronics and suitable for server VRM power stages, telecom DC-DC converters, and industrial motor drive inverters requiring stable component supply across extended production lifecycles.

Supply support for IRFU3709ZPBF 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 manufacturer specializing in power management, automotive electronics, and industrial control ICs, with global manufacturing and quality certification to ISO/TS 16949 and IATF 16949.

The HEXFET Power MOSFET product line targets high-efficiency power conversion in computing, telecom, and industrial applications, emphasizing low R_DS(on), fast switching, and rugged avalanche performance for hard-switched topologies.

FAQ

What is the maximum continuous drain current at 100°C case temperature?

The IRFU3709ZPBF supports 61 A continuous drain current at T_C = 100°C, as specified in the Absolute Maximum Ratings table. This value reflects thermal derating from the 86 A rating at 25°C, based on linear derating factor of 0.53 W/°C and R_θJC = 1.9 °C/W. Operation above this current requires active cooling or reduced ambient temperature.

Does IRFU3709ZPBF require a gate driver with negative turn-off capability?

No. The device's gate threshold voltage (1.35–2.25 V) and low gate charge (17 nC) allow reliable switching with standard 0–12 V gate drivers. Negative turn-off is unnecessary because the MOSFET has no inherent shoot-through risk in typical buck configurations and exhibits stable V_GS(th) drift (−5.6 mV/°C) that prevents thermal runaway.

Can IRFU3709ZPBF be used in parallel configurations?

Yes - its positive R_DS(on) temperature coefficient (normalized R_DS(on) increases with junction temperature, per Fig 4) ensures inherent current sharing when paralleled. For stable operation, match gate drive loop inductance and use individual 1–2 Ω gate resistors to suppress oscillation; layout symmetry is critical to minimize current imbalance.

Is the body diode suitable for reverse recovery in synchronous rectification?

Yes - the body diode is fully characterized with t_rr = 29–44 ns and Q_rr = 25–37 nC at I_F = 12 A, V_DD = 15 V, and di/dt = 100 A/µs. These values enable clean commutation in 500 kHz–1 MHz synchronous buck converters, provided gate timing accounts for reverse recovery delay to avoid cross-conduction.