Safely dissipating voltage spikes
Measurement specialist Isabellenhütte introduces an innovative series of pulse load resistors designed to absorb voltage spikes in power electronics used in automotive applications. These resistors protect downstream components from damage caused by electrical overstress. The PMx series features a flat, space-saving design, high pulse load capacity, rapid heat dissipation, and efficient SMD mounting.
Voltage spikes can be triggered by fast switching operations and amplified by inductances, potentially damaging or destroying downstream components. The new PMx pulse load resistors from Isabellenhütte—starting with the PMT (2817) size—safely dissipate these peaks. Based on Isabellenhütte’s proven SMD shunt technology, the PMx series is not intended for precision measurement but for damping voltage spikes.
ISA-PLAN® Design for High Pulse Load Capacity and Array Configuration
The PMT design follows the ISA-PLAN® principle: a copper substrate carries a foil made of Isabellenhütte’s proprietary Noventin® resistive material. Its high specific resistance enhances pulse load capacity. Voltage peaks are temporarily stored in the resistive material and dissipated as heat through large copper terminals into the PCB.
Depending on the pulse energy, one or more resistors may be required. Multiple resistors can be configured in parallel or series arrays to evenly distribute the load. The number and configuration depend on expected pulse loads, available PCB space, and desired resistance values.
Application Example: Snubber Resistor for E-Fuse
In a snubber circuit consisting of a resistor and capacitor, PMx resistors are ideal for use in E-Fuses—resettable electronic fuses found in power supply for a car´s cigarette lighter. When excessive current is drawn, the E-Fuse disconnects to protect connected devices. The rapid disconnection activates the snubber circuit. The capacitor initially absorbs the pulse load and discharges through the pulse load resistor, which converts the energy into heat and dissipates it via copper terminals into the PCB.
Reliability according to automotive standards
All resistors in the PMx series are tested in accordance with the AEC-Q200 automotive standard. Within this series, the PMT is currently available in size 2817 with a value range from 50 mOhm to 2.5 Ohm (R050, R500, 1R00, and 2R50). The PMT is currently in the final phase of the qualification process, with series production (SOP) scheduled to start at the end of March 2026. In addition to the values listed in the data sheet, customer-specific variants can also be realized within this range. Furthermore, other sizes are available on request: The feasibility of the PMS in 2512 has already been tested and can be implemented at short notice, as existing equipment from measurement shunt production can be used. The PMP in size 2010 is also available as an additional option. Samples are available on request.
Technical Support from Isabellenhütte
PMx pulse load resistors are easy to integrate into PCB designs. For higher pulse loads, Isabellenhütte offers support in selecting the appropriate number and type of resistors, as well as in dimensioning, configuration, and design-in. Upon request, thermal simulations can be performed to assess heat development and dissipation.
Key Benefits of PMx Pulse Load Resistors:
About Isabellenhütte Heusler
Isabellenhütte Heusler GmbH & Co. KG has been family-owned since 1827. Today, it is one of the leading manufacturers of precision and power resistors as well as precision alloys. Another business segment is the development of measurement technology products. The company employs around 1,000 people at its headquarters and production site in Dillenburg, Hesse.
www.isabellenhuette.com
Image 1 – Array Configuration: Depending on expected pulse load, available PCB space, and desired resistance values, multiple pulse load resistors can be connected in parallel and/or series to evenly absorb voltage spikes. Image: © Isabellenhütte Heusler GmbH & Co. KG
Image 2 – As part of a snubber circuit (resistor + capacitor), the pulse load resistor works with the capacitor to eliminate voltage spikes. The capacitor absorbs the pulse load and discharges through the resistor, which converts the energy into heat and dissipates it via copper legs into the PCB. Image: © Isabellenhütte Heusler GmbH & Co. KG
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Michaela Wassenberg
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Industry and Technology GmbH
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Benjamin Baldauf
Director Marketing
Corporate Marketing
Isabellenhütte Heusler GmbH & Co. KG
Eibacher Weg 3–5
D-35683 Dillenburg
Phone: +49 2771 / 934-789
Email: benjamin.baldauf@isabellenhuette.com