The rise in environmental and safety awareness has led to progress in the digitization and electrification of automobiles including motorcycles, increasing the number of ECUs mounted. More ECUs are mounted in the vicinity of heat generating parts such as engines, increasing the demand for heat resistance of protective devices against load dump surges.
Panasonic successfully developed and commercialized the world's first ZnO varistor (zinc oxide varistor) in 1968. By utilizing the varistor technology it developed over the years since, the company has commercialized ZNR high energy varistors suitable for a wider range of automotive applications, as part of its efforts to improve the heat resistance of varistors for load dump surge protection.
- Their unique structure achieves both bending strength and the industry's highest level of heat resistance temperature of 150°C.
- Excellent product characteristics (resistance performance against load dump surges, clamping voltage) protect automotive ECUs from surges.
- The reduced size and weight save space and lower environmental load.
1. Their unique structure achieves both bending strength and the industry's highest level of heat resistance temperature of 150°C.
With an increase in the number of ECUs mounted in the vicinity of heat generating parts such as engines, automotive applications now require varistors with a higher heat resistance. However, as single components, conventional varistors are susceptible to rapid heat stress due to temperature changes although their resin mold structure makes them resistant to the deflection stress of the board. This necessitated the restriction of their operating temperature range to -40°C to 125°C. By applying its material and structure design technologies accumulated through the development of various high heat-resistance devices, Panasonic has significantly reduced stress due to temperature changes, achieving the industry's highest operating temperature range of -55°C to 150°C (Panasonic's previous product: -40°C to 125°C).
Appearance / structure
new material composition
2. Excellent product characteristics (resistance performance against load dump surges, clamping voltage) protect automotive ECUs from surges.
The newly developed varistors provide excellent protection performance for automotive ECUs against surges due to their resistance performance against load dump surges that complies with the international standard ISO16750-2 and JASO D 001-94 Type A A-1 related to automotive load dump surges, as well as by achieving the industry's lowest* clamping voltage of 35 V max.
* As ZnO varistor products (as of March 25, 2022, Panasonic data)
Characteristics of products ISO16750-2 test (P/N：ERZHF2M220F)
Characteristics of products JASO A-1 test (P/N：ERZHF2M220F)
3. The reduced size and weight save space and lower environmental load.
The newly developed varistors are compact with dimensions of 6.4 mm (W) × 8.0 mm (L) × 5.5 mm (H), enabling the reduction of the mounting area and weight to a half or less compared to Zener diodes with equivalent performance, thereby contributing to the reduction of the amount of environmentally hazardous substances used.
Various usage in ECU
|Varistor voltage||20 ~ 23.2V|
|Maximum allowable voltage||DC 16V|
|Short time overvoltage||24 VDC -5 min.|
|Clamping voltage||35V max.|
|Resistance performance against load dump surges||JASO D 001-94 A A-1, 70 V, once|
|Load dump surge energy
ISO16750-2 TEST A
|50J max. 10 times|