onsemi FGH75T65SHD-F155 IGBT: Datasheet, Application Circuit, and Thermal Management Guide
The onsemi FGH75T65SHD-F155 represents a high-performance Insulated Gate Bipolar Transistor (IGBT) engineered for demanding high-power switching applications. This device combines low saturation voltage with fast switching capabilities, making it an ideal choice for systems such as industrial motor drives, renewable energy inverters, and uninterruptible power supplies (UPS). This article provides a detailed overview of its key specifications, a typical application circuit, and essential thermal management guidelines.
Datasheet Overview and Key Specifications
The FGH75T65SHD-F155 is part of onsemi's field stop trench-gate IGBT series, which is optimized for low losses and high efficiency. Its key electrical characteristics, as defined in the datasheet, include:
Voltage Ratings: A collector-emitter voltage (VCES) of 650 V and a gate-emitter voltage (VGES) of ±20 V.
Current Ratings: A high collector current (IC) of 75 A at 100°C, with a maximum pulsed current (ICM) of 150 A.
Low Saturation Voltage: VCE(sat) is typically 1.85 V (at IC = 75 A, VGE = 15 V), which directly contributes to reduced conduction losses.
Fast Switching Speed: The device features low turn-on and turn-off times, which help in minimizing switching losses and enabling higher frequency operation.
An integral part of this package is the co-packaged ultra-fast soft recovery diode. This diode is critical for managing reverse recovery currents and enhancing the overall reliability and efficiency of the system, particularly in inductive load switching scenarios.
Typical Application Circuit
A common half-bridge circuit configuration, central to most inverter designs, is a primary application for this IGBT. In such a setup, two FGH75T65SHD-F155 devices are used in series between the positive and negative DC bus rails. The midpoint between them connects to the load (e.g., a motor winding).
Critical external components for driving each IGBT include:
1. Gate Driver Circuit: A dedicated gate driver IC is mandatory to provide the necessary current to charge and discharge the IGBT's input capacitance rapidly. A gate resistor (RG) of typically 2.2Ω to 4.7Ω is used to control the switching speed and dampen ringing.
2. Clamping Circuits: A transient voltage suppressor (TVS) or an RCD snubber network across the collector and emitter is often employed to clamp voltage spikes caused by parasitic inductance in the circuit, protecting the IGBT from overvoltage stress.
Proper PCB layout is paramount, requiring low-inductance power loops and separated power and control ground planes to ensure stable and efficient operation.
Thermal Management Guide
Effective heat dissipation is non-negotiable for maximizing the performance and lifespan of the FGH75T65SHD-F155. Its low junction-to-case thermal resistance (RθJC) of 0.25 °C/W indicates good heat transfer from the silicon die to the baseplate.
Key thermal management strategies:
Heatsink Selection: A suitably sized aluminum heatsink with a low thermal resistance (RθSA) must be selected based on the maximum power dissipation and ambient temperature. The total thermal resistance from junction to ambient (RθJA) must be low enough to keep the maximum junction temperature (TJ) safely below its rated 175°C under all operating conditions.
Interface Material: A high-quality thermal interface material (TIM), such as thermal grease or a phase-change pad, must be applied between the IGBT module's baseplate and the heatsink to eliminate air gaps and minimize thermal contact resistance.
Cooling Method: Forced air cooling with a fan is highly recommended for high-power applications. For the most demanding systems, liquid cooling may be necessary to achieve the required heat transfer.
ICGOODFIND Summary
The onsemi FGH75T65SHD-F155 IGBT is a robust and efficient solution for high-power conversion. Its low VCE(sat) and fast switching characteristics ensure high system efficiency. Successful implementation hinges on a robust gate driving design, careful PCB layout to minimize stray inductance, and, most critically, a comprehensive thermal management strategy to dissipate heat effectively and ensure long-term reliability.
Keywords:
1. IGBT
2. Thermal Management
3. VCE(sat)
4. Gate Driver
5. Switching Losses
