RESULTS
Temperature measurements were made using a custom-built
apparatus, as shown in Fig. 5, using a Ni-Fe thermistor with
±0.1 ◦C accuracy from −240 ◦C to +260 ◦C. Resistors measuring
100 Ω and rated at 5 W were used to heat the enclosed
space to 80 ◦C (measured in 2 ◦C increments by attaching the
thermistor to the chip), and temperatures down to 5 ◦C were
measured in an ice bath. System performance is summarized
in Table II. The reported energy is the product of the sample
latency and average power while the sensors are active and
depends on the operating temperature. (The reported power and
energy are at 27 ◦C.)