Infineon Technologies IRFR3709Z

Overview

IRFR3709Z from Infineon Technologies (formerly International Rectifier) is a 30V N-channel enhancement-mode HEXFET Power MOSFET in D-Pak package, optimized for high-frequency synchronous buck converters and isolated DC-DC applications. It delivers 6.5 mΩ R_DS(on) at V_GS = 10 V, 17 nC total gate charge, 300 A pulsed drain current, and 340 A body diode pulsed source current - enabling efficient power conversion in server CPU VRMs and telecom rectifiers.

For engineers reviewing the IRFR3709Z datasheet, IRFR3709Z pinout, IRFR3709Z application, or IRFR3709Z equivalent, key selection criteria include its ultra-low gate impedance, fully characterized avalanche capability (E_AS = 450 mJ), 1.9 °C/W junction-to-case thermal resistance, and validated performance at 175 °C junction temperature in hard-switched topologies.

Technical Context

This MOSFET employs planar silicon process with integrated body diode and optimized charge distribution to minimize Q_gd/Q_gs1 ratio (≈1.2:1), reducing C_dv/dt turn-on risk in synchronous FET positions. Its gate threshold voltage (1.35–2.25 V) and negative tempco (−5.6 mV/°C) support stable operation across −55 °C to +175 °C ambient.

The device is characterized for clamped inductive switching, with 29–44 ns reverse recovery time (t_rr) and 25–37 nC reverse recovery charge (Q_rr) at I_F = 12 A, V_DD = 15 V, di/dt = 100 A/µs - critical for minimizing shoot-through loss in high-side control FET / low-side synchronous rectifier configurations.

Key Specifications

Pinout & Package

IRFR3709Z uses the industry-standard D-Pak (TO-252) surface-mount package: single-row 3-pin configuration with exposed drain pad for thermal and electrical connection. Pin assignment is standardized per JEDEC MO-238.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IRFR3709Z, IRLL3709PbF offers identical electrical specs but inferior thermal performance in SMT applications, while STL30DN6LF7AG trades avalanche ruggedness for automotive qualification - making IRFR3709Z optimal for industrial/compute power where reliability under unclamped stress is non-negotiable.

Availability

IRFR3709Z is available at Aetrix Electronics and suitable for server CPU VRMs, telecom DC-DC converters, and industrial PLC power supplies requiring stable component supply and long-term lifecycle assurance.

Supply support for IRFR3709Z 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, sensor, and automotive ICs, with global manufacturing and quality certification to ISO 9001 and IATF 16949.

The HEXFET Power MOSFET product line was originally developed by International Rectifier and acquired by Infineon in 2015; it targets high-efficiency, high-reliability power conversion in computing, telecom, and industrial infrastructure.

FAQ

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

The IRFR3709Z supports 61 A continuous drain current at T_C = 100 °C, as specified in the Absolute Maximum Ratings table. This value reflects thermal derating due to reduced heat transfer at elevated case temperatures and assumes proper PCB copper area (≥1 in²) and airflow. Operation above this current requires active cooling or parallel FETs.

Does IRFR3709Z have avalanche capability, and is it tested per JEDEC JESD24-1?

Yes - IRFR3709Z is fully characterized for single-pulse avalanche with E_AS = 450 mJ at T_J = 25 °C and I_AS = 12 A, verified using the unclamped inductive test circuit per JEDEC JESD24-1. The datasheet provides E_AS vs. starting T_J curves (Fig. 12c), confirming rated performance down to 150 °C initial junction temperature.

Can IRFR3709Z be driven directly from a 3.3 V microcontroller GPIO?

No - the gate threshold voltage range is 1.35–2.25 V, but full enhancement (to achieve 6.5 mΩ R_DS(on)) requires ≥10 V V_GS. At 3.3 V, R_DS(on) exceeds 25 mΩ, increasing conduction loss by >300%. A dedicated gate driver (e.g., IR2110, MIC4422) or level-shifter is required for reliable switching in power applications.

How does the body diode's reverse recovery behavior affect synchronous rectifier performance?

The body diode exhibits t_rr = 29–44 ns and Q_rr = 25–37 nC at I_F = 12 A, which directly contributes to switching loss and shoot-through risk during dead-time transitions. In synchronous rectifier use, low Q_rr reduces energy dissipated in the high-side FET and enables shorter dead times - improving light-load efficiency by up to 2.1% in 500 kHz buck converters.