Infineon Technologies IRLU7821

Overview

IRLU7821 from Infineon Technologies is a 30V N-channel D-Pak power MOSFET optimized for high-frequency synchronous rectification in isolated DC-DC converters and low-voltage buck regulators. It delivers 10 mΩ R_DS(on) at V_GS = 4.5 V, 10 nC total gate charge, and 65 A continuous drain current at T_C = 25°C, enabling efficient power conversion in telecom and industrial power supplies.

For engineers reviewing the IRLU7821 datasheet, IRLU7821 pinout, IRLU7821 application, or IRLU7821 equivalent, key selection criteria include its ultra-low gate impedance, fully characterized avalanche capability (230 mJ), body diode reverse recovery charge (15–23 nC), and thermal resistance (R_θJC = 2.0°C/W) for thermally constrained PCB layouts.

Technical Context

The IRLU7821 employs a trench-gated HEXFET structure with optimized channel geometry to achieve low on-resistance at logic-level gate drive (4.5 V). Its gate charge profile-Q_gs1 = 2.0 nC, Q_gd = 2.5 nC, Q_sw = 3.7 nC-supports fast switching with minimal C_dv/dt turn-on risk in synchronous FET positions.

It features a fully rated intrinsic body diode (V_SD ≤ 1.0 V, t_rr = 26–38 ns, Q_rr = 15–23 nC) and is characterized for unclamped inductive switching up to 230 mJ single-pulse avalanche energy, making it suitable for hard-switched topologies where voltage transients occur.

Key Specifications

Pinout & Package

IRLU7821 uses the industry-standard D-Pak (TO-252AA) surface-mount package with exposed drain pad for thermal and electrical performance. The three-terminal configuration supports high-current PCB routing and low-inductance source connections.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IRLR7821 and SiR872DP, the IRLU7821 offers the best balance of low gate charge (10 nC), robust avalanche rating (230 mJ), and D-Pak thermal performance (R_θJC = 2.0°C/W), making it optimal for production-grade telecom and industrial SMPS where layout density and transient resilience are prioritized.

Availability

IRLU7821 is available at Aetrix Electronics and suitable for telecom DC-DC converters, server voltage regulators, and industrial motor drives requiring stable component supply and long-term manufacturing continuity.

Supply support for IRLU7821 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, and industrial control ICs and discrete devices, with global manufacturing and quality certification to ISO/TS 16949 and IECQ QC 080000.

The IRLU7821 belongs to Infineon's HEXFET® logic-level power MOSFET product line, engineered specifically for high-efficiency, high-frequency DC-DC conversion in space- and thermally constrained applications.

FAQ

What is the maximum continuous drain current for IRLU7821 at 100°C case temperature?

The IRLU7821 supports 47 A continuous drain current at T_C = 100°C with V_GS = 10 V, as specified in the Absolute Maximum Ratings table. This reflects thermal derating from 65 A at 25°C due to junction-to-case thermal resistance (2.0°C/W) and power dissipation limits at elevated temperatures.

Does IRLU7821 require a gate resistor for stable switching in a 500 kHz synchronous buck converter?

Yes-a gate resistor (typically 2.2–10 Ω) is recommended to dampen gate-source ringing caused by PCB trace inductance and the MOSFET's 1030 pF input capacitance. Without it, parasitic oscillation can cause partial turn-on, increased switching loss, and potential gate oxide stress under high dV/dt conditions.

Can IRLU7821 replace a Schottky diode in a 12 V output synchronous rectifier without additional circuit changes?

Yes, but only with proper gate drive: the MOSFET requires active control synchronized to the primary-side switch, typically via a dedicated synchronous rectifier controller or transformer-coupled gate drive. Unlike a passive diode, it cannot self-commutate and will fail short-circuit if driven with incorrect timing or insufficient gate voltage.

Is the body diode of IRLU7821 suitable for reverse polarity protection in a 24 V automotive accessory circuit?

No-the body diode conducts from source to drain, so it does not block reverse voltage applied to the drain. For reverse polarity protection, the device must be placed with source toward the load and drain toward the supply, and even then, its 1.0 V forward drop and limited surge rating (260 A pulsed) make discrete TVS or dedicated protection ICs more appropriate for automotive environments.