A 72- W 90-dB Wide-Range Potentiostatic CMOS Modulator with Flicker - PowerPoint PPT Presentation

72- W 90-dB Wide-Range Potentiostatic Modulator 1/22 A 72- W 90-dB Wide-Range Potentiostatic CMOS Modulator with Flicker Noise Cancellation for Smart Electrochemical Sensors J. Aymerich 1 , M. Dei 1 , L. Terés 1,2 , F. Serra-Graells 1,2 1 Instituto de Microelectrónica de Barcelona, IMB-CNM(CSIC), Spain 2 Universitat Autònoma de Barcelona, Spain joan.aymerich@imb-cnm.csic.es May 2019 J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 2/22 Sensors Maket Vision Several organizations created visions for continued growth to trillion(s) sensors $15 trillion by 2022 r Electrochemical sensors are growing a e y / Sensors/year % exponentially due to potential of 6 5 miniaturization and mass production 21%/year Monolithic or hybrid integration 222%/year onto CMOS platforms Applications in biosensors, quality control, health care, ... Year Expected sensor production growth per year www.eenewsanalog.com J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 3/22 1 Amperometric Electrochemical Sensors 2 Potentiostatic Modulator architecture 3 Proposed wide-range potentiostat with 1/f noise cancellation 4 0.18- CMOS Design and Post-Layout simulations 5 Conclusions J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 3/22 1 Amperometric Electrochemical Sensors 2 Potentiostatic Modulator architecture 3 Proposed wide-range potentiostat with 1/f noise cancellation 4 0.18- CMOS Design and Post-Layout simulations 5 Conclusions J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 4/22 Amperometric Electrochemical Sensors Interaction with microorganisms Interaction with microorganisms. Selectivity by functionalization. Reduced speed and life time. Potentiostatic and amperometric operations. Three electrodes: Measurement independent of the R and C impedances. Linear model Current associated to the electrons involved in a redox process: Electrochemical time constant: J. Aymerich Gubern

6/22 72- W 90-dB Wide-Range Potentiostatic Modulator Classic circuit implementation Potentiostat A 1 establishes the control loop to accomplish potentiostat operation. & Amperometry A 2 converts sensor current to voltage for digitization and readout. Requires multiples OpAmps + ADC. Large area and power consumption. J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 7/22 1 Amperometric Electrochemical Sensors 2 Potentiostatic Modulator architecture 3 Proposed wide-range potentiostat with 1/f noise cancellation 4 0.18- CMOS Design and Post-Layout simulations 5 Conclusions J. Aymerich Gubern

8/22 72- W 90-dB Wide-Range Potentiostatic Modulator 1 st order Potentiostatic Sensor-on-the-loop Behaviour similar to low-pass fi rst-order S/H single-bit CT A/D modulator. Error current converted into voltage and shaped in frequency by the electrochemical sensor itself. High OSR easly obtained with kHz-range Feedback DAC clock frequencies. Amperometric read-out through the output by chemical input . Linear model J. Aymerich Gubern

9/22 72- W 90-dB Wide-Range Potentiostatic Modulator 1 st order Potentiostatic Typical tonal component of 1 st order S/H Limited potentiostatic range programmability (Vrw): Vpot only applies to the Reference Electrode (R). DAC fl icker noise not shaped by loop. Feedback DAC Noise fl oor in the signal band (BW < 1Hz) dominated by fl icker noise. J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 10/22 1 Amperometric Electrochemical Sensors 2 Potentiostatic Modulator architecture 3 Proposed wide-range potentiostat with 1/f noise cancellation 4 0.18- CMOS Design and Post-Layout simulations 5 Conclusions J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 11/22 From 1 st to 2 nd order Second-order noise shaper Quantizer From electrochemical only to hybrid/mixed S/H electrochemical/electronic Tones and pattern noise suppression. Feedforward path Feedback DAC J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 11/22 From 1 st to 2 nd order Second-order noise shaper Quantizer From electrochemical only to hybrid/mixed S/H electrochemical/electronic Tones and pattern noise suppression. Feedforward path Small-signal model Feedback DAC 2 nd order requires stability compensation Feedforward path LHP Zero through feedforward path J. Aymerich Gubern

12/22 72- W 90-dB Wide-Range Potentiostatic Modulator Wide-range potentiostatic 2 nd order Programmable-WE through Gm 1 : Extend potentiostatic range virtually up to double the supply voltage: Feedback DAC J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 12/22 Wide-range potentiostatic 2 nd order Programmable-WE through Gm 1 : Extend potentiostatic range virtually up to double the supply voltage: Small-signal model Feedback DAC Loop stability: High power consumption on Gm 1 to push RHP zero to high frequencies: J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 13/22 Di ff erential DAC wide-range potentiostatic 2 nd order Programmable-WE through Gm 1 : Extend potentiostatic range virtually up to double the supply voltage Feedback DAC J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 13/22 Di ff erential DAC wide-range potentiostatic 2 nd order Programmable-WE through Gm 1 : Extend potentiostatic range virtually up to double the supply voltage Small-signal model Feedback DAC Loop stability: RHP self-canceled both Ifsp,n are used in both quantization symbols. Gm1 only has to cope with Ifsp,n mismatching. J. Aymerich Gubern

14/22 72- W 90-dB Wide-Range Potentiostatic Modulator Flicker Noise Cancellation Gm 1 OTA switching. I fsp,n noise currents are always bypassed to Gm 1 OTA or biphasically integrated into Vrw. Feedback DAC J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 14/22 Flicker Noise Cancellation Gm 1 OTA switching. I fsp,n noise currents are always bypassed to Gm 1 OTA or biphasically integrated into Vrw. qmod = 0 Feedback DAC Feedback DAC J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 14/22 Flicker Noise Cancellation Gm 1 OTA switching. I fsp,n noise currents are always bypassed to Gm 1 OTA or biphasically integrated into Vrw. qmod = 0 Feedback DAC Feedback DAC J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 14/22 Flicker Noise Cancellation Gm 1 OTA switching. I fsp,n noise currents are always bypassed to Gm 1 OTA or biphasically integrated into Vrw. Feedback DAC qmod = 0 qmod = 1 Feedback DAC Feedback DAC J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 14/22 Flicker Noise Cancellation Gm 1 OTA switching. I fsp,n noise currents are always bypassed to Gm 1 OTA or biphasically integrated into Vrw. Feedback DAC qmod = 0 qmod = 1 Feedback DAC Feedback DAC J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 14/22 Flicker Noise Cancellation Gm 1 OTA switching. I fsp,n noise currents are always bypassed to Gm 1 OTA or biphasically integrated into Vrw. Feedback DAC qmod = 0 qmod = 1 Feedback DAC Feedback DAC J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 14/22 Flicker Noise Cancellation Optimum cancellation when qmod has equal probability of 1's and 0's quant. symbols (case of very weak chemical signals ). qmod = 0 qmod = 1 Feedback DAC Feedback DAC J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 15/22 1 Amperometric Electrochemical Sensors 2 Potentiostatic Modulator architecture 3 Proposed wide-range potentiostat with 1/f noise cancellation 4 0.18- CMOS Design and Post-Layout simulations 5 Conclusions J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 18/22 Electrochemical sensor frontend CMOS layout 0.18 μ m 1P6M CMOS X-FAB technology (XH018). 480 μ m x 370 μ m ( 0.18mm 2 ). On-Chip auxiliary modules. I 2 C 4-wire bus interface. 1.8-V capless LDO core supply regulator. Current generator. Vpotp,n programmable sources. J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 19/22 Post-Layout Simulations 3-Vpp cyclic voltammetry example under 1.8-V voltage supply. VerilogA: Vrw-Isens DC look-up table based on a Cyclic Voltammetry. Third order Butterworth low-pass fi lter as digital decimator. 2.5-Hz cutt-o ff freq. VerilogA. J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator Post-Layout Simulations Output spectrum comparison w/ (a) and w/o (b) fl icker cancelation technique. Weak input signal -65dB FS ±100-nA full scale. Oversampling ratio 128: Sampling freq. 256Hz (b) Bandwidth 1Hz (a) J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 21/22 Performance simulation results J. Aymerich Gubern

72- W 90-dB Wide-Range Potentiostatic Modulator 1 Amperometric Electrochemical Sensors 2 Potentiostatic Modulator architecture 3 Proposed wide-range potentiostat with 1/f noise cancellation 4 0.18- CMOS Design and Post-Layout simulations 5 Conclusions J. Aymerich Gubern