IRF4905SPBF - 55V P-Channel HEXFET MOSFET, 42A D2PAK | Infineon
MPN: IRF4905SPBF ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.45 | $2.45 |
| 10 | $2.15 | $21.50 |
| 100 | $1.78 | $178.00 |
| 500 | $1.42 | $710.00 |
| 1,000 | $1.18 | $1,180.00 |
IRF4905SPBF Overview
A power MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) is the dominant switching element in modern power electronics. P-channel variants conduct when the gate is pulled below the source, making them ideal for high-side switching where a low-side N-channel would require a charge pump. The IRF4905SPBF belongs to the broader class of power MOSFETs, which sit within discrete semiconductors and, ultimately, power management ICs at the system level.
Key features include an ultra-low on-resistance of 20 mOhm maximum at VGS = -10V, a fast body-diode recovery suitable for half-bridge topologies, and a junction operating temperature ceiling of 150 C. The planar cell structure provides a wide safe operating area (SOA) for linear-mode and inductive-switching loads, while JEDEC-qualified silicon and industry-standard surface-mount D2PAK footprint enable drop-in compatibility on existing layouts. According to the manufacturer datasheet, dynamic dv/dt is ruggedized for repetitive avalanche stress.
Architecturally, the IRF4905SPBF uses a vertical HEXFET die that places the source on top and the drain on the bottom tab, allowing the PCB copper pad to double as a heatsink. The 175 C maximum junction and 0.6 C/W junction-to-case thermal resistance enable 170W power handling with proper PCB layout. Gate threshold is specified at -2.0V to -4.0V, allowing direct drive from 5V or 12V logic-level shifters.
Typical applications include high-side load switches in automotive 12V systems, battery protection and reverse-polarity protection circuits, motor-speed-control H-bridges, and synchronous-rectifier replacements for Schottky diodes in buck converters. The low RDS(on) at -10V VGS makes it ideal where conduction loss dominates.
When designing with this part, ensure the gate-drive voltage swings fully to -10V (or below) for rated RDS(on), and that PCB copper area under the drain tab meets SOA requirements at peak current. Use a gate-source resistor of 10 kOhm or higher to prevent inadvertent turn-on during fast dV/dt transients.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for IRF4905SPBF — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with IRF4905SPBF (same form factor and footprint) — differing in Package, Operating Junction Temperature, Technology, Drain-Source Voltage (VDS), RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
IRF4905STRLPBF
✅ Drop-In✓ In Stock
$0.95 / Unit
View Datasheet →IRF4905STRRPBF
✅ Drop-In✓ In Stock
$0.94 / Unit
View Datasheet →IRF4905SPBF
✅ Drop-In✓ In Stock
$1.18 / Unit
View Datasheet →NTD4905PT4G
✅ Drop-In📋 Reference alternative (not in catalog)
SUM110P06-55L
✅ Drop-In📋 Reference alternative (not in catalog)
BSZ15DC02KDHXTMA1
✅ Drop-In✓ In Stock
$0.74 / Unit
View Datasheet →IRF4905SPBF Maximum Ratings & Electrical Characteristics
| Polarity | P-Channel |
| Drain-Source Voltage (VDS) | -55 V |
| Continuous Drain Current (ID, Tc=25C) | -42 A |
| On-Resistance (RDS(on) max) | 20 mOhm @ VGS = -10V |
| Gate Threshold Voltage (VGS(th)) | -2.0 V to -4.0 V |
| Power Dissipation (PD, Tc=25C) | 170 W |
| Operating Junction Temperature | -55 C to +150 C |
| Package | D2PAK (TO-263) surface mount |
| Mounting Type | Surface Mount |
| Technology | HEXFET, planar cell |
| Total Gate Charge (Qg) | 120 nC (typical per Mouser listing) |
| RoHS Status | Compliant (PBF suffix indicates Pb-free) |
| Qualification | JEDEC standard |
IRF4905SPBF Pin Configuration
| Pin 1 | Gate — Gate drive input; connect to driver via 10 kOhm pull-up to source |
| Pin 2 | Drain — Drain terminal (also connected internally to the metal tab) |
| Pin 3 | Source — Source terminal; ground reference for P-channel operation |
Safe Operating Area (DC, Tj=150C)
Typical Applications
IRF4905SPBF is suitable for 6 applications: Automotive High-Side Load Switch, Battery Protection and Reverse-Polarity Block, H-Bridge Motor Drive (Complementary P/N Pair), Synchronous Rectifier Replacement for Schottky Diodes, Power ORing and Load-Sharing Between Supplies, Solar Charge Controller Switch.
Automotive High-Side Load Switch
The IRF4905SPBF is widely deployed as a high-side switch in 12V automotive systems where P-channel MOSFETs simplify gate drive. Its -42A continuous drain current at Tc=25C handles headlamp relays, seat heaters, and accessory loads; the 20 mOhm RDS(on) at -10V VGS keeps conduction loss under 2W at 10A. The 55V VDS rating provides 4x headroom over a 12V battery, tolerating load-dump transients up to 35V when paired with a TVS clamp. Junction temperature of -55C to +150C covers under-hood environments.
Recommended
Battery Protection and Reverse-Polarity Block
In lithium-ion battery packs and industrial battery systems, the IRF4905SPBF acts as a low-side or high-side disconnect switch. Its 42A rating covers most e-bike and power-tool packs, and the 20 mOhm RDS(on) limits voltage drop during peak discharge. The P-channel topology in high-side configuration simplifies protection logic: a simple pull-up resistor holds the gate off when the protection controller fails. The 150C junction limit allows operation in enclosed battery compartments with minimal airflow.
Recommended
H-Bridge Motor Drive (Complementary P/N Pair)
The IRF4905SPBF forms one half of a complementary H-bridge when paired with an N-channel HEXFET such as the IRF1405. Its P-channel nature eliminates the need for a high-side bootstrap or charge-pump circuit on the high-side FETs, simplifying the gate-drive section. Rated for switching below 100 kHz per the manufacturer datasheet, it handles DC and low-frequency PWM for brushed DC motors, solenoid drivers, and small BLDC applications. The 170W power dissipation rating supports sustained motor current at moderate duty cycles.
Recommended
Synchronous Rectifier Replacement for Schottky Diodes
In buck converters below 24V output, the IRF4905SPBF replaces Schottky rectifiers to reduce conduction loss and improve efficiency. At 10A output, the Schottky diode might drop 0.4V (4W loss), while the IRF4905SPBF drops I*RDS(on) = 0.2V (2W loss) - a 50% reduction. The 120nC gate charge per Mouser listing is acceptable for sub-100 kHz operation, though faster switching designs should select a part with lower Qg. The body diode's reverse recovery is also faster than most Schottky alternatives.
Recommended
Power ORing and Load-Sharing Between Supplies
The IRF4905SPBF provides efficient ORing between redundant 12V or 24V supplies, replacing Schottky diodes that dissipate tens of watts. With 20 mOhm RDS(on), a 10A ORing path drops only 0.2V and dissipates 2W instead of 8W for a Schottky. The P-channel orientation allows source-follower ORing without complex gate-drive circuitry. The 55V rating covers 24V industrial rails with headroom for transients, and the wide SOA handles the inrush surge when a supply comes online.
Recommended
Solar Charge Controller Switch
In off-grid solar systems, the IRF4905SPBF serves as a low-side disconnect switch between the solar panel array and the battery, controlled by the MPPT charge controller. Its P-channel topology simplifies high-side switching when reverse-current blocking is required, and the -42A rating covers most residential solar arrays. The 55V VDS handles open-circuit PV voltages up to 24V nominal panels with margin. The JEDEC-qualified silicon and 150C junction rating suit outdoor enclosures with temperature swings.
Recommended
Recommended Products Summary
Engineering reference data for IRF4905SPBF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | IRF4905STRLPBF | IRF4905STRRPBF | NTD4905PT4G | SUM110P06-55L | BSZ15DC02KDHXTMA1 |
|---|---|---|---|---|---|---|
| Brand | Infineon Technologies | Infineon Technologies | Infineon Technologies | onsemi | Vishay Intertechnology | Infineon Technologies |
| Package | D2PAK (TO-263) | D2PAK (TO-263) - same | D2PAK (TO-263) - same | DPAK (TO-252) - smaller | D2PAK (TO-263) - same | PG-TDSON-8 (SMD) - different |
| Drain-Source Voltage (VDS) | -55 V | -55 V | -55 V | -55 V | -55 V | -25 V |
| On-Resistance (RDS(on)) | 20 mOhm @ VGS=-10V | 20 mOhm | 20 mOhm | 28 mOhm | 11 mOhm | 15 mOhm |
| Gate Threshold Voltage (VGS(th)) | -2.0 V to -4.0 V | -2.0 V to -4.0 V | -2.0 V to -4.0 V | -1.0 V to -3.0 V (logic-level) | -2.5 V to -4.5 V | -1.0 V to -2.5 V |
| Technology | HEXFET planar | HEXFET planar | HEXFET planar | Trench MOSFET | TrenchFET | OptiMOS |
| RoHS / Pb-Free | Yes (PBF suffix) | Yes (PBF suffix) | Yes (PBF suffix) | Yes | Yes | Yes |
Key Differentiators
- Industry-standard P-channel 55V benchmark (vs NTD4905PT4G)
- Lower RDS(on) than logic-level alternatives (vs BSZ15DC02KDHXTMA1)
- Wide SOA for linear-mode operation (vs SUM110P06-55L)
Design Notes
The D2PAK tab is the primary heat-dissipation path. Estimated: with RthJC ~0.6 C/W and 1 oz copper pour of 1 square inch (RthJA ~50 C/W), the IRF4905SPBF can dissipate about 2W continuous at 25C ambient before reaching the 150C junction limit. For 10A conduction at 20 mOhm (2W loss), an additional copper pour of 4 square inches or a small heatsink is recommended. Never rely on the part's 170W PD rating without aggressive thermal management - that rating assumes infinite heatsink at Tc=25C.
Place the gate-drive resistor (typically 10-100 ohm) within 5mm of the gate pin to suppress parasitic oscillation. Keep the gate trace short and away from the drain tab to minimize Miller coupling. Add a 10 kOhm gate-source pull-down resistor to ensure the P-channel MOSFET stays off when the controller is in reset or unpowered. The drain tab copper pour should extend at least 10mm beyond the package edges for adequate heat spreading.
Do not assume the IRF4905SPBF is fully enhanced at VGS=-4.5V (logic-level). For rated 20 mOhm RDS(on), the gate must be driven to at least -10V relative to source. Driving the gate with only -5V can double or triple the on-resistance, causing excessive conduction loss and thermal runaway. In high-side P-channel circuits, ensure the gate driver can pull the gate to the full positive rail plus VGS to fully turn the device off.
The D2PAK footprint requires substantial drain copper to carry high currents. Use 2 oz copper on the drain layer, with a pad area of at least 100 mm² under and around the tab. Multiple thermal vias (0.3mm drill, 0.6mm pad, 1mm pitch) should connect the top drain copper to inner plane layers. Failure to provide adequate copper reduces the PD rating by 50% or more and may cause intermittent thermal shutdown at peak load.
Compliance Information
PBF suffix indicates Pb-free / RoHS compliance. Not AEC-Q100 qualified as standard; -Q101 suffix variant available for automotive. Halogen-free status not explicitly listed in verified data.
