Datasheet

TMP411-Q1
www.ti.com SBOS527F –DECEMBER 2010–REVISED NOVEMBER 2013
SERIES RESISTANCE CANCELLATION TEMPERATURE MEASUREMENT DATA
Series resistance in an application circuit that typically Temperature measurement data are taken over a
results from printed circuit board (PCB) trace default range of 0°C to 127°C for both local and
resistance and remote line length (see Figure 11) is remote locations. Measurements from –55°C to
automatically cancelled by the TMP411-Q1, 150°C can be made both locally and remotely by
preventing what would otherwise result in a reconfiguring the TMP411-Q1 for the extended
temperature offset. temperature range. To change the TMP411-Q1
configuration from the standard to the extended
A total of up to 3 kΩ of series line resistance is
temperature range, switch bit 2 (RANGE) of the
cancelled by the TMP411-Q1, eliminating the need
Configuration Register from low to high.
for additional characterization and temperature offset
correction. Temperature data resulting from conversions within
the default measurement range are represented in
See the two Remote Temperature Error vs Series
binary form, as shown in Table 2, Standard Binary
Resistance typical characteristics curves (Figure 4
column. Note that any temperature below 0°C results
and Figure 5) for details on the effect of series
in a data value of zero (00h). Likewise, temperatures
resistance and power-supply voltage on sensed
above 127°C result in a value of 127 (7Fh). The
remote temperature error.
device can be set to measure over an extended
temperature range by changing bit 2 of the
DIFFERENTIAL INPUT CAPACITANCE
Configuration Register from low to high. The change
in measurement range and data format from standard
The TMP411-Q1 tolerates differential input
binary to extended binary occurs at the next
capacitance of up to 1000 pF with minimal change in
temperature conversion. For data captured in the
temperature error. The effect of capacitance on
extended temperature range configuration, an offset
sensed remote temperature error is illustrated in
of 64 (40h) is added to the standard binary value, as
typical characteristic Remote Temperature Error vs
shown in Table 1, Extended Binary column. This
Differential Capacitance (Figure 6).
configuration allows measurement of temperatures
below 0°C. Note that binary values corresponding to
temperatures as low as –64°C, and as high as 191°C
are possible; however, most temperature-sensing
diodes only measure with the range of –55°C to
150°C. Additionally, the TMP411-Q1 is rated only for
ambient local temperatures ranging from –40°C to
125°C. Parameters in the Absolute Maximum Ratings
table must be observed.
Table 2. Temperature Data Format
(Local and Remote Temperature High Bytes)
LOCAL/REMOTE TEMPERATURE REGISTER HIGH BYTE VALUE (1°C RESOLUTION)
TEMP (°C) STANDARD BINARY EXTENDED BINARY
BINARY HEX BINARY HEX
−64 0000 0000 00 0000 0000 00
−50 0000 0000 00 0000 1110 0E
−25 0000 0000 00 0010 0111 27
0 0000 0000 00 0100 0000 40
1 0000 0001 01 0100 0001 41
5 0000 0101 05 0100 0101 45
10 0000 1010 0A 0100 1010 4A
25 0001 1001 19 0101 1001 59
50 0011 0010 32 0111 0010 72
75 0100 1011 4B 1000 1011 8b
100 0110 0100 64 1010 0100 A4
125 0111 1101 7D 1011 1101 BD
127 0111 1111 7F 1011 1111 BF
150 0111 1111 7F 1101 0110 D6
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