Datasheet

ADT7301
Rev. 0 | Page 10 of 16
TEMPERATURE VALUE REGISTER
The temperature value register is a 14-bit read only register that
stores the temperature reading from the ADC in 13-bit twos
complement format plus a sign bit. The MSB (DB13) is the sign
bit. The ADC can theoretically measure a 255°C temperature
span. The internal temperature sensor is guaranteed to a low
value limit of –40°C and a high limit of +150°C. The temperature
data format is shown in Tabl e 5 , which shows the temperature
measurement range of the device (–40°C to +150°C). The
typical performance curve is shown in
Figure 11.
Table 5. Temperature Data Format
Temperature Digital Output DB13 … DB0
−40°C 11, 1011 0000 0000
−30°C 11, 1100 0100 0000
−25°C 11, 1100 1110 0000
−10°C 11, 1110 1100 0000
−0.03125°C 11, 1111 1111 1111
0°C 00, 0000 0000 0000
+0.03125°C 00, 0000 0000 0001
+10°C 00, 0001 0100 0000
+25°C 00, 0011 0010 0000
+50°C 00, 0110 0100 0000
+75°C 00, 1001 0110 0000
+100°C 00, 1100 1000 0000
+125°C 00, 1111 1010 0000
+150°C 01, 0010 1100 0000
Temperature Conversion Equations
Positive Temperature = ADC Code(d)/32
Negative Temperature = (ADC Code(d)
1
− 16384)/32
Negative Temperature = (ADC Code(d)
2
− 8192)/32
DIGITAL OUTPUT
–40°C
–0.03125°C
–30°C
11, 1111, 1111, 1111
11, 1100, 0100, 0000
11, 1011, 0000, 0000
TEMPERATURE (°C)
75°C
02884-0-006
150°C
01, 0010, 1100, 0000
00, 1001, 0110, 0000
00, 0000, 0000, 0001
Figure 13. Temperature-to-Digital Transfer Function
1
ADC code uses all 14 bits of the data byte, including the sign bit.
2
DB13 (the sign bit) is removed from the ADC code.