BSM35GB120DLC: A Technical Review of Infineon’s 1200V 35A IGBT Module

BSM35GB120DLC | 1200V 35A Dual IGBT Module by Infineon

Introduction to the BSM35GB120DLC IGBT Module

This BSM35GB120DLC is a half-bridge IGBT module from Infineon, engineered with Trench and Fieldstop IGBT3 technology to provide a well-balanced performance for industrial power conversion systems. It integrates two series-connected IGBTs with anti-parallel diodes in a standard industrial housing, offering a robust foundation for building efficient and reliable inverters and drives. The module’s design focuses on achieving low conduction losses while maintaining controlled switching characteristics for effective thermal management.

• Core Specifications: 1200V | 35A (Nominal) | VCE(sat) 2.4V (typ. @ 125°C)
• Key Advantages: Low conduction losses reduce operational heat, and an integrated NTC thermistor enables precise temperature monitoring for enhanced system protection.

The inclusion of a fast recovery diode and low thermal resistance from junction to case simplifies the thermal design process, allowing engineers to optimize heatsink selection for long-term operational stability.

Download the Official BSM35GB120DLC Datasheet (PDF)

Technical Analysis of Core Features

The BSM35GB120DLC module’s performance is rooted in Infineon’s Trench-Fieldstop IGBT3 technology. This structure provides a low collector-emitter saturation voltage (VCE(sat)), which is specified as a typical value of 2.4V at a junction temperature of 125°C and nominal current. This characteristic directly translates to lower power dissipation during the on-state, a critical factor in applications with high duty cycles such as motor drives and power supplies.

Effective thermal dissipation is central to power module reliability. The module specifies a thermal resistance from junction to case (RthJC) of 0.8 K/W for each IGBT. This parameter can be compared to the width of a pipe for draining heat; a lower value signifies a wider pipe, allowing heat to be extracted more efficiently from the active silicon to the heatsink. This efficient heat transfer, combined with a maximum junction temperature of 150°C, provides a solid thermal operating margin.

For enhanced system-level safety and control, the BSM35GB120DLC incorporates an NTC thermistor. This allows the drive control board to monitor the module’s baseplate temperature in real-time. This data is essential for implementing over-temperature protection, preventing catastrophic failures, and understanding the system’s operational state. To learn more about thermal monitoring, explore the critical role of the integrated NTC in IGBT module safety.

Optimized Application Scenarios

The electrical and thermal characteristics of this module make it well-suited for several medium-power applications.

• AC Motor Drives: The half-bridge configuration is the fundamental building block for three-phase inverters, and its efficiency at typical motor frequencies reduces cooling requirements.
• Uninterruptible Power Supplies (UPS): A 1200V blocking voltage provides a high safety margin for systems connected to the grid, while low conduction losses improve battery runtime.
• Welding Power Supplies: The module’s specified short-circuit withstand time of 10 µs provides the necessary robustness to handle the demanding, and often unpredictable, load conditions found in welding applications.
• Solar Inverters: Efficient power conversion is paramount in renewable energy systems, and the module’s balanced loss profile contributes to maximizing energy yield.

This module is best matched for systems requiring a robust 1200V platform with moderate switching frequencies where both conduction losses and thermal performance are key design drivers.

Key Specifications for BSM35GB120DLC

Electrical Characteristics (per IGBT, unless otherwise specified)
Collector-Emitter Voltage (V_CES)	1200 V
Continuous Collector Current (I_C @ Tc=80°C)	35 A
Collector-Emitter Saturation Voltage (V_CE_sat, typ. @ 35A, Tvj=125°C)	2.40 V
Gate-Emitter Threshold Voltage (V_GE(th))	5.0 V (min) to 6.5 V (max)
Short Circuit Withstand Time (t_psc)	10 µs
Thermal and Mechanical Characteristics
Thermal Resistance, Junction-to-Case (R_thJC, IGBT)	0.8 K/W
Thermal Resistance, Junction-to-Case (R_thJC, Diode)	1.2 K/W
Operating Junction Temperature (T_vj_op)	-40°C to +150°C
Mounting Torque (Terminals, M5)	2.5 – 5.0 Nm
Isolation Test Voltage (V_ISOL)	2.5 kV (RMS, f=50Hz, t=1 min)

Engineer’s FAQ

1. What are the key thermal design considerations for the BSM35GB120DLC?

The primary consideration is ensuring the junction temperature remains below the 150°C maximum. To do this, calculate the total power loss (conduction + switching) for your specific application. Use the RthJC (0.8 K/W for IGBT, 1.2 K/W for diode) and the thermal resistance of your thermal interface material (TIM) and heatsink (RthCS + RthSA) to determine the required heatsink performance. The integrated NTC should be used to validate the thermal design under real-world load conditions.

2. What is the recommended mounting torque, and why is it important?

The datasheet specifies a mounting torque of 2.5 – 5.0 Nm for the M5 electrical terminals. Adhering to this range is critical. Insufficient torque can lead to high contact resistance, causing localized overheating and potential failure. Excessive torque can induce mechanical stress on the module’s ceramic substrate, potentially causing it to crack and leading to isolation failure. Always use a calibrated torque wrench for installation.

3. Does this module include a freewheeling diode (FWD)?

Yes, the BSM35GB120DLC is a half-bridge module that includes a silicon freewheeling diode co-packaged with each IGBT. The diode is optimized for fast and soft recovery, which is crucial for minimizing turn-on losses in the opposing IGBT and reducing EMI. The datasheet specifies its forward voltage (V_F) as 2.0V (typ. at 125°C).

Enabling Robust Power Designs

The BSM35GB120DLC provides a technically sound and reliable component for power electronics engineers. By integrating proven Trench-Fieldstop IGBT3 technology with essential features like an NTC thermistor and a robust package, this module facilitates the design of efficient, controllable, and thermally stable power conversion systems for a range of industrial applications. For more insights on power semiconductor technologies, see our articles on the IGBT vs. SiC vs. GaN showdown.