Vishay Siliconix IRFBF20

Overview

IRFBF20 from Vishay Siliconix is a 900 V, 1.7 A N-channel power MOSFET in TO-220AB package, featuring 8.0 Ω R_DS(on) at V_GS = 10 V, 38 nC total gate charge, and repetitive avalanche rating up to 1.7 A - designed for high-voltage flyback and snubberless AC-DC power supplies.

For engineers reviewing the IRFBF20 datasheet, IRFBF20 pinout, IRFBF20 application, or IRFBF20 equivalent, key selection criteria include its 900 V V_DS, low 4.7 nC Q_gs, fast 21 ns rise time, robust 180 mJ single-pulse avalanche energy, and TO-220AB thermal performance with R_thJC = 2.3 °C/W.

Technical Context

This N-channel enhancement-mode MOSFET uses planar silicon technology optimized for high-voltage switching with dynamic dV/dt immunity (1.5 V/ns) and intrinsic body diode recovery (t_rr = 350–530 ns). Its gate threshold voltage (2.0–4.0 V) ensures stable turn-on under wide temperature ranges (-55 to +150 °C).

The device supports unclamped inductive switching with validated 1.7 A repetitive avalanche current and 5.4 mJ energy, enabling rugged operation in offline SMPS without external clamping. Internal source/drain inductances (L_S = 7.5 nH, L_D = 4.5 nH) are characterized for accurate switching waveform modeling.

Key Specifications

Pinout & Package

IRFBF20 is housed in a through-hole TO-220AB package with isolated tab (drain-connected), standard 2.54 mm lead pitch, and 2.3 °C/W junction-to-case thermal resistance. Mounting torque: 1.1 N·m (10 lbf·in) for M3 screw.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP9NK90ZFP and IXTH1R1N90P, the IRFBF20 offers balanced trade-offs: moderate R_DS(on) and Q_g for cost-sensitive 1–2 A flyback designs, TO-220AB compatibility with legacy layouts, and proven avalanche ruggedness without ZVS complexity or TO-247 footprint overhead.

Availability

IRFBF20 is available at Aetrix Electronics and suitable for industrial AC-DC adapters, LED driver power stages, and snubberless flyback converters requiring stable component supply and long-term manufacturing continuity.

Supply support for IRFBF20 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 power MOSFETs, diodes, and optoelectronics with emphasis on reliability, ruggedness, and application-specific optimization.

The IRFBF20 belongs to Vishay's third-generation high-voltage power MOSFET family, engineered for cost-effective, thermally efficient switching in offline power conversion where avalanche robustness and dV/dt immunity are critical.

FAQ

What is the maximum continuous drain current for IRFBF20 at 100 °C case temperature?

The IRFBF20 supports 1.1 A continuous drain current at T_C = 100 °C, derated linearly from 1.7 A at 25 °C using the 0.43 W/°C derating factor. This value reflects thermal limits of the TO-220AB package and ensures safe operation in enclosed industrial enclosures where heatsink temperature rises above ambient. The IRFBF20 datasheet confirms this rating in the Absolute Maximum Ratings table under "Continuous drain current".

Does IRFBF20 have a fully rated body diode for freewheeling applications?

Yes, the IRFBF20 integrates a robust body diode rated for 1.7 A continuous source-drain current and 6.8 A pulsed current, with t_rr = 350–530 ns and Q_rr = 0.85–1.3 nC. These parameters are measured under standardized conditions (T_J = 25 °C, I_F = 1.7 A, dI/dt = 100 A/μs) and make the IRFBF20 suitable for DCM flyback freewheeling and synchronous rectification assist roles where diode recovery behavior directly impacts efficiency.

Can IRFBF20 be used in parallel configurations, and what design considerations apply?

Yes, the IRFBF20 is explicitly designed for ease of paralleling, supported by low gate threshold variation (2.0–4.0 V), matched transconductance, and low Q_gd/Q_gs ratio (21/4.7 ≈ 4.5). To ensure current sharing, use individual gate resistors (≥10 Ω), minimize layout asymmetry, and maintain equal thermal coupling. The IRFBF20 datasheet highlights this capability in its Features list and validates it via thermal and dynamic testing across production lots.

What is the gate-source voltage limit for IRFBF20, and why is it important?

The IRFBF20 has a ±20 V gate-source voltage limit, meaning gate drive must stay within -20 V to +20 V to avoid oxide damage. Exceeding this range risks permanent gate dielectric breakdown. This specification is critical during startup, shutdown, or fault conditions where negative spikes may occur - hence gate clamping (e.g., Zener diodes) is recommended. The IRFBF20 Absolute Maximum Ratings table explicitly defines V_GS = ±20 V as non-repetitive stress limit.

How does the IRFBF20's avalanche rating compare to standard MOSFETs without this specification?

Unlike standard MOSFETs, the IRFBF20 is fully tested and rated for repetitive avalanche (I_AR = 1.7 A, E_AR = 5.4 mJ) and single-pulse avalanche (E_AS = 180 mJ), verified per JEDEC JESD24-11. This means the IRFBF20 can repeatedly absorb inductive energy without degradation - essential in snubberless flyback designs where transformer leakage inductance dumps energy into the switch. Standard MOSFETs lack this validation and may fail catastrophically under identical conditions.