Chip-type Electric Double Layer Capacitor,"CPX" series come to the market
It is ideal for Energy-Harvesting and Wireless Sensor Network

Seiko Instruments Inc. (SII) proudly introduces new Chip-type Electric Double Layer capacitor, “CPX3225A” as electrical storage device and power source device to the growing market of energy-harvesting, Near Field Communication (NFC) chip, and wireless sensor network systems, etc. The “CPX” series successfully reduced the internal resistance to one-third of the conventional EDLCs, and the leak current to approximately one-tenth, while keeping the world’s thinnest and smallest class size. Mass production is scheduled to start in July 2012.

Electric Double Layer Capacitors (EDLC) function as rechargeable electrical storage devices, and are commonly used for mobile phones, digital still cameras and other battery operated devices. However, conventional small size EDLCs have internal resistance of more than 100 Ohms. The high internal resistance causes output voltage drop when the discharge current is higher than several mAs. As a result, applications of the EDLC were limited to power backup of real time clock (RTC), or SRAM that consume only several micro Amperes or several tens of micro Amperes.

The new “CPX” series have the industry’s lowest internal resistance of 25 Ohms, which is one-third the conventional chip type EDLCs, while keeping its size to the world smallest-class size (3.2 x 2.5 x 0.9mm) yet with large capacity (2.5 – 7.5mF).

Due to this lower internal resistance, higher discharge current, from several mAs to tens of mAs (several mW to 100 mW) has become possible, and super rapid charging within several seconds is also realized. In addition, by reducing leak current (self-discharge) to 10 nA level, which is approximately one-tenth that of the conventional capacitors, the “CPX” series can be charged sufficiently by several micro Watts of slight electromotive force from energy harvesting devices. Furthermore, a superior air-tight ceramic package assures its long term reliability.


1. Large discharge current and super rapid charging achieved by low internal resistance

Reduced internal resistance to 25 ohms, one-third that of the conventional EDLCs, allows discharge current of up to several tens of mAs, and rapid charging within a few seconds.

2. Chargeable by slight power, thanks to low leak current

Reduced leak current to about 10 nA level, approximately one-tenth that of the conventional EDLCs, allows sufficient charging with several micro Watts of slight energy harvesting power source.

3. Long life span, high reliability

Superior air-tight ceramic package reduces storage deterioration in high temperature and high humidity environments, and assures long term reliability.

4. Small size, large capacity

Two types of capacitance, 2.5mF and 7.5 mF are included in the lineup. A higher capacitance is realized, although the sizes are still kept at the world smallest class size (3.2 x 2.5 x 0.9mm).


Part number Maximum UseVoltage


Internal Resistance(Typical) Size (LxWxH) Weight (g)
CPX3225A252D 2.6V 2.5mF 25Ω 3.2×2.5×0.9mm 0.024g
CPX3225A752D 2.6V 7.5mF 25Ω 3.2×2.5×0.9mm 0.024g

Application Examples

1. Electric storage device for energy harvesting
2. Power source or Electric storage for Wireless Sensor Network, RFID tag, RF remote control for digital home electrical appliance
3. Power source or Electric storage for Contactless IC card, multi-functional IC card
4. Instant back-up for CPU or DRAM and powers source for saving data on flash memory

Sample release and mass production schedule

Sample: April, 2012 Mass Production: End of July, 2012

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