Ultra Low Power Analog Integrated Circuits for Implantable Medical Devices

Ultra Low Power Analog Integrated Circuits for Implantable Medical Devices Fernando Silveira Universidad de la República, Uruguay CCC Medical Devices nanowattics F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 1

Objectives of this talk Introduce the needs and characteristics of Active Implantable Medical Devices (AIMDs) from the circuit designer point of view. Present the techniques and circuits applied in Analog ULP Device Modeling Design Methodology Circuit techniques Show the current research and development topics and prospects of the area F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 2

Engineering School Universidad de la Republica Founded 1888, approx. 1k new students / year, 670 teaching staff F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 3

Microelectronics Group Since 1991 Under Graduate & Graduate Teaching (MSc, PhD) Research Design of Analog / RF and Mixed-Signal Integrated Circuits, particularly Ultra-Low Power (ULP) Also works on ULP Digital / DC-DC and Embedded Strong links with Research groups abroad Industrial Experience Implantable Medical Devices 2007: spin-off: NanoWattICs F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 4

Implantable Devices in Uruguay Feb. 3, 1960: Drs. O. Fiandra and R. Rubio performed the first effective pacemaker implant to a human being in the world. 1969: Dr. O. Fiandra founded CCC to develop and manufacture pacemakers 1999: CCC develops a pacemaker line based on an DDDR ASIC designed by the Microelectronics Group of Universidad de la Republica Today: CCC designs and manufactures active implantable devices and complete medical systems for third parties. F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 5

Outline I. System: Active Implantable Medical Devices Today II. Transistors and Circuits: Analog Design for ULP. Transistor Modeling. Design Methodology. III. Circuit Techniques: Implementation of AIMDs blocks IV. Conclusions and Prospects F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 6

Active Implantable Medical Devices (AIMD) Implantable: Introduced inside the body by a medical procedure and intended to remain there after the procedure. Active: Including a Power Source Not considered here: Passive implants (e.g. bone prostheses, valves, stents) Wearable / Portable / Swallowable (!) Active Medical Devices F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 7

AIMDs: Main Historical Milestones (I) Cardiac Pacemaker: first implantable device, 1960 Cochlear Implants (1960s -) F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 8

AIMDs: Main Historical Milestones (II) Cardiac Defibrillators (1980) Deep Brain Stimulator for Parkinson (1995) F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 9

AIMDs: Some of the new developments Heart Failure Obesity Diabetes Neurostimulators: Pain control Blood pressure control Foot drop correction Urinary incontinence Sleep Apnea Patient monitoring Brain computer interface F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 10

Pacemaker: Goal: Treat Bradycardia (slow heart rythm) and conduction disorders between atria and ventricles How: Stimulating to contract the heart when it does not contract spontaneously ( watchdog ) Sensing of: Some system examples cardiac muscle signals that indicate ventricles / atria contraction other indicators of physical activity, additionally in some cases F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 11

Stimulation (Open Loop) Early Pacemakers Cochlear Implants Deep Brain Stimulators for Parkinson Neurostimulators (sometimes Man/Woman in the loop ) Stimulation and Sensing (Closed Loop) Cardiac area (Pacemakers, Defibrillators, Heart Failure) Obesity Some Neurostimulators Only Sensing Basic Functions Implanted long term Holter ( insertable loop recorder ) Sensing + external actuation: Brain-computer interface F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 12

Stimulation: Voltage mode E.g.: Pacemakers 0.1V 7.5V 50ms 1.5ms Requires battery voltage multiplier. RL: 500 Ohms typ. F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 13

Stimulation: Current mode t Neurostimulators and others 0.1mA 10mA 30ms 300ms Load voltages up to 15V => Requires battery voltage multiplier F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 14

Sensing: Medical signals in general Low frequency: from < 1 Hz to a few khz (neural signals) Low amplitude: mv to mv Variability: " Most measured quantities vary with time, even when all controllable factors are fixed. Many medical measurements vary widely among normal patients, even when conditions are similar (Source:J. Webster, Medical Instrumentation. Application and Design). Objective of most analog signal processing: qualitative detection for closed loop control. Traditionally advantage to analog implementation in terms of consumption, process scaling is changing this F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 15

Sensing Biopotentials: mioelectric signals (mvs, 100s Hz - 1kHz) cardiac signals (mvs, 10s Hz 300Hz) neural signals (mvs, up to 8kHz) Impedance (tens of mohms => mvs, few Hz) Movement (Physical activity, position) => accelerometer (mvs (sensor dependent), up to 10Hz) F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 16

Auxiliary Functions Telemetry Inductive (up to 10cms) 403 MHz MedRadio Band (a couple of meters) Battery Supervision (Voltage / Impedance / Consumed Charge Measurement) Lead Impedance Measurement Magnet Sensor (Reed Relay / Hall Sensor) Battery Recharge (if applicable) Control: Microcontroller & Firmware F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 17

Non-implantable System Components Medical System Components IPG Leads Patient wand Programmer System Logger PSA Battery charger F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 18

Example: Implantable Pacemakers Approx. Consumption Distribution Programmable Voltage Multiplier 0.1V DD a 2-3 V DD Stimulus Telemetry 35% / 6mA Lead Selection (polarity) Micro controller 30% / 5mA Activity Sensing 18% / 3mA Amplification, Filtering and Detection Sense Channel 17% / 2.8mA Battery Supervision F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 19

Example: Closed Loop Stimulator for Drop Foot Correction (I) Neurostep System (Simon Fraser Univ, Canada, Neurostream Technologies) Closed loop operation based on neural signal sensing and neural stimulation On clinical trials F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 20

Example: Closed Loop Stimulator for Drop Foot Correction (II) http://www.youtube.com/watch?v=xh2vnu2bbnu F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 21

General Requirements: Size Biotronik 1968-1998 (Source: M. Wilkinson, course: MST for Medical Devices) Currently approximately 12 cc (5cm x 4cm x 0.6cm) Approx. 30 to 40% occupied by the battery Less consumption = Smaller size @ Equal Service Life F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 22

Voltage(Vdc) Internal Impedance (Ohms) General Requirements: Batteries (I) Lithium-Iodine Battery (Li/I 2 ) THE pacemaker battery during almost 30 years Beguining of life: 2.8V, Operation down to 2.0V. High internal impedance, specially near depletion (several kohms) Must be taken into account in complete device (power decoupling) and circuit design (instantaneous consumption, PSRR) Common problem with other nonimplantable batteries (e.g LiMn02) Capacity: In the order of 1 Ah = 114 ma. Year 3 2.5 2 1.5 1 0.5 0 Voltage Internal Impedance 0 20 40 60 80 100 16000 14000 12000 10000 8000 6000 4000 2000 Percentage of Nominal Capacity Delivered (%) 0 F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 23

General Requirements: Batteries (II) For higher instantaneous consumption devices, lower impedance required Lithium-Silver-Vanadium-Oxide (Li/SVO) Lithium-Carbon-Monofluoride (Li/CFx) QMR / QHR: Li + combined SVO / CFx Being applied also in pacemakers recently. For higher average consumption devices: Rechargeable lithium batteries (since approx. year 2000, capacity in the order of 0.3Ah) Direct powering from RF energy transmitted transcutaneously F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 24

General Requirements: Battery and Consumption Capacity: In the order of 1 Ah = 114 ma. Year Consumption Service Life: 6 to 12 years => consumption: 19 ma to 9 ma Average consumption due to stimulation (pacemakers): 3 ma to 12 ma=> Unavoidable State of the art: average consumption internal to the circuit around 5 to 10mA Consumption internal to the circuit: 50% to 75% of total consumption There is room and need for improvement F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 25

General Requirements: Safety and Reliability This is not acceptable!!! Source: Quino F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 26

General Requirements: Safety and Reliability Reliability => Frequency and probability of faults Safety: Involves many aspects, particularly: => A single fault must not provoke a catastrophic event High Reliability => + Safety Probability of single fault is low and double fault is virtually impossible => Probability of malfunctioning is low => Catastrophic Failure: virtually impossible F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 27

Involves all the stages: General Requirements: Safety and Reliability System and Circuit Design System and Circuit Verification, Qualification and Medical Validation Medical Device Application, Configuration and Use Strongly conditions design: E.g. Limiting DC leakage towards the heart under single fault conditions => external capacitors Importance of paying attention from the very beginning to applicable standards on AIMD safety, risk analysis and applicable regulations. F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 28

Introduction Bipolar (BJT) Analog Design: gm = Ic/UT Basically 1 degree of freedom: Ic MOS Analog Design: gm = f(id, W, L) 3 degrees of freedom Traditionally: only part of the design space: the strong inversion (above threshold) region F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 30

ID(A) ID(mA) MOST Inversion Regimes (1) 6 4 2 VT0 Strong Inversion (S.I.) 10-2 10-4 I D (V G -V T ) 2 Moderate inversion 0-1 0 1 2 3 VG(V) 10-6 10-8 10-10 Subthreshold Current VT0 Weak 10-12 inversion: I D e VG/(n.UT) 10-14 Leakage Current -0.5 0 0.5 1 1.5 2 2.5 VG(V) F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 31

ID(A) MOST Inversion Regimes (2) Moderate Inversion (M.I.) Strong Inversion (S.I.) I D (V G -V T ) 2 10-5 Diffusion Current Weak Inversion (W.I.) I D e VG/(n.UT) 10-10 U T =k.t/q n: slope factor Drift Current VT0 0 0.5 1 1.5 2 2.5 VG(V) F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 32

ID(A) All regions, continuous MOST models 10-5 Weak Inversion Model General Model Strong Inversion Model 10-10 10-15 Leakage Current Weak Inversion Approximate Limit VT0 Strong Inversion Approximate Limit 0 0.5 1 1.5 2 VG(V) EKV (Enz, Krummenacher, Vittoz, EPFL, AICSP 1995): originally mathematic interpolation between strong and weak inversion equations, now physical ACM (Advanced Compact Model, A. Cunha, C. Galup-Montoro, M. Schneider, UFSC, IEEE JSSC 1998): Physical model. or experimental / simulation curves F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 33

Intrinsic MOS Amplifier V DD A (db) A 0 =g m /g d vi I D vo C L f T =g m /(2..C L ) f(hz) A OTA: Operational Transconductance Amplifier 0 g g m m gm. ro. gd I D f T gm 2 C L, V A A0 A s.a 1 2 f 0 T g I m D g I d D Consumption: I D Speed g m /C L C L : total: external + parasitics Speed - Consumption tradeoff : g m /I D F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 34

ID(A) g m /I D vs. V G g I m D 1 I D I D V G log(i V G D ) g m /I D is the slope of I D vs. V G in log scale 10-2 10-4 10-6 10-8 10-10 10-12 Subthreshold Current Leakage Current VT0 10-14 -0.5 0 0.5 1 1.5 2 2.5 VG(V) Maximum in WI Equal to 1/(n.U T ) n typ: 1.3 a 1.5 F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 35

gm/id(1/v) 40 35 30 25 20 15 10 5 g m /I D vs. I D gm/ic, transistor bipolar Bipolar Transistor: g m /I C independent of current in a wide range W/L =100 and 0.8mm technology. 0 10-15 10-10 10-5 10 0 ID(A) As the current increases, the g m generation efficiency decreases To reach the maximum frequency allowed by the technology: => high g m => high current => strong inversion => low efficiency F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 36

gm/id(1/v) g m /I D and transistor size When short channel effects are not significant: m I D =mc ox (W/L).f(V G, V S, V D ) f Inorm 30 25 20 15 10 g I D I I I norm norm norm i I D ( W / L) mc f ox I I I D ( W / L) D S 5 0 10-10 10-8 10-6 10-4 10-2 ID/(W/L)(A) When short channel effects are significant: g I m D f I norm,l F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 37

gm/id (1/V) Design Methodology: g m /I D key variable VDD Vi VO 40 [Silveira, Flandre, Jespers, IEEE JSSC 1996, P.Jespers, Springer, 2010] A 0 Vi ID VO CL gm.vi gd gm 1 gm 1 VA I f T 2 C 2 C D Circuit Performance g m / I D L L g I m D CL I D 30 20 10 0 weak inv. 1/nUT mod. inv. strong inv. ID(A) 1.E-12 1.E-10 1.E-08 1.E-06 1.E-04 10-12 10-10 10-8 10-6 2/GVO Transistor Operating Mode Transistor Sizing I D =mc ox (W/L).f(V G, V S, V D ) F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 38 g I m D f I norm I I norm norm I D ( W / L) ID mc ( W / L) ox

gm/id (1/V) Optimum of Power Consumption 30 25 Weak inversion: I D e VG/(n.UT) Moderate inversion 20 15 10 Strong inversion (I D (V G -V T ) 2 ) 5 0 10-10 10-8 10-6 10-4 10-2 ID/(W/L) (A) Working towards WI g m /I D I D Usually an optimum exists W/L C g m in moderate inversion F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 39

CLtot (pf) ID (A) W1 (um) Example Intrinsic Amplifier: Power Optimum I D vi V DD vo C L f T =10MHz, C L =3pF, L=2mm, tech: 0.8mm 10 4 10-4 10 3 10 2 10 1 10 0 0 5 10 15 20 25 12 gm/id (1/V) 10 8 6 10-5 0 5 10 15 20 25 gm/id (1/V) 4 2 0 5 10 15 20 25 gm/id (1/V) F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 40

ID(A) gm/id (1/V) Example Intrinsic amplifier 0.8um, C L 3pF 1.00E+00 1.00E-01 30 25 20 15 10 5 0 10-10 10-8 10-6 10-4 10-2 ID/(W/L) (A) M.I. optimum 1.00E-02 1.00E-03 1.00E-04 1.00E-05 1.00E-06 100kHz 1MHz 10MHz 100MHz 1GHz 1.00E-07 1.00E-08 0 5 10 15 20 25 30 S.I. optimum gm/id(1/v) W.I. optimum F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 41

gm/id (1/V) gm/id in the nanometer and post CMOS era 35 30 25 20 15 10 5 L=4.0 L=0.5 L=1.0 L = 0.10, 0.11, 0.12, 0.13, 0.14 W=10um, L(um) VDS=0.6V B. Sensale-Rodriguez et al, accepted for presentation at IEEE SubVt 2012, joint work with U. Notre Dame, Indiana. 0 10-11 10-10 10-9 10-8 10-7 10-6 10-5 10-4 10-3 ID/(W/L) (A) Derived based on data from P. Jespers, The g m /I D Methodology a sizing tool for lowvoltage analog CMOS circuits, Springer, 2010, extras.springer.com F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 42

+ - ULP Analog Signal Processing: 1) RC Active Filter C Low pass filter Vin R1 R2 Vo v v o in R 2 R1 1 R.C.s 2 Limited by values possible to integrate: up to k o M (special process) and 100s pf Large spread in absolute values of integrated components => Drawback: need for external components..., but... F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 44

ULP Analog Signal Processing: External components should always be avoided? A few are required to avoid single fault risks. Full integration might be paid in terms of consumption in order to accomodate less precise components 0805 0603 0201 0402 SMT components up to 10M and 15mF 0402 SMT => 1mm x 0.5mm x 0.35mm = 0.18mm 3 Considering PCB, IC package pin, routing => 2-5 mm 3 Size and Consumption are linked through Battery size 1 Ah = 114 ma.year 11.4mA 44mm 3 / 100nA 10 year service life 5cc battery F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 45

+ - + - + - + - ULP Analog Signal Processing: 2) Switched capacitor filters Vin R1 Vo Vin 1 C1 2 Vo 2 1 2 C2 2 C 1 1 R2 Vin R1 Vo Vin 1 C1 2 C Vo 1/R2.C = fclk.c2/c 2 1 + precise, + large time constants possible, + fully integrated - op amps consumption, - antialiasing F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 46

+ - + - ULP Analog Signal Processing: 3) Gm-C Filters v+ + - gm io = gm(v+ - v-) v- C R2 vin + gm Vo Vin R1 Vo - C gm R=1/g m => 1/R2.C = g m2 /C => spread => on-chip automatic tuning + large time constants possible - input linear range requirements for transconductors F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 47

Example of modules: Pacemaker Activity Sense Objective: E.g. Activity indicator: 3s Average of the absolute value of acceleration in the 0.5-7 Hz band. Amplitude: tens to hundreds of mv Sensor Ideal Rectifier 3s Averaging Amplifier / filter F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 48

Accelerometer Signal Conditioning (1): Amplifier / Bandpass filter Input signal Vs Double input symmetrical OTA (DDA) Vo Vo=A1Vs+A2Vf Feedback signal Vf High pass characteristic ISCAS 1998 F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 49

Accelerometer Signal Conditioning (2): Layout and results Gain 2900 Equivalent input noise (mvrms) 18 Consumption (ma) 3.4 Area (mm 2 ) 1.82 F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 50

cardiac freq.(ppm) digitized output of circuit Accelerometer Signal Conditioning (3): Results 200 180 160 actual cardiac frequency of healthy patient simulated pacemaker frequency circuit output 200 180 160 140 140 120 120 100 100 80 80 60 60 40 40 20 20 0 0 0 50 100 150 200 time(s) F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 51

Accelerometer Signal Conditioning (4) : Gm-C implementation A. Arnaud (UR), C. Galup (UFSC), ISCAS 2004 Filtro-Amplificador 0.5-7Hz V Bias = 700mV C 2 =50p C 1 =550p G m1 V lin = 5mV G m3 G m2 + V Out 1 G m4 C 3 =50p G m4 =21nS G m5 =2.5nS G m6 lin =89pS = 500mV V lin Ganancia 2 a : G 2 =8.3 G m5 + V Out2 G=385 I DD = 290nA Equivalent Input noise: 2.1mVrms Gain: 390 Fully integrated V IN Sensor G m4 =21nS G m5 =2.5nS G m6 =89pS C 4 =250p G m6 Ganancia Preamplificador: G 1 =46.4 F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 52

Example of modules: Neural Recording Amplifier Objective: Signal detection from e.g: cuff electrodes or cortical electrodes arrays Requirements: 0.5mVrms - 2mVrms noise BW: 300Hz 8kHz High CMRR (particularly in Cuff) Block high DC offsets (100mV or more) due to electrode/tissue contact Negligible DC input current F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 53

Example: Cuff Electrode Recording in Neurostep Hoffer et al, IFESS 2005 Hoffer et al, US Patent 5,824,027 / 1998 F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 54

Example: Cortical Recordings Harrison, Proc. IEEE, July 2008 F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 55

Neural Amplifier Front End (1): Capacitive Feedback Inversion region for noise / power optimization: e.g. input pair weak inversion, current mirror active load: strong inversion CMRR limited by capacitor matching. Harrison et al, IEEE JSSC, June 2003 Gain 40 db BW 0.13 Hz / 7.5 khz Itotal 16 ma NEF 3.8 vnoise rms 2.1 mv CMRR > 42 db MOS Bipolar Pseudoresistor (100s Mohms equivalent) F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 56

Neural Amplifier Front End (2): DDA Based High CMRR (Given by Input Differential Pair) Both Differential Pairs contribute equally to Input Noise (hence to area and consumption) J. Sacristán, T. Oses, IFESS 2002, Another DDA Based Scheme: M. Baru, U.S. Patent 6.996.435, 2006 F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 57

Neural Amplifier Front End (3): Asymmetrical DDA Based (I) Effect of noise (and hence consumption and area) of Gm2 greatly reduced while keeping high CMRR (given by input differential pair) Gm2 less effective in compensating input offset and DC components => Output DC and high pass characteristic fixed by local feedback at the output P. Castro, F. Silveira, ISCAS 2011 F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 58

Neural Amplifier Front End (4): Asymmetrical DDA Based (II) Spec Castro, ISCAS 2011 Harrison, JSSC 2003 Wattapanitch, TR. BIOCAS 2007 Sacristan, IFESS 2002 Architecture Asym. DDA Capacitive Capacitive DDA A (db) 48 40 41 80 NEF 4.2 3.8 2.7 53.4 Itotal(mA) 16.5 16.0 2.7 180 vi noise (mvrms) 2.4 2.1 3.1 7.6 CMRR > 107 > 42 > 66 90 F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 59

Prospects: Digital vs. Analog Scaling Theoretical limits of power consumption for Analog and Digital Signal Processing Analog better for low S/N, but the border is moving... Digital pacemaker already present in marketing Source: E. Vittoz F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 61

Prospects: Analog ULP and AIMD Intense growth of applications / therapies on development and reaching the market Broad Analog / Circuit research area: Sensing Stimulation, Power Management / Battery Recharge, Communication, Once very specific area, now wider (wireless sensor networks, body area networks, portable devices, energy scavenging devices, RFID,...). F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 62

Prospects: AIMDs Brain Computer Interface Set. 2000, Nicolelis, Duke University F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 63

Prospects: AIMDs Brain Computer Interface Mar. 2002, M. Serruya, J. Donoghue, Brown University F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 64

Prospects AIMDs: Brain Computer Interface July 2004: Pilot FDA trial started by spin/off company of Brown Univ., several tetraplegic patients implanted. F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 65

Some Conclusions ULP ICs for AIMDs: Each na counts => Methodology and Optimization AIMDs: Very broad field in strong expansion Many R & D opportunities Microtechnology is often the enabling factor. AIMDs: Price is not the main concern, but application and performance Suitable for developments with lower volume productions than in other areas High investment associated with long development cycles, qualification, clinical testing and regulatory aspects. F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 66

Microelectronics Group IIE Universidad de la República More Information iie.fing.edu.uy/vlsi silveira@fing.edu.uy Acknowledgements IEEE CASS CCC Medical Devices, NanoWattICs Members (present and past) of Microelectronics Group, UR F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 67

Thank you! F. Silveira, Univ. de la República, Montevideo, Uruguay IEEE CASS DLP 68