Datasheet

Celsius
Volts
0 50 100
0.350
0.250
0.300
0.400
0.450
0.500
−50
0.200
V
Sensor,typ
= TC
Sensor
(273 + T[
o
C]) + V
Offset, sensor
[mV]
Channel 0
SD24SNGL = 0
SD24GRP = 1
Time
Conversion
SD24SC
Channel 1
SD24SNGL = 1
SD24GRP = 1
Conversion
Channel 2
SD24SNGL = 0
SD24GRP = 0
Conversion
SD24SC
SD24SC
Conversion Conversion
Set by Ch2 Auto−clear
Set by Ch2
Conv
Set by SW
Conversion
Set by SW Auto−clear
(syncronized to master)
Cleared by SW
Conv
Set by SW
(syncronized to master)
= Result written to SD24MEMx
PRE1 PRE1
PRE0
Conversion
PRE0 Conv
www.ti.com SD24_A Operation
Figure 27-11. Preload and Channel Synchronization
27.2.11 Using the Integrated Temperature Sensor
To use the on-chip temperature sensor, the user selects the analog input pair SD24INCHx = 110 and sets
SD24REFON = 1. Any other configuration is done as if an external analog input pair was selected,
including SD24INTDLYx and SD24GAINx settings. Because the internal reference must be on to use the
temperature sensor, it is not possible to use an external reference for the conversion of the temperature
sensor voltage. Also, the internal reference will be in contention with any used external reference. In this
case, the SD24VMIDON bit may be set to minimize the affects of the contention on the conversion.
The typical temperature sensor transfer function is shown in Figure 27-12. When switching inputs of an
SD24_A channel to the temperature sensor, adequate delay must be provided using SD24INTDLYx to
allow the digital filter to settle and assure that conversion results are valid. The temperature sensor offset
error can be large, and may need to be calibrated for most applications. See device-specific data sheet for
temperature sensor parameters.
Figure 27-12. Typical Temperature Sensor Transfer Function
629
SLAU144J–December 2004–Revised July 2013 SD24_A
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