ADIS16006 Data Sheet
Rev. C | Page 12 of 16
TEMPERATURE SENSOR SERIAL INTERFACE
Read Operation
Figure 4 shows the timing diagram for a serial read from the
temperature sensor. The
TCS
line enables the SCLK input.
Ten bits of data and a leading zero are transferred during a read
operation. Read operations occur during streams of 16 clock
pulses. The serial data can be received into two bytes to
accommodate the entire 10-bit data stream. If only eight bits
of resolution are required, the data can be received into a single
byte. At the end of the read operation, the DOUT line remains
in the state of the last bit of data clocked out until
TCS
goes
high, at which time the DOUT line from the temperature
sensor goes three-state.
Write Operation
Figure 4 also shows the timing diagram for the serial write
to the temperature sensor. The write operation takes place at
the same time as the read operation. Data is clocked into the
control register on the rising edge of SCLK. DIN should remain
low for the entire cycle.
Temperature Sensor Control Register
MSB LSB
ZERO ZERO ZERO ZERO ZERO ZERO ZERO ZERO
Table 8. Temperature Sensor Control Register Bit Functions
7 to 0 ZERO All bits should be held low.
ZERO
ZERO is defined as the Logic low level.
Output Data Format
The output data format for the temperature sensor is twos
complement. Table 9 shows the relationship between the
temperature and the digital output.
Table 9. Temperature Sensor Data Format
Temperature Digital Output (DB9 … DB0)
−40°C 11 0110 0000
−25°C 11 1001 1100
−0.25°C 11 1111 1111
0°C 00 0000 0000
+0.25°C 00 0000 0001
+25°C 00 0110 0100
+50°C 00 1100 1000
+75°C 01 0010 1100
+100°C 01 1001 0000
Temperature Sensor Conversion Details
The ADIS16006 features a 10-bit digital temperature sensor that
allows an accurate measurement of the ambient device temperature
to be made.
The conversion clock for the temperature sensor is internally
generated; therefore, no external clock is required except when
reading from and writing to the serial port. In normal mode, an
internal clock oscillator runs the automatic conversion sequence. A
conversion is initiated approximately every 350 µs. At this time,
the temperature sensor wakes up and performs a temperature
conversion. This temperature conversion typically takes 25 µs,
at which time the temperature sensor automatically shuts down.
The result of the most recent temperature conversion is avail-
able in the serial output register at any time. Once the conversion is
finished, an internal oscillator starts counting and is designed to
time out every 350 µs. The temperature sensor then powers up
and does a conversion.
If the
TCS
is brought low every 350 µs (±30%) or less, the same
temperature value is output onto the DOUT line every time
without changing. It is recommended that the
TCS
line not
be brought low every 350 µs (±30%) or less. The ±30% covers
process variation. The
TCS
should become active (high to low)
outside this range.
The device is designed to autoconvert every 350 µs. If the
temperature sensor is accessed during the conversion process,
an internal signal is generated to prevent any update of the
temperature value register during the conversion. This prevents
the user from reading back spurious data. The design of this
feature results in this internal lockout signal being reset only at
the start of the next autoconversion. Therefore, if the
TCS
line
goes active before the internal lockout signal is reset to its inactive
mode, the internal lockout signal is not reset. To ensure that no
lockout signal is set, bring
TCS
low at a greater time than 350 µs
(±30%). As a result, the temperature sensor is not interrupted
during a conversion process.
In the automatic conversion mode, every time a read or write
operation takes place, the internal clock oscillator is restarted at
the end of the read or write operation. The result of the conversion
is typically available 25 µs later. Reading from the device before
conversion is complete provides the same set of data.
POWER SUPPLY DECOUPLING
The ADIS16006 integrates two decoupling capacitors that are
0.047 µF in value. For local operation of the ADIS16006, no
additional power supply decoupling capacitance is required.
However, if the system power supply presents a substantial
amount of noise, additional filtering can be required. If additional
capacitors are required, connect the ground terminal of each
of these capacitors directly to the underlying ground plane.
Finally, note that all analog and digital grounds should be
referenced to the same system ground reference point.
