New Class-Leading 0603-Size(mm) 100mΩ Chip Resistors for Current Detection -Contributes to greater miniaturization and energy savings in smartphones and wearable devices-

ROHM has recently announced the development of low-ohmic chip resistors optimized for current detection applications in compact equipment such as smartphones and wearable devices.

The UCR006 series of ultra-compact (0.6x0.3mm / 0.2 x0.1inch) thick-film chip resistors is offered in resistances as low as 100mΩ, providing greater energy savings. They are also the first 0603-size(mm) / 0201-size(inch) resistors in the industry to ensure a temperature range of -55 to 155°C in the low-ohmic region, and feature twice the rated power compared with competitor products in the same size, enabling support for a wide range of applications. This higher power handling capability in a smaller size makes them ideal replacements for larger 1005-size(mm) / 0402-size(inch) resistors, contributing to further miniaturization.

In order to operate smartphones and other electronic devices it is necessary to control the voltage and detect current internally, and resistances exceeding 100mΩ are typically used. But to minimize power loss during current detection it is important to use the smallest resistance value possible – while also providing sufficient power rating to ensure reliable performance.

To meet these needs ROHM has developed the UCR series of low-ohmic chip resistors designed for current detection. However, in recent years the proliferation of smartphones and emergence of wearable tech devices have increased the demand for components that are even more compact and consume less power. But in the case of resistors for current detection applications, a number of challenges must first be overcome in order to decrease chip size, such as maintaining low resistance values and tolerances while improving rated power.

ROHM’s latest series utilizes new materials and a new structure to achieve class-leading low resistance (100mΩ) in a 0603-size(mm), thick-film design.

In addition, heat dissipation is improved, and rated power is increased to 0.1W – twice that of conventional products. Operating temperature range has also been expanded in the low-ohmic region to an industry-best -55°C to 155°C, enabling compatibility with a greater variety of applications. And unique laser trimming technology makes it possible to achieve a resistance tolerance of ±1% (F Class), which has been traditionally difficult to realize at low resistances. Furthermore, these new products have adopted the reverse-mount design utilized in the existing series in order to minimize resistance variations during soldering and ensure a temperature coefficient of resistance (TCR) between 0 and 300ppm/°C, which reduces resistance fluctuations due to temperature changes. This provides high accuracy current detection required by today’s high-performance devices. Going forward ROHM will continue to expand its lineup of compact, high accuracy resistors.

Primary Features

1. Ultra-low ohmic thick-film resistors contribute to greater energy savings
New materials and structural design make it possible to achieve 100mΩ in the 0603-size(mm), meeting market needs for lower power consumption components.

2. Wide operating temperature range (-55 to 155°C) expands application compatibility
The expanded operating temperature range enables support for not only portable devices such as smartphones and wearable tech devices, but sets exposed to high temperature environments as well, providing unmatched compatibility.

3. Delivers twice the rated power vs. same-sized products, making them ideal replacements
Utilizing new materials and design structure improves heat dissipation characteristics, enabling a rated power of 0.1W, twice that of equivalent-sized products. This reduces mounting area by 64% over conventional 1005-size(mm) 0.1W types, allowing smaller resistors to be used, contributing to end-product miniaturization.

4. 3 key characteristics provide superior current detection accuracy
1) 1% resistance tolerance (F Class)
Proprietary trimming technology results in ultra-low resistance tolerance (difficult to achieve in the low ohmic region).

2) Excellent temperature coefficient of resistance (TCR)
The rear-mount design ensures a TCR between 0 and 300ppm/°C providing stable, reliable performance over a wide range of temperatures.

3) Resistance fluctuations during soldering minimized
Adopting a rear-mount design prevents possible resistance fluctuations that can occur while mounting.

Applications
- Smartphones
- Wearable devices
- Other compact portable equipment
- HDD/DVD players
- Portable audio

Pricing: $0.2 (per sample)

Availability: Now (samples and OEM quantities)

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Terminology

Rated Power:
Refers to the maximum power consumption that still guarantees safe operation in passives, ICs, and other electronic components. The greater the rated power the less susceptible the product is against thermal changes and accidental voltage/current fluctuations and the better suited it is for higher power environments.

Power Loss:
Resistors, which are capable of detecting current and controlling voltage, convert some of the power applied (voltage, current) to heat. This heat is considered loss. Using incorrect or improper resistances may lead to excessive power loss.

Temperature Coefficient of Resistance (TCR):
The internal resistance of almost any substance will change depending on the temperature. This applies to resistors as well, and the rate of change is referred to as the temperature coefficient of resistance, measured in units of ppm/°C.