Vishay Siliconix IRFSL31N20DTRR

Overview

IRFSL31N20DTRR from Infineon Technologies is a 200 V, 31 A, 0.082 Ω D2PAK-3L N-channel enhancement-mode power MOSFET optimized for high-frequency DC-DC converters in telecom 48 V input forward topologies. It features fully characterized avalanche capability (420 mJ single-pulse), low gate-to-drain charge (33–49 nC), and effective output capacitance of 170 pF for simplified snubberless design.

For engineers reviewing the IRFSL31N20DTRR datasheet, IRFSL31N20DTRR pinout, IRFSL31N20DTRR application, or IRFSL31N20DTRR equivalent, key selection criteria include its 200 V V_BRDSS rating, 0.082 Ω R_DS(on) at 10 V, 70–110 nC total gate charge, 124 A pulsed drain current, and D2PAK thermal performance with 0.75 °C/W R_θJC.

Technical Context

This MOSFET employs HEXFET® silicon technology with planar-gate vertical DMOS architecture, enabling robust unclamped inductive switching (UIS) and fast diode recovery (t_rr = 200–300 ns). Its gate threshold voltage (3.0–5.5 V) ensures reliable turn-on with standard 10 V drivers while maintaining noise immunity.

The device integrates a co-packaged body diode with V_SD = 1.3 V at 18 A and controlled reverse recovery charge (Q_rr = 1.7–2.6 µC), supporting synchronous rectification and ZVS operation in resonant topologies. Dynamic parameters-including C_iss = 2370 pF, C_oss = 150–2860 pF (voltage-dependent), and Crss = 78 pF-are fully characterized per AN-1001 to support accurate loss modeling.

Key Specifications

Pinout & Package

D2PAK (TO-263-3L) surface-mount package with exposed drain pad for enhanced thermal transfer. Standard JEDEC MO-211AC outline; lead-free and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STP20NM20 and IXTP30N20P, IRFSL31N20DTRR delivers superior current capability (31 A vs. 20/30 A), lower R_DS(on) (0.082 Ω), and verified 420 mJ avalanche energy-making it the only option qualified for high-reliability telecom forward converters requiring intrinsic UIS robustness and D2PAK thermal performance.

Availability

IRFSL31N20DTRR is available at Aetrix Electronics and suitable for telecom power supplies, industrial DC-DC modules, server VRMs, and motor drive inverters requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for IRFSL31N20DTRR 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, automotive, and industrial control ICs and discrete devices, with global manufacturing and R&D centers.

The IRFSL31N20DTRR belongs to Infineon's HEXFET® Power MOSFET product line, engineered specifically for high-efficiency, high-frequency switched-mode power supplies in telecom, computing, and industrial infrastructure.

FAQ

What is the maximum junction temperature rating for IRFSL31N20DTRR?

The IRFSL31N20DTRR has a maximum operating junction temperature of +175 °C, as specified in its Absolute Maximum Ratings table. This allows reliable operation in high-ambient environments such as enclosed telecom rectifiers or industrial motor drives. The device's R_θJC = 0.75 °C/W enables efficient heat transfer to the PCB or heatsink, and its normalized R_DS(on) curve shows less than 2× increase from 25 °C to 175 °C-ensuring predictable conduction loss across the full thermal range. Always verify actual T_J using measured case temperature and power dissipation in the final layout.

Does IRFSL31N20DTRR support gate drive with 5 V logic levels?

No, IRFSL31N20DTRR is not a logic-level MOSFET; its gate threshold voltage (V_GS(th)) ranges from 3.0 V to 5.5 V, and full enhancement requires V_GS ≥ 10 V to achieve the specified 0.082 Ω R_DS(on). Driving IRFSL31N20DTRR with only 5 V risks incomplete turn-on, elevated conduction loss, and thermal runaway under load. The datasheet confirms R_DS(on) is guaranteed only at V_GS = 10 V, and transfer characteristics show significant current roll-off below 7 V. Use a dedicated 10–15 V gate driver stage-not 3.3 V or 5 V microcontroller outputs-to ensure reliable operation of IRFSL31N20DTRR.

What is the avalanche energy rating of IRFSL31N20DTRR and how is it tested?

The IRFSL31N20DTRR is rated for 420 mJ single-pulse avalanche energy (E_AS) with starting junction temperature at 25 °C, tested per the unclamped inductive switching (UIS) circuit in Figure 12a of its datasheet (L = 3.8 mH, R_G = 25 Ω, I_AS = 18 A). It also supports 20 mJ repetitive avalanche energy (E_AR). This rating validates its ability to safely absorb inductive energy during fault conditions-such as transformer saturation or controller lockup-without destructive failure. The device's fully characterized avalanche voltage and current curves (page 6) confirm robustness across temperature, making IRFSL31N20DTRR suitable for telecom forward converters where primary-side overcurrent protection must be inherently reliable.

How does the body diode performance of IRFSL31N20DTRR compare to external Schottky diodes?

The IRFSL31N20DTRR body diode has V_SD = 1.3 V at 18 A and reverse recovery charge Q_rr = 1.7–2.6 µC, which is slower and higher-drop than modern 45 V Schottky diodes (e.g., ~0.5 V, <0.2 µC). However, its integrated structure eliminates PCB parasitics and reduces component count in synchronous rectifier designs. In medium-frequency (200–500 kHz) telecom forward converters, the IRFSL31N20DTRR body diode's t_rr = 200–300 ns and controlled Q_rr allow acceptable recovery loss-especially when paired with optimized gate timing-whereas discrete Schottkys introduce layout-sensitive ringing. For best results, use IRFSL31N20DTRR's body diode only where integration benefit outweighs efficiency penalty; otherwise, pair IRFSL31N20DTRR with an external Schottky for freewheeling paths.

Is IRFSL31N20DTRR pin-compatible with IRFS31N20D or IRFB31N20D?

No, IRFSL31N20DTRR is not pin-compatible with IRFS31N20D (TO-220AB) or IRFB31N20D (TO-262). Although all three share identical electrical specifications and belong to the same product family, they differ in package type and pin assignment: IRFSL31N20DTRR uses D2PAK-3L (surface-mount, leads 1–3 = G-D-S), IRFS31N20D uses TO-220AB (through-hole, leads 1–3 = G-D-S), and IRFB31N20D uses TO-262 (single-inline, leads 1–3 = G-D-S but with different mechanical footprint and thermal pad configuration). PCB layout, thermal relief, and soldering process must be redesigned for each package. IRFSL31N20DTRR's D2PAK offers superior thermal performance (R_θJC = 0.75 °C/W) versus TO-220AB (R_θJC = 1.3 °C/W), but requires requalification of assembly and reliability testing.