Content last revised on November 20, 2025
CM35MX-24A | 1200V 35A 7-in-1 IGBT Module for Compact Drives
The Mitsubishi CM35MX-24A, a key component in their M-Series of IGBT modules, simplifies thermal design and boosts reliability in compact motor drives with its all-in-one Converter-Inverter-Brake (CIB) topology. This power module integrates a complete drive power stage, offering ratings of 1200V | 35A with a typical VCE(sat) of 1.70V. Its primary engineering benefits are a significantly reduced component count and simplified system-level thermal management. The integrated architecture provides a direct solution for engineers developing compact and robust power conversion systems, effectively answering the need for a complete power stage in a single, thermally efficient package. Best fit for space-constrained Variable Frequency Drive (VFD) and servo applications up to ~7.5 kW where thermal reliability is a primary design driver.
Key Parameter Overview
Decoding the Specs for Integrated Drive Reliability
The electrical and thermal characteristics of the CM35MX-24A are engineered to provide a robust foundation for motor drive applications. The parameters below have been selected to highlight the module's performance in terms of efficiency, switching capability, and operational ruggedness. Each specification directly contributes to the module's value proposition of simplifying design while enhancing long-term reliability.
| Parameter | Value | Engineering Implication |
|---|---|---|
| Collector-Emitter Voltage (Vces) | 1200V | Provides a substantial safety margin for applications on 400V to 480V AC lines, protecting against voltage transients. |
| Collector Current (Ic) | 35A (Tc = 80°C) | Supports motor applications typically in the 5.5 to 7.5 kW range, depending on switching frequency and cooling efficiency. |
| Collector-Emitter Saturation Voltage (VCE(sat)) | 1.70V (typ) / 2.20V (max) @ Ic=35A, Tj=125°C | Lower VCE(sat) directly reduces conduction losses, minimizing heat generation and improving overall drive efficiency. |
| Isolation Voltage (Viso) | 2500 Vrms (1 min) | Guarantees high electrical isolation between the power circuit and the mounting heatsink, enhancing safety and simplifying assembly. |
| Thermal Resistance (Rth(j-c)Q) | 1.07 °C/W (per IGBT) | Indicates efficient heat transfer from the IGBT junction to the case, a critical factor for effective cooling system design. |
| Short-Circuit Withstand Time (tsc) | ≥ 10µs (Vcc=600V, Vge=15V, Tj=125°C) | Defines the module's robustness, allowing sufficient time for protection circuits to detect a fault and safely shut down the system. |
Download the CM35MX-24A datasheet for detailed specifications and performance curves.
Application Scenarios & Value
System-Level Benefits in Compact Motion Control Systems
The CM35MX-24A is engineered specifically for power conversion systems where space, assembly simplicity, and reliability are paramount. Its highly integrated 7-in-1 design consolidates the entire power stage of a typical motor drive into a single component footprint.
Consider the design of a compact Variable Frequency Drive (VFD) for a materials handling conveyor system. A key engineering challenge is managing heat dissipation within a small, often poorly ventilated, control cabinet. A discrete solution requires separate rectifier diodes, six inverter IGBTs, a brake chopper IGBT, and associated freewheeling diodes, each mounted to a heatsink. This creates a complex thermal map with multiple potential hotspots. The CM35MX-24A fundamentally solves this problem by consolidating all major heat-generating components onto a single, isolated baseplate. This centralizes the thermal load, simplifying the heatsink design and airflow management. Furthermore, the integrated thermistor provides a direct, real-time temperature reading from the module's core, enabling precise over-temperature protection that is far more reliable than an ambient sensor within the cabinet. This prevents catastrophic failure during motor stalls or overload events, significantly increasing the VFD's operational lifespan.
This module is a prime candidate for applications such as:
- Small to medium-power industrial motor drives and VFDs
- Servo drives for factory automation and robotics
- Pump and fan control systems
- Power supplies for commercial and industrial equipment
While the CM35MX-24A is optimized for applications up to 35A, systems requiring higher motor output can consider the related CM50DY-24H, which offers a 50A current rating within a similar integrated topology.
Technical Deep Dive
A Closer Look at the 7-in-1 Topology and Integrated Thermal Sensing
The core innovation of the CM35MX-24A lies in its Converter-Inverter-Brake (CIB) architecture. This topology integrates three distinct power electronics functions into one seamless module. The "Converter" section is a three-phase diode bridge that rectifies the incoming AC line voltage into a DC bus. The "Inverter" section consists of a three-phase bridge of six IGBTs and six freewheeling diodes, which synthesizes a variable voltage, variable frequency AC waveform using Pulse Width Modulation (PWM) to control motor speed and torque. Finally, the "Brake" chopper, an additional IGBT and diode, manages regenerative energy. During motor deceleration, kinetic energy flows back to the DC bus; the brake chopper diverts this excess energy to an external braking resistor, preventing a DC bus overvoltage fault.
The engineering value of this integration extends beyond mere component reduction. The most significant benefit is in thermal management. Think of the integrated thermistor as a built-in fever thermometer for the module's core. In a discrete design, engineers must place external sensors and extrapolate the junction temperatures based on case readings and thermal models. The CM35MX-24A's internal NTC thermistor provides a direct electrical signal that correlates precisely with the substrate temperature. This allows the system's microcontroller to make smarter, faster decisions—reducing current or increasing fan speed—based on actual device conditions, not estimations. This direct feedback loop is fundamental to building a truly robust and reliable drive that can operate safely closer to its thermal limits.
Frequently Asked Questions
Engineering Inquiries on the CM35MX-24A Module
How does the integrated thermistor in the CM35MX-24A enhance system protection?
The built-in NTC thermistor provides a direct and accurate measurement of the module's substrate temperature. This enables the drive's control system to implement precise over-temperature protection (OTP), preventing thermal runaway and enhancing long-term reliability far more effectively than an ambient air sensor.
What is the primary benefit of the module's 7-in-1 (CIB) topology for a design engineer?
The CIB topology drastically reduces design complexity. It minimizes component count, shrinks PCB size, simplifies the bill of materials (BOM), and streamlines the assembly process. It also centralizes the system's primary heat source, simplifying heatsink design and mechanical layout.
The datasheet specifies a VCE(sat) of 1.70V. How does this translate to thermal performance in a VFD?
A lower VCE(sat) means lower power is dissipated as heat during conduction (P_cond = VCE(sat) * Ic). For a VFD, this directly translates to higher energy efficiency and a reduced thermal load on the cooling system, allowing for a smaller heatsink or operation at higher ambient temperatures.
Can the CM35MX-24A's brake chopper be used for dynamic braking applications?
Yes. The integrated brake chopper is specifically designed for dynamic braking. When a motor decelerates, it acts as a generator. The chopper diverts this regenerated energy to an external braking resistor, safely dissipating it as heat and preventing the DC bus voltage from rising to damaging levels.
What are the key considerations for gate drive design for the inverter section of this module?
A proper gate drive circuit should provide the recommended gate-emitter voltage (typically +15V for turn-on, -10V to 0V for turn-off) with sufficient peak current to charge and discharge the IGBT gate capacitance quickly. This ensures efficient switching and minimizes switching losses. Isolation and protection features like desaturation detection are also critical for robust operation.
An Engineer's Perspective
From a design engineering standpoint, the Mitsubishi CM35MX-24A is less a single component and more of a pre-validated subsystem. It abstracts away the complexity of designing, sourcing, and thermally managing three separate power stages. The value is measured in reduced design cycles, simplified assembly lines, and a more predictable thermal profile. For applications where time-to-market and field reliability are critical metrics, the integrated approach offered by this IGBT Module provides a clear and tangible engineering advantage.
