Analog organic electronic ADC on flexible foil (ISSCC2010)

At today's International Solid State Circuit Conference (ISSCC), Holst Centre, imec, TNO and KULeuven present an analog-to-digital converter (ADC) designed, fabricated and measured in an organic technology on plastic foil. The result is of great scientific value as it represents the first steps of creating analog organic electronics.

Organic electronics are expected to create new applications and possibilities in the electronics market by introducing flexible displays, low-cost RFID tags etc. But because of the maturity of the technology, the possibilities to create fully-organic circuits are still limited. Using p-type only transistors, digital circuits have been shown by several groups. Analog components are however much more difficult to make, and as a result, progress has been slow.

For the first time, Holst Centre, an initiative by imec and TNO, now reports an organic ADC. The ADC is an important building block in the realization of wireless sensors on thin, flexible foil, such as for instance intelligent food packages and smart bandage applications that are currently under research in the Holst Centre program on Systems-in-Foil.

The ADC is based on a Sigma Delta (??) topology, because of its insensitivity to variations in threshold voltage (Vt). The latter is needed to drive active matrix displays developed by the rollable display company Polymer Vision, from which the underlying organic thin-film-transistor (OTFT) technology was used. An overview of the specifications and measurement results (obtained in an N2 atmosphere at room temperature) can be found in the table below.

Minimal width

25?m

Minimal length

5?m

Typical intrinsic gain

5

fT for minimal transistor

20kHz

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