M. Mathew

Oxford Brookes University, Oxford, England, United Kingdom

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Publications (6)2.04 Total impact

  • M. Mathew · B. L. Hart · K. Hayatleh ·
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    ABSTRACT: The theoretical background and a selection of simulated results are presented for a 10 µA PTAT current generator that is a modified CMOS version of an existing bipolar configuration. Using standard 0.35 µm CMOS technology, the circuit exhibits a current variation of less than 0.01% when the supply rail voltage is changed from 0.5 to 10 V.
    International Journal of Electronics 11/2012; 99(11):1-6. DOI:10.1080/00207217.2012.680181 · 0.46 Impact Factor
  • M. Mathew · B. L. Hart · K. Hayatleh · F. J. Lidgey ·
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    ABSTRACT: Operating from a 1 V rail supply, a proposed CMOS current-controlled DC current generator can function as a repeater, attenuator or amplifier over the input current range, 1 µA to 1 mA, with a current-transfer ratio accuracy better than 1% using IBM technology, characterised by a process with a 0.13 µm minimum feature size. In repeater mode, the incremental output resistance exceeds 30 MΩ for an output current of 500 µA at an output voltage of 0.20 V, and exceeds 1 MΩ for an output current of 1 mA at an output voltage of 0.22 V. For zero input current, the circuit dissipation is 117 µW.
    International Journal of Electronics 08/2011; 98(8):1123-1127. DOI:10.1080/00207217.2011.582422 · 0.46 Impact Factor
  • M. Mathew · K. Hayatleh · B. L. Hart ·
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    ABSTRACT: This paper describes the design of a high-transconductance, wide-band, temperature-insensitive bipolar differential voltage-to-current converter, the transconductance of which is determined by a chosen degeneration resistor. Detailed illustrations of current and voltage traces are included to clarify circuit operation. Comparison with previously published designs shows that this converter provides better linearity, with very low temperature sensitivity and excellent transconductance predictability. Simulation results show that the proposed circuit, with a nominal transconductance of 5mS, has a Total Harmonic Distortion (THD) better than −70dB at 10MHz, with a degeneration resistor of 400 Ω over an input voltage range of 350mV for supply voltages of ±2.5V. The analysis and simulation comparisons are in good agreement. KeywordsTransconductance-Voltage-to-current converter-Total harmonic distortion-Global feedback-Emitter degeneration
    Circuits Systems and Signal Processing 12/2010; 29(6):1123-1140. DOI:10.1007/s00034-010-9193-5 · 1.12 Impact Factor
  • M. Mathew · K. Hayatleh · B.L. Hart · F.J. Lidgey ·
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    ABSTRACT: This paper describes a highly linear and low- distortion, bipolar differential voltage-to-current converter (V-I) circuit that can be used for a number of applications, such as the transconductance stage for mixer circuits and gm-c filter circuits. This circuit is capable of providing a wider linear range of operation and lower total harmonic distortion compared with the conventional emitter-degenerated emitter-coupled differential pair due to the global feed-back technique used. Simulation results show that this circuit can provide 30dB improvement in total harmonic distortion over an operating range from -0.5V to +0.5V. This circuit uses a supply voltage of plusmn2.5V and an emitter degeneration resistor of 600 Omega.
    Design and Technology of Integrated Systems in Nanoscale Era, 2008. DTIS 2008. 3rd International Conference on; 04/2008
  • M. Mathew · K. Hayatleh · B.L. Hart · F. Lidgey ·
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    ABSTRACT: This paper considers two schemes in which negative feedback is applied to a conventional emitter-coupled differential voltage-to-current converter circuit in order to achieve lower distortion. Representative circuits for each of these schemes together with simulated results for a given value of emitter-degeneration resistor are presented. It is possible to achieve a reduction in total harmonic distortion (THD) exceeding 20dB, for a peak-to-peak differential input voltage of 500mV, over that possible without this feedback.
    Circuits and Systems, 2007. MWSCAS 2007. 50th Midwest Symposium on; 09/2007
  • M. Mathew · K. Hayatleh · B.L. Hart · F.J. Lidgey ·
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    ABSTRACT: The use of two complementary emitter-followers, in which the collector currents are held effectively constant by feedback action, facilitates the design of a differential voltage- current converter capable of producing lower output signal distortion. The proposed circuit provides an extended linear operating range, and total harmonic distortion (THD) 20 dB better than that compared with an emitter-degenerated long- tailed pair circuit. Simulation results show that the THD is better than -70 dB for differential input signals up to 0.5 V at a test frequency of 1 MHz and supply voltage of plusmn5 V.
    Research in Microelectronics and Electronics Conference, 2007. PRIME 2007. Ph.D.; 08/2007

Publication Stats

5 Citations
2.04 Total Impact Points


  • 2007-2012
    • Oxford Brookes University
      • Department of Computing and Communication Technologies (CCT)
      Oxford, England, United Kingdom