Datasheet

71M6543F/71M6543G Data Sheet

54 v2

read and properly combined to form the STEMP[10:0] 11-bit value (see STEMP in Table 45). The resulting

11-bit value is in 2’s complement form and ranges from -1024 to +1023 (decimal).

The equations below are used to calculate the sensed temperature. The first equation applies when the

71M6543F and 71M6543G are in MSN mode and TEMP_PWR = 1. The second equation applies when the

71M6543F and 71M6543G are in BRN mode, and in this case, the TEMP_PWR and TEMP_BSEL bits must

both be set to the same value, so that the battery that supplies the temperature sensor is also the battery

that is measured and reported in BSENSE. Thus, the second equation requires reading STEMP and

BSENSE. In the second equation, BSENSE (the sensed battery voltage) is used to obtain a more accurate

temperature reading when the IC is in BRN mode. The coefficients provided in the various STEMP

equations below are typical.

For the 71M6543F and 71M6543G in MSN Mode (with TEMP_PWR = 1):

22325.0)( +⋅=° STEMPCTemp

For the 71M6543F and 71M6543G in BRN Mode, (with TEMP_PWR=TEMP_BSEL):

4.64609.000218.0325.0)(

+⋅−⋅+⋅= BSENSEBSENSESTEMPCTemp

Table 45 shows the I/O RAM registers used for temperature and battery measurement.