A Digitally Programmable Highly Linear Active-RC Filter by Hussain Alzaher Electrical Engineering Department King Fahd University of Petroleum & Minerals Dhahran, Saudi Arabia

2 Outline  Introduction Motivation Objectives  Tuning Element  Proposed Integrator Integrator design Non-ideal analysis  Low Power Opamp  Proposed Filter  Experimental Results  Conclusion

3 INTRODUCTION  Active-RC exhibits high dynamic range.  Lack of efficient programmability feature. MOSFET-C  MOSFET-C suffers from poor linearity.  Tuning range limited for low supply voltages. Capacitor/Resistor Arrays  Occupy relatively large area.  Switching transistors degrade linearity. Motivation

4 INTRODUCTION  Provide efficient solution to the tuning problem.  Maintain high linearity.  Tuning circuit should not degrade the performance of the overall design. Objectives

5 Tuning Element Current Division Network (CDN)  Inherently linear.  Switching transistors are part of the original circuit.  Suitable for low power operation.

6 Proposed Integrator

7 Non-Ideal Effects Parasitic pole at Miller integrator exhibits a parasitic pole at and The proposed integrator exhibits higher parasitic pole and better Q I

8 Low Power Opamp

9 Proposed Filter

10 Proposed Filter   o can be tuned without disturbing Q and H o.  H o and Q o can be implemented precisely in ICs as they are functions of resistor and/or capacitor ratios.

11 Experimental Results  Fully balanced 4th-order lowpass filter for a zero-IF Bluetooth receiver is designed.  TSMC CMOS 0.18 m m (MOSIS)  Supply Voltage ±1. 5V.  Total Supply Current 1mA.  6-bit CDN used for tuning.  Corner frequency 600kHz.

12 Experimental Results

13 Experimental Results Proposed Filter Specifications

14 Conclusion  xxxxxx

15 THANK YOU