LTC2983_15 Datasheet, PDF (50/72 Pages) Linear Technology – Multi-Sensor High Accuracy Digital Temperature Measurement System

LTC2983
Applications Information
Example: Shared/Rotated Differential Thermistor
The differential thermistor configuration allows separate
internal ground sensing for each sensor. In this configura-
tion, one sense resistor can be used for multiple thermis-
tors. Differential thermistors follow the convention shown
in Figure 28. Terminal 1 ties to CH_THERM and terminal 2
ties to CH_THERM-1 and the sense resistor. Channel assign-
ment data (see Table 50) is mapped to memory locations
corresponding to CH_THERM.
Sense resistor channel assignments follow the general
convention shown in Figure 29. The sense resistor is tied
between CH_RSENSE and CH_RSENSE-1, where CH_SENSE is tied
to the 2nd terminal of the thermistor. Channel assignment
data (see Table 33) is mapped into a memory location
corresponding to CH_THERM.
Figure 30 shows a typical temperature measurement
system using a shared sense resistor and one rotated/
one non-rotated differential thermistors. In this example
EXCITATION
CURRENT
FLOW
2ND TERMINAL TIES TO SENSE RESISTOR
2
CH_THERM–1
1
CH_THERM
CHANNEL
ASSIGNMENT
= CH_THERM (2 ≤ THERM ≤ 20)
2983 F28
Figure 28. Thermistor with Shared R_SENSE Channel
Assignment Convention
EXCITATION
CURRENT
FLOW
R_SENSE
CH_RSENSE-1
CH_RSENSE
CHANNEL
ASSIGNMENT
= CH_RSENSE (2 ≤ RSENSE ≤ 20)
2983 F29
Figure 29. Sense Resistor Channel Assignment
Convention for Thermistors
2983fa
50
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