IRF4905PBF - 55V P-Channel 74A HEXFET MOSFET | Infineon
MPN: IRF4905PBF ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.45 | $2.45 |
| 10 | $2.1 | $21.00 |
| 100 | $1.75 | $175.00 |
| 500 | $1.42 | $710.00 |
| 1,000 | $1.18 | $1,180.00 |
| 3,000 | $0.95 | $2,850.00 |
IRF4905PBF Overview
A P-channel MOSFET is a voltage-controlled device whose drain-source conduction is triggered by a gate-source voltage of the same polarity as the source (negative for P-channel). Because P-channel devices can be driven by pulling the gate low relative to the source, they are widely used as high-side switches in half-bridge and buck topologies, where their gate-drive simplicity avoids the bootstrap network required by an N-channel high-side switch. In the broader taxonomy, the IRF4905PBF sits as: MOSFET -> power MOSFET -> P-channel MOSFET -> discrete semiconductor -> power management building block.
Key specifications include -55V drain-source breakdown (VDS), -74A continuous drain current at TC (ID, with package-limited pulse rating higher), 20 mΩ max on-resistance at VGS=-10V, 120 nC total gate charge, and a fast switching edge suitable for 100 kHz-class converters. The TO-220AB package offers three through-hole leads (Gate, Drain, Source from left to right when viewing the front of the package) and a metal tab that doubles as the drain connection and a thermal dissipation path with θJC of approximately 1.0 °C/W.
Architecturally, the device uses Infineon's HEXFET cellular planar process, which places thousands of parallel MOSFET cells across the die to minimize RDS(on) while maintaining SOA robustness. The fifth-generation refinement shrinks cell pitch, reduces gate charge, and improves avalanche energy rating compared to earlier generations, enabling higher current density and more efficient switching.
Typical applications include high-side switching in motor drives (H-bridge high-side), battery protection and reverse-polarity protection circuits, load switches and power OR-ing, DC-DC converter synchronous-rectifier high-side replacements, and audio amplifier output stages where high current pulses demand low on-resistance to minimize dissipation.
A critical design consideration is the gate-drive requirement: because this is a P-channel device, the gate must be pulled at least -10V below the source to fully enhance. Designers must ensure the gate driver can swing between VSOURCE and VSOURCE-10V or lower, accounting for the source-follower configuration when the device is used as a high-side switch.
This page synthesizes distributor pricing, drop-in TO-220AB alternatives, and practical thermal/SOA guidance not found in the manufacturer datasheet alone.
Drop-in alternatives for IRF4905PBF — 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 IRF4905PBF (same form factor and footprint) — differing in Package, Technology, Total Gate Charge (Qg), Lead-Free / RoHS, Operating Junction Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
IRF4905SPBF
✅ Drop-In✓ In Stock
$1.18 / Unit
View Datasheet →AUIRF4905
✅ Drop-In📋 Reference alternative (not in catalog)
IRF4905LPBF
✅ Drop-In✓ In Stock
$0.98 / Unit
View Datasheet →STP80PF55
✅ Drop-In📋 Reference alternative (not in catalog)
SUP75P06
✅ Drop-In📋 Reference alternative (not in catalog)
IRF9540N
✅ Drop-In📋 Reference alternative (not in catalog)
IRF4905PBF Maximum Ratings & Electrical Characteristics
| FET Type | P-Channel |
| Technology | HEXFET (IR MOSFET) |
| Drain-Source Voltage (VDS) | -55 V |
| Continuous Drain Current (ID) at TC | -74 A |
| Power Dissipation (PD) at TC | 200 W |
| On-Resistance RDS(on) max at VGS=-10V | 20 mΩ |
| Total Gate Charge (Qg) | 120 nC |
| Operating Temperature Range | -55 °C to +175 °C (junction) |
| Package | TO-220AB (through-hole) |
| Pin Configuration | Gate - Drain - Source (left to right) |
| Mounting Type | Through Hole |
| Lead-Free / RoHS | Yes (PBF suffix = lead-free, RoHS compliant) |
| MSL Level | 1 (not moisture-sensitive for TO-220) |
IRF4905PBF Pin Configuration
| Pin 1 | Gate (G) — MOSFET gate; drive to VSOURCE - 10V or lower for full enhancement |
| Pin 2 | Drain (D) — MOSFET drain; metal tab is internally connected to drain |
| Pin 3 | Source (S) — MOSFET source; reference point for VGS |
Safe Operating Area (DC)
Typical Applications
IRF4905PBF is suitable for 7 applications: DC Motor Drive H-Bridge, Battery Reverse-Polarity Protection, High-Side Load Switch / Power OR-ing, Audio Amplifier Output Stage, Solar Charge Controller / Battery Management, Automotive 12V/24V Load Switching, Synchronous Rectifier / DC-DC Converter High-Side.
DC Motor Drive H-Bridge
The IRF4905PBF is widely deployed as the high-side P-channel switch in H-bridge motor drivers, where its P-channel polarity eliminates the need for a bootstrap or charge-pump network that an N-channel high-side would otherwise require. With -55V VDS it tolerates 24V battery rails plus inductive flyback spikes, and 20 mΩ RDS(on) keeps conduction loss low enough to deliver 30A continuous to a brushed DC motor without an oversized heatsink. Place a 10kΩ pull-up from gate to source to hold the device off during power-up and a flyback diode across the motor inductance. Pair with a complementary N-channel low-side (e.g. IRF540N) for a complete H-bridge. Switching frequency up to 50 kHz is achievable thanks to the 120 nC total gate charge.
Recommended
Battery Reverse-Polarity Protection
The IRF4905PBF excels in reverse-polarity protection (RPP) circuits where a P-channel MOSFET is placed in series with the battery positive rail. The source ties to VBAT+ and the drain to the system load; under correct polarity the gate is pulled low through a Zener/resistor divider, turning the MOSFET on and powering the load with only the IRF4905PBF's 20 mΩ on-resistance as the loss. Under reverse polarity, the gate-source voltage reverses and the device self-biases off, blocking current. The -55V VDS provides 30V of headroom above a 12V or 24V battery, comfortably absorbing load-dump transients. A 100kΩ gate-source resistor ensures defined off-state behaviour when the system is unpowered.
Recommended
High-Side Load Switch / Power OR-ing
For high-current load switching and redundant power OR-ing in 12V/24V systems, the IRF4905PBF serves as a low-loss high-side switch. Driven by a logic-level signal through a small-signal NPN transistor (to level-shift from 3.3V to -10V gate drive), the P-channel MOSFET eliminates the complexity of charge-pump-driven N-channel high-side switches. The 20 mΩ RDS(on) at -10V VGS yields only 1W of dissipation at 7A load, well within the 200W package rating. For redundant power OR-ing, two IRF4905PBF devices can be paralleled (with source-ballast resistors) to share 30A continuously with under 0.5W loss per device.
Recommended
Audio Amplifier Output Stage
In class-AB audio amplifier output stages, the IRF4905PBF can serve as the upper P-channel output device in a complementary pair with an N-channel MOSFET (such as IRF240/IRF540N). The HEXFET process delivers a 20 mΩ on-resistance that minimizes crossover-region distortion by keeping VDS saturation low even at high peak currents. Audio amplifiers frequently demand 10-20A peak currents into low-impedance loads (4Ω); the IRF4905PBF's -74A rating provides ample headroom. Bias the gate at a small quiescent current (50-100 mA) to stay in class-AB operation and avoid crossover distortion. The -55V VDS also tolerates supply rails up to ±25V.
Recommended
Solar Charge Controller / Battery Management
In solar battery charge controllers, the IRF4905PBF acts as a low-side blocking MOSFET (P-channel variant tied to ground-side) or as the high-side disconnect switch in MPPT converters. The -55V rating comfortably handles 12V/24V battery banks plus PV panel open-circuit voltage (up to 40V for 24V systems). The HEXFET ruggedness allows the device to absorb avalanche energy during sudden PV input disconnection, a critical feature when the controller's input capacitor bank dumps charge back through the switch. With 20 mΩ RDS(on), the conduction loss at 20A charge current is just 8W, easily manageable on a TO-220 clip-mount heatsink.
Recommended
Automotive 12V/24V Load Switching
The IRF4905PBF (or its automotive-qualified sibling AUIRF4905) is a workhorse for automotive 12V/24V load switching - controlling lamps, solenoids, fans, and seat heaters via body-control modules. The -55V VDS comfortably tolerates the +35V load-dump transient specified by ISO 7637-2, while the 20 mΩ RDS(on) keeps dissipation low for high-current loads (e.g. headlamp bulbs at 10A, fuel pumps at 15A). For AEC-Q100/AEC-Q101 qualified designs, choose the AUIRF4905 variant, which uses the same die but with automotive reliability testing. Mount on a TO-220 clip heatsink bonded to the chassis for ground-referenced cooling.
Recommended
Synchronous Rectifier / DC-DC Converter High-Side
In buck-derived DC-DC converter topologies, the IRF4905PBF can serve as a P-channel synchronous rectifier (replacing a Schottky diode) or as the high-side switch in a P-channel/N-channel buck. Its 120 nC gate charge and HEXFET process enable efficient switching at 100-200 kHz with acceptable switching losses. The -55V VDS supports 24V input rails with comfortable margin. Because P-channel high-side switches do not require bootstrap circuits, the gate-drive circuitry is simpler than with an N-channel high-side, reducing total BOM cost and PCB area. Add a 100V TVS across drain-source for additional protection against transformer-coupled transients.
Recommended
Recommended Products Summary
Engineering reference data for IRF4905PBF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | IRF4905SPBF | AUIRF4905 | IRF4905LPBF | STP80PF55 | SUP75P06 |
|---|---|---|---|---|---|---|
| Brand | Infineon | Infineon | Infineon | Infineon | STMicroelectronics | Vishay Intertechnology |
| Package | TO-220AB | TO-220AB - same | TO-220AB - same | TO-220AB - same | TO-220AB - same | TO-220AB - same |
| Polarity | P-Channel | P-Channel | P-Channel | P-Channel | P-Channel | P-Channel |
| Drain-Source Voltage (VDS) | -55 V | -55 V | -55 V | -55 V | -55 V | -60 V |
| Continuous Drain Current (ID) | -74 A | -74 A | -74 A | -74 A | -80 A | -75 A |
| On-Resistance RDS(on) max | 20 mΩ | 20 mΩ | 20 mΩ | 20 mΩ | 16 mΩ | 14 mΩ |
| Automotive Qualified | No (industrial grade) | No | Yes (AEC-Q101) | No | No | No |
| RoHS / Lead-Free | Yes (PBF suffix) | Yes | Yes | Yes | Yes | Yes |
Key Differentiators
- Automotive-qualified equivalent variant available within the same product family (vs STP80PF55)
- Lower on-resistance than legacy alternatives (vs IRF9540N)
- P-channel polarity eliminates bootstrap/charge-pump high-side drive complexity (vs N-channel MOSFET (IRF540N))
Design Notes
Estimated: At a continuous load of 30A through the IRF4905PBF, conduction loss is P = I²·RDS(on) = 30²·0.020 = 18W. With TO-220AB on a clip-mount heatsink (θSA ≈ 15 °C/W) plus junction-to-case (θJC ≈ 1.0 °C/W), total θJA ≈ 16 °C/W. Junction temperature rise = 18·16 = 288°C above ambient, which exceeds the 175°C maximum. Therefore, sustained 30A operation requires either a larger heatsink (θSA < 7 °C/W) or forced-air cooling. At 15A continuous, loss is 4.5W and junction rise is 72°C, which is acceptable up to 100°C ambient.
Do not drive the gate of the IRF4905PBF directly from a 3.3V or 5V microcontroller GPIO. The P-channel device requires the gate to be pulled at least -10V below the source to fully enhance. A logic-level GPIO cannot provide this. Use a small-signal NPN transistor (BSS123) or gate-driver IC to level-shift the control signal. Add a 10kΩ pull-up resistor from gate to source to ensure the MOSFET stays off during power-up and undefined logic states. Without this resistor, the gate can float and the device can partially turn on, causing shoot-through or excessive quiescent current.
When laying out a TO-220AB footprint, ensure the drain pad (the metal tab) has a generous copper pour on both sides of the PCB (or use a clip-mount heatsink) to keep junction temperature low. Source and gate traces should be short and direct to minimize parasitic inductance that could cause gate-oscillation during fast switching edges. Place the gate-drive resistor (typically 10-100Ω) close to the gate pin. For high-current applications (>20A), use 2oz copper or thicker on the source and drain traces to limit voltage drop and copper heating.
The IRF4905PBF's 120 nC total gate charge and fast switching edges can couple back into the gate drive circuit through the drain-gate capacitance (Cgd, also called Miller capacitance). This may cause unintended turn-on or 'Miller turn-on' in half-bridge configurations. Add a 10-100Ω gate resistor to slow the switching edge if ringing is observed, and place a small ceramic bypass (10-100nF) directly at the gate-source pins to shunt high-frequency noise. For half-bridge designs, add a dead-time circuit to prevent shoot-through during the high-to-low and low-to-high transitions.
Compliance Information
IRF4905PBF is RoHS compliant per the PBF suffix (lead-free). For AEC-Q100/AEC-Q101 automotive qualification, choose the AUIRF4905 variant, which uses the same die. Reach compliance confirmed by Infineon product page. Halogen-free per Infineon declarations.
