Infineon
IRFS4321PBF
StrongIRFET
Package: D2PAK
150 V 170 A StrongIRFET MOSFET in D2PAK with 3.4 mOhm RDSon for high-current synchronous rectifiers and battery switches.
Overview
The Infineon IRFS4321PBF is a 150 V, 170 A StrongIRFET(TM) N-channel MOSFET in the surface-mount D2PAK (TO-263) package, engineered for synchronous rectification, ORing switch, and high-current DC bus switching applications where minimal conduction resistance and robust avalanche ruggedness are equally important. Its maximum RDSon of 3.4 mOhm at VGS = 10 V positions it at the top of the 150 V silicon MOSFET performance tier, enabling DC/DC converters and battery management systems to achieve rectifier stages with power densities previously requiring copper-bonded die technologies. The StrongIRFET process employs a deep trench cell architecture that concentrates the channel width per unit area, allowing the D2PAK die to handle 170 A continuous drain current with a junction temperature limit of 175 degreesC. The large molded package die-pad provides a junction-to-case thermal resistance of only 0.65 K/W, enabling heat dissipation through PCB copper planes or clip-mount heatsinks without through-hole mounting hardware. Gate charge Qg is specified at 230 nC at VGS = 10 V - a relatively high value that reflects the large die size - so gate driver current capability should be sized accordingly. The device also exhibits excellent unclamped inductive switching (UIS) ruggedness with a single-pulse avalanche energy rating of 3 J at 25 degreesC, providing margin against inductive load switching transients in high-current motor drives and DC disconnect switches. BeiLuo distributes the IRFS4321PBF in volume with documented lot traceability and provides PCB layout templates for optimal thermal performance with D2PAK copper-pour cooling.
Specifications
| Parameter | Value | Unit |
|---|---|---|
| Drain-Source Voltage VDS | 150 | V |
| Continuous Drain Current ID (25 degreesC) | 170 | A |
| RDSon Max (VGS=10V) | 3.4 | mOhm |
| Gate Charge Qg (VGS=10V) | 230 | nC |
| Gate Threshold Voltage VGSth | 2.0 - 4.0 | V |
| Single-Pulse Avalanche Energy EAS | 3000 | mJ |
| Thermal Resistance RthJC | 0.65 | K/W |
| Maximum Junction Temperature | 175 | degreesC |
| Package | D2PAK (TO-263) | |
| Body Diode Forward Voltage VSD | 1.3 | V |
Applications
- High-Current Synchronous Rectifiers
- Battery Management ORing Switches
- DC Motor Drive H-Bridges
- Server Rack Power Distribution
- Telecom -48 V Bus Converters
Documents & Downloads
- IRFS4321PBF Datasheet (0.7 MB)
- BeiLuo MOSFET Selection Guide (1.0 MB)
Frequently Asked Questions
What gate driver current is recommended to drive the IRFS4321PBF at high switching frequencies?
The IRFS4321PBF has a total gate charge Qg of 230 nC at 10 V drive. To achieve a 100 ns rise time at a 100 kHz switching frequency, a peak gate source current of approximately 2.3 A is required. Dedicated gate driver ICs rated for 2 to 4 A peak output - such as the Infineon EiceDRIVER 2EDL series - are appropriate. Reducing the switching frequency to 20 to 50 kHz allows smaller gate drivers, trading switching losses for driver simplicity in cost-sensitive designs.
Can the IRFS4321PBF be used as a synchronous rectifier in a bidirectional battery charger?
Yes. The IRFS4321PBF's 3.4 mOhm maximum RDSon and 170 A current rating make it well-suited for synchronous rectification stages in bidirectional on-board charger (OBC) designs up to approximately 11 kW at 48 V bus voltage. The body diode's forward voltage of 1.3 V is relatively high for a synchronous rectifier, so gate drive timing should enable the MOSFET channel before body-diode conduction begins in each half-cycle, minimizing dead-time losses.
How should D2PAK devices like the IRFS4321PBF be thermally managed on a PCB?
The D2PAK (TO-263) exposed die-pad should be soldered to a dedicated copper pour area of at least 1,000 mm2 on the top PCB layer. For power dissipation above 5 W, thermal vias connecting the top copper pour to an internal ground plane reduce the board-to-ambient resistance significantly. A clip-mount heatsink adhesively bonded over the molded body further reduces thermal resistance for dissipation above 10 W. BeiLuo's FAE team can provide a thermal model in PLECS or Simscape for accurate junction temperature estimation.
Is the IRFS4321PBF rated for automotive applications?
The standard IRFS4321PBF is an industrial-grade device rated for junction temperatures to 175 degreesC but not specifically AEC-Q101 qualified. For automotive applications requiring full AEC-Q101 qualification and PPAP documentation, Infineon offers the AUIRFS4321 with equivalent electrical parameters but the full automotive qualification package. BeiLuo can source both variants - please specify your qualification requirement when requesting a quote.
What is the avalanche ruggedness of the IRFS4321PBF and why does it matter?
The IRFS4321PBF is rated for a single-pulse avalanche energy EAS of 3,000 mJ at 25 degreesC starting temperature. This specification indicates the device can absorb the energy stored in a stray inductance during unclamped inductive switching without destructive failure. In practical terms, a 100 uH stray inductance with 60 A of inductor current produces an avalanche energy of 180 mJ, well within the rated limit. Avalanche ruggedness is particularly important in motor-drive H-bridges where unexpected current paths can arise during fault conditions.
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