Infineon Technologies · HEXFET® Series
Infineon HEXFET® IRF4905PBF, P-Channel MOSFET, 55 V Vdss, 74 A Id, 20 mOhm Rds(on) at 10 V, 180 nC Qg, TO-220AB through-hole package, -55°C to 175°C.
MOQ 1 · Tube · RoHS · EIA-481 · DAP/DDP · T/T
| Parameter / Attribute | Specification / Value |
|---|---|
| Series | HEXFET® |
| FET type | P-Channel |
| Mounting | Through Hole |
| Drain to source voltage | 55 V |
| Drive voltage (Max rds on, min rds on) | 10V |
| Current - continuous drain (Id) @ 25°C | 74A (Tc) |
| Power dissipation | 200W (Tc) |
| Operating temperature | -55°C ~ 175°C (TJ) |
| Package | Tube |
| Vgs | ±20V |
| Technology | MOSFET (Metal Oxide) |
| Case | TO-220-3 |
| Vgs(th) (Max) @ id | 4V @ 250µA |
| Rds on (Max) @ id, vgs | 20mOhm @ 38A, 10V |
| Gate charge (Qg) (Max) @ vgs | 180 nC @ 10 V |
| Input capacitance (Ciss) (Max) @ vds | 3400 pF @ 25 V |
Package: TO-220AB · Pin-compatible replacements with immediate Shenzhen spot stock
The P-channel TO-220 row is the high-side switch of practical electronics: loads that must sit above ground and switch on the positive rail, driven straight from logic with a level-shifting transistor and no bootstrap - the circuit simplicity that keeps these parts alive in 12V and 24V designs. The IRF9540 is the classic -100V face of the row (the P-counterpart of the IRF540 lineage) and its on-resistance shows the age; the IRF4905 is the modern brute (-74A at 20 milliohms, but only -55V) and the IRF5210 the middle ground that keeps the 100V rating with triple the original conductance. All three are standard-drive parts, and every substitution in this row is decided by two numbers: rail voltage and the gate drive actually available.
The Modern Brute - Watch the Voltage Ceiling
Shenzhen Spot Stock (24-48h Dispatch)
The high-current member: -55V / -74A with on-resistance about 20 milliohms at -10V gate - ten times the conductance of the IRF9540, with a gate charge (120-180nC) to match.
The -55V ceiling caps it at 48V rails and below - the whole trade against the 9540s -100V.
The 100V Middle Ground
Shenzhen Spot Stock (24-48h Dispatch)
The balanced member: -100V / -40A with about 60 milliohms at -10V - three times the IRF9540s conductance at the same voltage rating and similar power class.
Full -100V class; the direct answer where a 9540 ran hot but the rail forbids the 4905.
The Lighter Original Sibling
Shenzhen Spot Stock (24-48h Dispatch)
The -100V / -12A member of the same original generation: the same vintage 200-milliohm-class on-resistance at lower current - the part where a 9540 design was already at the edge.
Same -100V class.
Q: What is the difference between IRF9540 and IRF4905?
A: Voltage and conductance: IRF9540 is -100V / -19A at about 200 milliohms, IRF4905 is -55V / -74A at about 20. The 4905 is the modern low-loss part but only suits rails to 48V; the 9540 survives the higher-voltage rails it was designed for.
Q: Can I drive an IRF9540 directly from a 5V microcontroller?
A: Not properly - the family is standard-drive (on-resistance at -10V gate). Use an NPN or small-MOSFET level shifter with a pull-up to the source rail so the gate actually swings below the source. Direct 5V drive leaves the channel partially enhanced and the part hot.
Q: When should I use N-channel instead of P-channel for high-side switching?
A: Above roughly 5-10A of load: N-channel conductance is several times better at equal die area, in exchange for a bootstrap or charge-pump gate supply. The P-channel row wins below that by circuit simplicity, not by efficiency.
The IRF4905PBF: Gate charge totals 180 nC at 10 V, so the gate driver must supply enough peak current to charge the input capacitance (3400 pF typical at 25 V) within the target switching interval.
The through-hole TO-220AB package suits point-of-load or chassis-mount layouts where a screw or clip secures the tab to a heatsink.
