TEMPERATURE REGISTER

CONFIGURATION REGISTER

SHUTDOWN MODE (SD)

TMP122-EP

Table 3. Pointer Addresses

P1

P0

REGISTER

0

0

Temperature Register (READ only)

0

1

Configuration Register (READ/WRITE)

1

0

1

1

The Temperature Register of the TMP122 is a 16-bit, signed read-only register that stores the output of the most

recent conversion. The TMP122 is specified for the temperature range of -55°C to 125°C with operation from

-55°C to 150°C. Up to 16 bits can be read to obtain data and are described in Table 4. The first 13 bits are used

to indicate temperature where bit D2 is 1, and D1, D0 are in a high impedance state. Data format for temperature

is summarized in Table 5. Following power-up or reset, the Temperature Register will read 0°C until the first

conversion is complete.

Table 4. Temperature Register

D15

D14

D13

D12

D11

D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

T12

T11

T10

T9

T8

T7

T6

T5

T4

T3

T2

T1

T0

1

Z

Z

Table 5. Temperature Data Format

TEMPERATURE

HEX

(°c)

(BINARY)

150

0100 1011 0000 0111

4B07

125

0011 1110 1000 0111

3E87

25

0000 1100 1000 0111

0C87

0.0625

0000 0000 0000 1111

000F

0

0000 0000 0000 0111

0007

-0.0625

1111 1111 1111 1111

FFFF

-25

1111 0011 1000 0111

F387

-55

1110 0100 1000 0111

E487

(1)

The last two bits are high impedance and are shown as 11 in the table.

The user can obtain 9, 10, 11, or 12 bits of resolution by addressing the Configuration Register and setting the

resolution bits accordingly. For 9-, 10-, or 11-bit resolution, the most significant bits in the Temperture Register

are used with the unused LSBs set to zero.

The Configuration Register is a 16-bit read/write register used to store bits that control the operational modes of

the temperature sensor. Read/write operations are performed MSB first. The format of the Configuration Register

for the TMP122 is shown in Table 6, followed by a break-down of the register bits. The power-up/reset value of

the Configuration Register bits R1/R0 equal 1/1, all other bits equal zero.

Table 6. Configuration Register

D15

D14

D13

D12

D11

D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

0

0

0

0

D1

D0

R1

R0

F1

F0

POL

TM1

TM0

0

1

0

The Shutdown Mode of the TMP122 can be used to shut down all device circuitry except the serial interface.

Shutdown mode occurs when the last 8 bits of the WRITE command are equal to 1, and will occur once the

current conversion is completed, reducing current consumption to less than 1

µA. To take the part out of

shutdown, send any command or pattern after the 16-bit read with the last 8 bits not equal to one. Power on

default is in active mode.

8

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