ROHM Developed the "ESR01" Series of Anti-Surge Chip Resistors


ROHM Co., Ltd. (Kyoto-based) recently developed the "ESR01" Series of anti-surge chip resistors for a wide range of applications from mobile devices such as phones to various power supply devices. ROHM has already unveiled samples of the "ESR01" resistors (at a sample price of 3 yen/piece), and launched mass-production in July on a monthly production scale of 5 million pieces at its production base, ROHM Integrated Systems (Thailand) Co., Ltd. (Thailand-based).

In recent years, as electronic devices in general have become smaller and more sophisticated, there has been growing demand for compact, high-power resistors. Using ROHM's high-precision processing, printing, and trimming technologies acquired from the development of ultra-compact chip resistors (0402 size), the company has now developed anti-surge chip resistors that achieve a high power of 0.2W in the 1005 size for the first time in the world. Compared to the ROHM's conventional products (0.063W) of the same size, the "ESR01" series of anti-surge chip resistors provides about 3.2 times more rated power and makes it possible to substantially reduce the mounting area (by about 60%). In addition, as the internal configurations of electronic devices are becoming increasingly complex, the need for surge protection is further heightening. Since surge voltage can destroy the circuit itself, taking preventive measures against surge voltage has become essential to designing electronic circuits. Consequently, the use of anti-surge chip resistors that provide high power and enhanced anti-surge characteristics has been increasing each year. Under these circumstances, conventional anti-surge chip resistors were available just for the minimum package of 1608 size. ROHM optimized the resistive element patterns and reexamined the materials used in the elements, eventually achieving 2kV ESD resistance with compact 1005-size chip resistors (HBM). For example, high-voltage chip resistors of the 1608 size have so far been used in strobe flash circuits of cell phones because an instantaneous high voltage is applied to the circuits. In contrast, since the "ESR01" chip resistors have enhanced anti-surge characteristics, these resistors make it possible to replace earlier configurations with the 1005 size, contributing to the miniaturization of strobe flash circuits.

ROHM is leading the world in extensive technologies required for resistors, including compact, high power, and low resistance resistors. Going forward, ROHM will work to expand the lineup of highly reliable resistors for mobile and automotive devices.

Anti-Surge Chip Resistors "ESR01"Series (PDF:437KB)

■Features of "ESR01" Series of Anti-Surge Chip Resistors

  • The World's First high 0.2W rated power achieved in a 1005 size
  • Guaranteed 2kV anti-surge characteristics (HBM)
  • Enhanced pulse characteristics


Type Size(mm) (Rated Power) Resistance
ESR01 1.0×0.5 0.2W 10Ω to 1MΩ J(±5%)
-55 to 155


  • Surge voltage (HBM stands for Human Body Model)
    A voltage generated in electrical circuits, etc. that instantaneously exceeds the steady state.

■Rated Power

Size ESR Series MCR Series
1005 0.2W 0.063W
1608 0.2W 0.1W
2012 0.25W 0.125W
3216 0.33W 0.25W
3225 0.5W 0.25W
5025 - 0.5W

■Anti-surge Characteristics

Anti-Surge Chip Resistor (ESR Series) vs. General-Purpose Chip Resistor (MCR Series)