Datasheet

 2015-2017 Microchip Technology Inc. DS20005426C-page 25
MCP9600
5.1.2 THERMOCOUPLE JUNCTIONS
DELTA TEMPERATURE
REGISTER (T
∆
)
This register contains the error corrected
Thermocouple Hot-Junction temperature without the
Cold-Junction compensation. The error correction
methodology uses several coefficients to convert the
digitized Thermocouple EMF voltage to degree
Celsius. Each Thermocouple type has a unique set of
coefficients as specified by NIST, and these
coefficients are available in the configuration register
for user selection as shown in Figure 5-3.
EQUATION 5-2: TEMPERATURE
CONVERSION
The temperature bits are in two’s complement format,
therefore, positive temperature data and negative
temperature data are computed differently, as shown
in Equation 5-2.
FIGURE 5-3: Thermocouple Hot-Junction
Register (T
∆
) Block Diagram.
Temperature  0°C
T
∆
= (UpperByte x 16 + LowerByte / 16)
Temperature  0°C
T
∆
= (UpperByte x 16 + LowerByte / 16) - 4096
V
IN+
V
IN-
ADC code to
degree Celsius
conversion using
coefficients derived
from NIST look-up
table database
User-Selectable,
Thermocouple Types:
- Type K
- Type J
- Type T
- Type N
- Type S
- Type E
- Type B
- Type R
(see Register 5-6)
Thermocouple
Junctions Delta
Temperature – T
∆
Check if the ADC
code is within range
for the selected
thermocouple type
T
∆
Delta-Sigma
18-Bit
ADC Core
ADC
REGISTER 5-3: HOT-JUNCTION TEMPERATURE REGISTER (READ-ONLY)
R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0
SIGN 1024°C 512°C 256°C 128°C 64°C 32°C 16°C
bit 15 bit 8
R-0 R-0 R-0 R-0 R-0 R-0 R-0 R-0
8°C 4°C 2°C 1°C 0.5°C 0.25°C 0.125°C 0.0625°C
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 15 SIGN: Sign bit
1 =T
A
 0°C
0 =T
A
0°C
bit 14-0 T
∆
: Data in Two’s Complement Format bits
This register contains Thermocouple Hot-Junction temperature data.