Datasheet

TMP512
TMP513
SBOS491A –JUNE 2010– REVISED MAY 2011 www.ti.com
SERIES RESISTANCE CANCELLATION Local Temperature Result Register and the Remote
Temperature Result Registers. Note that byte 1 is the
Series resistance in an application circuit that typically
most significant byte, followed by byte 2, the least
results from printed circuit board (PCB) trace
significant byte. The first 13 bits are used to indicate
resistance and remote line length is automatically
temperature. The least significant byte does not have
cancelled by the TMP512/13, preventing what would
to be read if that information is not needed. The data
otherwise result in a temperature offset. A total of up
format for temperature is summarized in Table 10.
to 3kΩ of series line resistance is cancelled by the
One LSB equals 0.0625°C. Negative numbers are
TMP512/13, eliminating the need for additional
represented in binary twos complement format.
characterization and temperature offset correction.
Following power-up or reset, the Temperature
See the Remote Temperature Error vs Series
Register will read 0°C until the first conversion is
Resistance typical characteristic curves (Figure 15 )
complete. Unused bits in the Temperature Register
for details on the effects of series resistance and
always read '0'.
power-supply voltage on sensed remote temperature
error.
REGISTER INFORMATION
DIFFERENTIAL INPUT CAPACITANCE The TMP512/13 contain multiple registers for holding
configuration information, temperature and voltage
The TMP512/13 can tolerate differential input
measurement results, and status information. These
capacitance of up to 2200pF with minimal change in
registers are described in Table 3.
temperature error. The effect of capacitance on
sensed remote temperature error is illustrated in
POINTER REGISTER
Figure 16, Remote Temperature Error vs Differential
Capacitance. See the Filtering section for suggested
The 8-bit Pointer Register is used to address a given
component values where filtering unwanted coupled
data register. The Pointer Register identifies which of
signals is needed.
the data registers should respond to a read or write
command on the two-wire bus. This register is set
TEMPERATURE MEASUREMENT DATA with every write command. A write command must be
issued to set the proper value in the Pointer Register
Temperature measurement data may be taken over
before executing a read command. Table 3 describes
an operating range of –40°C to +125°C for both local
the pointer address of the TMP512/13 registers. The
and remote locations.
power-on reset (POR) value of the Pointer Register is
00h (0000 0000b).
The Temperature Register of the TMP512/13 is
configured as a 13-bit, read-only register that stores
the output of the most recent conversion. Two bytes
must be read to obtain data, and are described in the
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