IRFS4321TRLPBF - 150V 85A N-Ch HEXFET MOSFET D2PAK | Infineon
MPN: IRFS4321TRLPBF ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.52 | $3.52 |
| 10 | $2.99 | $29.90 |
| 100 | $2.41 | $241.00 |
| 500 | $2.05 | $1,025.00 |
| 1,000 | $1.73 | $1,730.00 |
Drop-in alternatives for IRFS4321TRLPBF — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
IRFS4321TRRPBF
✅ Drop-In✓ In Stock
$2.97 / Unit
View Datasheet →IRFS4321PbF
✅ Drop-In📋 Reference alternative (not in catalog)
VBL1151N
✅ Drop-In📋 Reference alternative (not in catalog)
IRFS4321TRLPBF Maximum Ratings & Electrical Characteristics
| FET Type | N-Channel MOSFET, Metal Oxide |
| Drain-to-Source Voltage (VDS) | 150 V |
| Continuous Drain Current (ID) at Tc=25C | 85 A |
| RDS(on) Max at VGS=10V | 15 mOhm |
| Gate-to-Source Voltage (VGS) Max | ±20 V |
| Total Gate Charge (Qg) Typ | 71 nC |
| Total Gate Charge (Qg) Max | 110 nC |
| Power Dissipation (PD) at Tc=25C | 350 W |
| Thermal Resistance Junction-to-Case (RθJC) Max | 0.45 C/W |
| Thermal Resistance Junction-to-Case (RθJC) End-of-Life | 0.65 C/W (after 1000 cycles -55C to +150C) |
| Operating Junction Temperature | -55C to +175C |
| Package | TO-263-3, D2PAK (2 Leads + Tab), TO-263AB |
| Mounting Type | Surface Mount |
| Technology | IR HEXFET (IR MOSFET) |
| RoHS Status | Compliant |
IRFS4321TRLPBF Pin Configuration
| Pin 1 | Gate — Gate control input (MOSFET gate terminal) |
| Pin 2 | Drain — Drain terminal (internally connected to the metal tab) |
| Pin 3 | Source — Source terminal (MOSFET return) |
| Pin Tab | Drain — Metal tab - electrically connected to Drain (pin 2) and serves as primary thermal path |
Safe Operating Area (DC)
Typical Applications
IRFS4321TRLPBF is suitable for 7 applications: SMPS Synchronous Rectification, Uninterruptible Power Supply (UPS), Motion Control / Motor Drive, Hard-Switched High-Frequency Converters, Battery Management Systems (BMS) Discharge Path, Solar Inverter / PV Input Stage, Automotive 48 V Mild-Hybrid Systems.
SMPS Synchronous Rectification
The IRFS4321TRLPBF is well-matched to 100-150 V class synchronous rectifier positions in telecom and server SMPS designs. Its 150 V VDS rating gives ample avalanche margin above a 100 V continuous bus, while 15 mOhm max RDS(on) at VGS = 10 V keeps conduction loss at approximately 19 W per device at 50 A load. The 71 nC typical Qg allows 100-200 kHz switching transitions with a standard 1-2 A gate driver, and the D2PAK package dissipates 350 W with proper copper area, making it ideal for high-current half-bridge and full-bridge synchronous stages.
Recommended
Uninterruptible Power Supply (UPS)
In on-line UPS and line-interactive battery backup systems operating on 48-96 V battery stacks, the IRFS4321TRLPBF serves as the low-side switch in the bidirectional inverter stage. Its 85 A continuous Tc rating supports 5-10 kVA UPS designs with proper thermal management, while 15 mOhm RDS(on) limits conduction loss to under 1.5% of throughput power. The 0.45 C/W RθJC enables compact heatsinking in rack-mounted UPS chassis, and the 150 V VDS provides over-voltage margin for transient battery load-dump conditions.
Recommended
Motion Control / Motor Drive
The IRFS4321TRLPBF is suitable for 96-144 V BLDC and three-phase motor drives in industrial automation and robotics, where it can serve as the low-side or high-side switch in 50-100 A class inverter bridges. Its 71 nC typical Qg keeps switching loss manageable at 20-50 kHz PWM frequencies typical of motor control, while 85 A Tc supports continuous motor currents up to 60 A per phase with proper heatsinking. The D2PAK package is industry-standard for motor-drive power stages and integrates easily with FR4 or IMS substrates.
Recommended
Hard-Switched High-Frequency Converters
For hard-switched DC-DC converter topologies operating at 100-300 kHz in telecom and industrial applications, the IRFS4321TRLPBF's combination of 15 mOhm RDS(on) and 71 nC Qg achieves a favorable figure-of-merit (FOM = RDS(on) × Qg ≈ 1.07 nC·Ohm) for high-frequency efficiency. Its 150 V VDS supports 100-120 V input bus applications including 110 V rectified industrial supply rails. The HEXFET cell structure provides robust avalanche capability for unclamped inductive switching events common in hard-switched topologies.
Recommended
Battery Management Systems (BMS) Discharge Path
In 48-96 V lithium-ion battery management systems for e-mobility light EVs and energy storage, the IRFS4321TRLPBF can serve as the main discharge MOSFET or back-to-back protection switch. Its 85 A Tc rating suits 3-5 kW continuous discharge systems, and 15 mOhm RDS(on) per device minimizes parasitic conduction loss during normal operation. The 150 V VDS provides over-voltage protection margin for series-stack battery voltages up to 120 V nominal, and the D2PAK package is easily inspected and reworked during BMS prototyping.
Recommended
Solar Inverter / PV Input Stage
In solar micro-inverters and string-inverter input stages operating on 60-150 V PV panel strings, the IRFS4321TRLPBF can be used as the buck-stage main switch or boost-stage synchronous rectifier. Its 15 mOhm RDS(on) at 10 V VGS achieves 98%+ peak efficiency when paired with proper gate driving, and the 150 V VDS handles open-circuit PV voltage transients. The D2PAK package's thermal mass smooths out thermal cycling from intermittent cloud-shading events, extending system lifetime in outdoor PV installations.
Recommended
Automotive 48 V Mild-Hybrid Systems
In 48 V mild-hybrid automotive systems (MHEV) where bus voltages can reach 60-80 V steady-state with transient spikes above 100 V, the IRFS4321TRLPBF can serve in DC-DC converter stages between the 48 V bus and 12 V battery. While not AEC-Q100 qualified, its 150 V VDS rating and robust D2PAK construction provide voltage margin and thermal performance similar to automotive-grade alternatives. Designers targeting full automotive qualification should evaluate AEC-Q100 parts; the IRFS4321TRLPBF is more commonly deployed in non-automotive industrial 48 V systems.
Recommended
Recommended Products Summary
Engineering reference data for IRFS4321TRLPBF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | IRFS4321TRRPBF | IRFS4321PbF | VBL1151N |
|---|---|---|---|---|
| Brand | Infineon | Infineon | Infineon | VBsemi |
| Package | D2PAK (TO-263-3) | D2PAK (TO-263-3) | D2PAK (TO-263-3) | D2PAK (TO-263-3) |
| VDS Max | 150 V | 150 V | 150 V | 150 V |
| Continuous Drain Current (Tc=25C) | 85 A | 85 A | 85 A | 85 A (class) |
| RDS(on) Max at VGS=10V | 15 mOhm | 15 mOhm | 15 mOhm | [DATA_NEEDED] |
| Total Gate Charge (Qg) Typ | 71 nC | 71 nC | 71 nC | [DATA_NEEDED] |
| Power Dissipation (Tc=25C) | 350 W | 350 W | 350 W | [DATA_NEEDED] |
| Thermal Resistance (RθJC) Max | 0.45 C/W | 0.45 C/W | 0.45 C/W | [DATA_NEEDED] |
| Operating Junction Temperature | -55C to +175C | -55C to +175C | -55C to +175C | [DATA_NEEDED] |
| RoHS Compliance | Compliant | Compliant | Compliant | [DATA_NEEDED] |
Key Differentiators
- Higher continuous drain current at 150 V VDS than typical alternatives (vs FDB2532)
- Low 71 nC typical Qg for high-frequency switching (vs VBL1151N)
- Established manufacturer supply chain and long-term availability (vs VBL1151N (VBsemi))
Design Notes
The D2PAK package has RθJC = 0.45 C/W per Infineon's datasheet, which means at 50 A conduction loss (P = I²R = 50² × 0.015 = 37.5 W), junction temperature rises 17C above case. If the case is held at 100C via a forced-air heatsink, the junction reaches 117C - within the 175C rating. For continuous 85 A operation, an external forced-air heatsink or substantial PCB copper area (minimum 6 sq inches at 2 oz copper) is required to keep RθJA below 2 C/W. End-of-life RθJC after 1000 thermal cycles rises to 0.65 C/W - factor this into long-life industrial designs requiring 10+ year service life.
Use a minimum 2 oz copper pour under the D2PAK tab with thermal vias connecting top-side copper to inner plane layers. The drain tab is internally connected to pin 2; the copper pour also serves as the drain electrical connection. Place gate-drive components within 25 mm of the gate pin to minimise gate-loop inductance and suppress VGS ringing; add a 10 Ohm gate-source resistor close to the gate pin to prevent unintended turn-on during dv/dt transients.
Do not exceed VGS = ±20 V maximum ratings - typical gate-drive ICs output 12 V or 15 V which is safe, but isolated gate drivers with bootstrap supplies can overshoot. Add a 10 kΩ pull-down on the gate to source to ensure the MOSFET stays off during controller power-up. When paralleling multiple IRFS4321TRLPBF devices, ensure symmetric PCB layout and matched gate-drive loops to prevent current imbalance - the 15 mOhm RDS(on) has a typical positive temperature coefficient that helps thermal balancing.
Compliance Information
RoHS and REACH compliant per Infineon product page; Pb-free finish (PbF suffix in part number confirms lead-free). Not AEC-Q100 qualified - for automotive applications requiring AEC-Q100, choose an automotive-grade Infineon part instead.
