Infineon Technologies IRF7809

Overview

IRF7809 from International Rectifier is an N-channel HEXFET® Power MOSFET designed as a synchronous rectifier (Sync FET) in high-efficiency CPU core DC-DC converters. It features 30 V V_DS, 7.5 mΩ R_DS(on) at V_GS = 4.5 V, 77.5 nC total gate charge, 3.5 W power dissipation at T_A = 25°C, and SO-8 package with CopperStrap™ interconnect for low thermal resistance.

For engineers reviewing the IRF7809 datasheet, IRF7809 pinout, IRF7809 application in multiphase VRMs, or IRF7809 equivalent for high-current synchronous buck stages, this device delivers verified conduction and switching loss trade-offs critical for mobile processor power delivery under tight thermal constraints.

Technical Context

The IRF7809 operates as a low-side synchronous rectifier in multiphase buck converters, where its 7.5 mΩ on-resistance minimizes I²R losses during high-current conduction (up to 17.6 A continuous), and its 77.5 nC gate charge enables efficient drive with standard PWM controllers. Its Q_sw of 23.9 nC and Q_oss of 30 nC support fast switching transitions while limiting shoot-through risk and capacitive energy loss.

Thermally, the SO-8 package uses CopperStrap™ interconnect to achieve R_θJL = 20°C/W and R_θJA = 35°C/W (on 1-in² copper board), enabling sustained operation at T_J ≤ 150°C under 16.3 A load at T_L = 90°C - a key requirement for compact VRM layouts near CPU die.

Key Specifications

Pinout & Package

IRF7809 is housed in a standard SO-8 surface-mount package with exposed drain paddle (thermally enhanced). The package uses CopperStrap™ interconnect technology to reduce both electrical resistance and junction-to-lead thermal resistance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IRF7832 and SiR872DP, the IRF7809 offers the best balance of gate drive compatibility (77.5 nC), thermal robustness (R_θJL = 20°C/W), and proven VRM qualification history - making it the default choice for cost-sensitive, high-volume notebook and embedded computing platforms.

Availability

IRF7809 is available at Aetrix Electronics and suitable for mobile CPU VRMs, server memory regulators, GPU power stages, and industrial FPGA core supplies requiring stable component supply and long-lifecycle support.

Supply support for IRF7809 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

International Rectifier (now part of Infineon Technologies since 2015) was a pioneer in power MOSFET design, specializing in high-efficiency switching devices for computing and industrial power conversion.

The IRF7809 belongs to the HEXFET® chipset family developed specifically for CPU/GPU core voltage regulation, emphasizing low R_DS(on), controlled Q_G, and thermally optimized packaging for multiphase DC-DC applications.

FAQ

Is IRF7809 rated for 100% R_DS(on) testing?

Yes. Per the official datasheet (PD-93812), every IRF7809 unit undergoes 100% R_DS(on) screening at V_GS = 4.5 V and ID = 15 A. This ensures guaranteed maximum on-resistance across all production lots, critical for current-sharing accuracy in multi-phase VRMs without binning.

What is the maximum recommended gate drive voltage for IRF7809?

The absolute maximum gate-source voltage is ±12 V. For reliable operation, gate drive should be limited to 4.5–10 V. Driving above 10 V yields diminishing R_DS(on) improvement (<0.5 mΩ reduction from 4.5 V to 10 V) while increasing gate oxide stress and ESD vulnerability in high-noise VRM environments.

Can IRF7809 be used as a high-side switch in a buck converter?

No. IRF7809 is optimized as a low-side synchronous rectifier. Its gate threshold voltage (1.0 V typ) and lack of integrated level-shifting circuitry make it unsuitable for high-side operation without external bootstrap or isolated gate drive - unlike dedicated high-side controllers or floating-gate MOSFET drivers.

Does IRF7809 require a Schottky parallel diode for reverse recovery mitigation?

No. While the datasheet notes Q_rr reduction when paired with a 10BQ040 Schottky (Q_rr(s) = 87 nC), the IRF7809's body diode is fully characterized and usable in standard synchronous buck topologies. Parallel Schottky diodes are optional and only beneficial in ultra-high-di/dt (>1 kA/µs) or zero-voltage-switching designs.