International Journal of Electrical and Electronics Engineering Research (IJEEER) ISSN 2250-155X Vol. 3, Issue 2, Jun 2013, 147-152 © TJPRC Pvt. Ltd. DESIGN OF HIGH-SPEED MULTI BIT LOGIC DECODER FOR CURRENT MODE SWITCHING PRASHANT SINGH 1 & NARENDRA BAHADUR SINGH 2 1 Senior Project Fellow at CSIR-CEERI, Pilani, India 2 Chief Scientist, MEMS, MS & RF ICS Design, Central Electronics Engineering Research Institute (CSIR-CEERI), Pilani, India ABSTRACT Circuit Design for high-speed multi bit logic decoder for input current mode switching has been presented in this paper, Its functionality has been verified for 180nm TSMC CMOS foundry‟s parameters for eldo spice level 53 on Mentor Graphics and tspice level 49 on TANNER EDA platforms. Similarly, its functionality has been also verified for 1.2μm SCL Chandigarh CMOS Technology model parameters on both design platforms. Maximum pulse mode operation‟s speed of the circuit for 180nm TSMC foundry is 1GHz and 20MHz for 1.2μm SCL Foundry. It uses minimum circuit elements with respect to other similar circuit‟s functionality, low power consumption and faster conversion time to decode logic from the input current. KEYWORDS: CMOS Analogue Circuits, Multi Valued Logic, Binary Logic, Encoder and Decoder Digital Circuit INTRODUCTION As per prior art, such components are very much useful in semiconductor memories, like current sensing in memory. Researchers were worked on current mode cmos multi valued logic decode using sense amplifier, current mode quaternary threshold logic full adders, current mode analog to quaternary converter, current to voltage converter, etc. The beauty of such circuit is faster speed with minimum circuit elements to implement such type of functionality. THEORY The presented work relates to high-speed multi bit logic decoder‟s design for current mode switching. CMOS transistors‟ circuit has been designed to decode the logic based on input current to the circuit. The purpose of this circuit is to generate logic on the basis of input current to the circuit, therefore if the current generation is based on logic pattern then further to decode the logic from the current, such circuits could be used. It would be applicable in efficient flash memories logic decoder or similar other decoders, as well as current sensing devices. Here, the quantizer module, as shown in Figure 1, composed of multi valued logic circuit based on input current amplitude and it generates the outputs correspond to multi valued logic level which goes to the encoder assembly through the inverter [1-5], to produce the logical pattern needed by the logic decoder assembly [8-10], to generate the binary outputs on the basis of instantaneous input current magnitude. The circuit is designed completely either on mos transistor basis or resistance at input with mos transistors. Circuit idea has been verified by the semiconductor industry grade circuit design tools using device grade foundry‟s Hspice model parameters for 1.2μm SCL and 180nm TSMC CMOS Technology data. Circuit performance is superior on the basis of lower power consumption and faster speed due to purely logic function and minimum circuit elements with respect to other similar circuit‟s functionality. Logic voltage level „1‟ depends on the technology, in case for TSMC 180nm technology, it is 1.8V and 5V in SCL 1.2 μm Technology, the input current is in mAmp range, its magnitude also depends on technology.