TSC2101-Audio Codec w/ Integrated Headphone Speaker Amp ...

SLAS392C− JUNE 2003 − REVISED SEPTEMBER 2004www.ti.com0.200°CError in Measurement −−0.20−0.40−0.60−0.80−1−1.20−40 −20 0 20 40 60 80 100TA − Free-Air Temperature − CFigure 31. Typical Plot of Single Measurement Method After Calibrating for Offset and Gain At TwoTemperaturesThe second mode uses a two-measurement (differential) method. This mode requires a second conversion witha current 82 times larger. The voltage difference between the first (TEMP1) and second (TEMP2) conversion,using 82 times the bias current, is represented by:kTq ln(N)where:N is the current ratio = 82k = Boltzmann’s constant (1.38054 • 10 −23 electrons volts/degrees Kelvin)q = the electron charge (1.602189 • 10 −19 °C)T = the temperature in degrees KelvinThe equation for the relation between differential code and temperature may vary slightly from device to deviceand can be calibrated at final system test by the user. This method provides resolution of approximately1.5°C/LSB and accuracy of approximately ±4°C after calibrating at room temperature.40