Vishay Siliconix IRF820A

Overview

IRF820A from Vishay Siliconix is a 500 V, 2.5 A N-channel power MOSFET in TO-220AB package, optimized for high-voltage switching in SMPS topologies including two-transistor forward and full-bridge converters. It delivers R_DS(on) = 3.0 Ω at V_GS = 10 V, Q_g = 17 nC, and 140 mJ single-pulse avalanche energy - enabling robust unclamped inductive switching in industrial power supplies.

For engineers reviewing the IRF820A datasheet, IRF820A pinout, IRF820A application, or IRF820A equivalent, key selection criteria include its 500 V V_DS, 2.5 A continuous drain current at T_C = 25 °C, 3.4 V/ns peak diode recovery dV/dt rating, and TO-220AB thermal performance with R_thJC = 2.5 °C/W - critical for thermal design in compact, convection-cooled SMPS.

Technical Context

The IRF820A employs planar vertical DMOS technology with fully characterized C_iss (340 pF), C_oss (53 pF), and C_rss (2.7 pF) to support predictable snubberless hard-switching. Its gate threshold voltage range (2.0–4.5 V) ensures reliable turn-on with standard 10 V gate drivers while maintaining noise immunity.

Avalanche ruggedness is validated per JEDEC JESD24-1: E_AS = 140 mJ (single pulse), I_AR = 2.5 A (repetitive), and dV/dt = 3.4 V/ns - confirming suitability for unclamped inductive loads without external clamping. Body diode parameters (t_rr = 330–500 ns, Q_rr = 760–1140 nC) are specified at I_F = 2.5 A, dI/dt = 100 A/μs, defining reverse recovery behavior in synchronous rectification or freewheeling roles.

Key Specifications

Pinout & Package

IRF820A is housed in a through-hole TO-220AB package with isolated tab (drain-connected), rated for 50 W maximum power dissipation at T_C = 25 °C and R_thJC = 2.5 °C/W. Mounting requires 1.1 N·m torque on M3 screw.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP5NB50FP and FQP5N50C, the IRF820A provides lower gate charge (17 nC vs. ≥20 nC) and verified avalanche energy (140 mJ), making it preferable for space-constrained, gate-drive-limited SMPS where reliability under transient overload is critical - despite its higher R_DS(on).

Availability

IRF820A is available at Aetrix Electronics and suitable for switch mode power supplies, uninterruptible power supplies, and high-speed power switching applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for IRF820A 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

Vishay Siliconix is a global leader in discrete semiconductors, specializing in high-reliability MOSFETs, diodes, and optoelectronics for industrial, automotive, and computing markets.

The IRF820A belongs to Vishay's legacy high-voltage power MOSFET product line, engineered for ruggedness and predictability in offline AC/DC conversion, emphasizing avalanche survivability and gate drive simplicity over ultra-low R_DS(on).

FAQ

What is the maximum continuous drain current for the IRF820A at 100 °C case temperature?

The IRF820A supports 1.6 A continuous drain current at T_C = 100 °C, as defined by its linear derating factor of 0.40 W/°C from the 50 W maximum power dissipation at T_C = 25 °C. This value is critical for thermal design in enclosed or convection-limited environments where heatsink performance is constrained. The IRF820A must be operated within this limit to avoid exceeding T_J = 150 °C.

Does the IRF820A have a fully isolated drain tab in the TO-220AB package?

Yes, the IRF820A uses the TO-220AB package variant with an electrically isolated drain tab, allowing direct mounting to a heatsink without additional insulation hardware. This isolation is confirmed in Vishay's ordering information and mechanical drawings for IRF820APbF-BE3. The IRF820A's R_thCS = 0.50 °C/W assumes direct metal-to-metal contact between the isolated tab and heatsink surface.

What is the gate-source threshold voltage range for the IRF820A, and how does it affect drive compatibility?

The IRF820A has a V_GS(th) range of 2.0 V to 4.5 V at I_D = 250 μA, confirming compatibility with standard 10 V gate drivers while providing margin against noise-induced turn-on. This threshold range ensures full enhancement at V_GS = 10 V (where R_DS(on) is specified), and the IRF820A remains functional even with moderate gate drive droop or PCB trace resistance.

Is the IRF820A suitable for use in zero-voltage switching (ZVS) circuits?

Yes, the IRF820A supports ZVS operation due to its well-characterized C_oss = 53 pF and C_{oss eff.} = 28 pF, which enable predictable resonant tank behavior. Its Q_gd/Q_g ratio of 50% enhances Miller immunity during transition, and the IRF820A's 12 ns rise time facilitates clean turn-on in phase-shifted full-bridge topologies where ZVS is implemented.

What is the body diode reverse recovery charge (Q_rr) specification for the IRF820A, and why does it matter?

The IRF820A specifies Q_rr = 760–1140 nC at T_J = 25 °C, I_F = 2.5 A, and dI/dt = 100 A/μs. This parameter directly impacts switching losses and EMI in bridge configurations: higher Q_rr increases turn-on losses in the complementary switch and raises peak current stress. Designers use this value to size dead time and select snubbers - a key consideration when deploying the IRF820A in half-bridge or full-bridge SMPS.