MAX31725MTA View Datasheet(PDF) - Maxim Integrated

Part Name

Description

MFG CO.

MAX31725MTA

±0.5°C Local Temperature Sensors

Maxim Integrated 

MAX31725/MAX31726

±0.5°C Local Temperature Sensors

Perform a read operation by issuing the slave address

byte (write), pointer byte, repeat START, another slave

address byte (read), and then reading the data byte.

After 2 data bytes the pointer register auto increments

and, if pointing to a valid address, additional data can be

read. See Figure 4.

Temperature Registers

Temperature data is stored in the temperature, TOS set

point, and THYST set point registers. The temperature

data format is 16 bits, two’s complement, and the register

is read out in 2 bytes: an upper byte and a lower byte.

Bits D[15:0] contains the temperature data, with the LSB

representing 0.00390625NC and the MSB representing

the sign bit; see Table 3. The MSB is transmitted first.

In addition to the normal two’s complement temperature

data format, the MAX31725 and MAX31726 offer an

optional extended data format that allows temperatures

equal to or greater than +128NC to be read. In the

extended format, selected by bit 5 of the configuration

register, the measured temperature is the value in the

temperature register plus 64NC, as shown in Table 4.

1

91

9

1

91

9

1

START

BY

MASTER

0 D5* D4* D3* D2* D1* R/W

0 0 0 0 0 0 D1 D0

1 0 D5* D4* D3* D2* D1* R/W

D7 D6 D5 D4 D3 D2 D1 D0

STOP

COND BY

MASTER

ADDRESS

BYTE

ACK BY

MAX31725/

MAX31726

POINTER

BYTE

ACK BY

MAX31725/

MAX31726

REPEAT

START

BY

MASTER

ADDRESS

BYTE

ACK BY

MAX31725/

MAX31726

DATA

BYTE

NO

ACK BY

MASTER

(a) TYPICAL POINTER SET FOLLOWED BY IMMEDIATE READ FROM CONFIGURATION REGISTER.

1

91

9

1 0 D5* D4* D3* D2* D1* R/W

0 0 0 0 0 0 D1 D0

START

BY

MASTER

ADDRESS BYTE

ACK BY

MAX31725/

MAX31726

POINTER BYTE

ACK BY

MAX31725/

MAX31726

1

91

91

9

REPEAT

START

BY

MASTER

*SEE TABLE 1A.

1 0 D5* D4* D3* D2* D1* R/W

D7 D6 D5 D4 D3 D2 D1 D0

D7 D6 D5 D4 D3 D2 D1 D0

STOP

COND BY

ADDRESS

BYTE

ACK BY

MAX31725/

MAX31726

MOST SIGNIFICANT

DATA BYTE

ACK BY

MASTER

LEAST SIGNIFICANT

DATA BYTE

NO

ACK BY

MASTER

MASTER

(b) TYPICAL POINTER SET FOLLOWED BY IMMEDIATE READ FOR 2-BYTE REGISTER SUCH AS TEMPERATURE, TOS, AND THYST.

Figure 4. I2C-Compatible Timing Diagram (Read)

Table 3. Temperature, THYST, and TOS Register Definition

UPPER BYTE

LOWER BYTE

D15 D14 D13 D12 D11 D10 D9 D8 D7

D6

D5

D4

D3

D2

D1

D0

MSB

S 64NC 32NC 16NC 8NC 4NC 2NC 1NC 0.5NC 0.25NC 0.125NC 0.0625NC 0.03125NC 0.015625NC 0.0078125NC 0.00390625NC

26

25

24

23

22 21 20

2-1

2-2

2-3

2-4

2-5

2-6

2-7

2-8

Maxim Integrated

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