1. A Low Power Carbon Nanotube Chemical Sensor System
Ultra-Low power operation for prolonged operation
High sensitivity to chemicals with fast response time
High selectivity to differentiate chemicals
Chemical Sensor Node Design Criteria
Briefly explain the design criteria for stand-alone chemical sensor nodes
Briefly explain why CNT sensors are good, and explain the overall system. 1

2. Measured CNT Characteristics10 3 4 5 6 7 8 9 20 40 60 80
Resistance ( W
) samples
Device Count R
CNT
Distribution
Wide dynamic range (10kΩ ~ 9MΩ), but only moderate resolution (1%)
Sub-ppm NO2 detection
16 bit dynamic range
6-7 bit resolution
Interface to multiple CNT sensors for increased reliability
Access to 24 CNTs
Maximum current through a single CNT < 30 μA
Implications for the CMOS chip
500
1000
1500
2000
2500
3000
3500 R O (k W ) D
R (k
R vs. R
(300ppm NO 2

3. CMOS Chip Architecture
CMOS Chip Design
CMOS Chip Architecture
Chip Design Flow
Achieves a wide dynamic range with ADC/DAC of lower dynamic range
Dynamic range allocation is optimized by modeling each block
Consumes 32 μW at 1.83kS/s at less than 1.34% measurement error
Briefly mention the overall architecture – how to attain a wide dynamic range.
Mention that the optimization is performed to allocate bits to the blocks
Mention the system performance.
Mention the acknowledgments
Acknowledgments : FCRP IFC, National Semiconductor Inc., Samsung Scholarship Foundation, Intel 3