MIC281
Slave Address
The MIC281 will only respond to its own unique slave ad-
dress. A match between the MIC281’s address and the
address specified in the serial bit stream must be made to
initiate communication. The MIC281’s slave address is fixed
at the time of manufacture. Eight different slave addresses
are available as determined by the part number. See Table
2 below and the Ordering Information table.
Part Number
MIC281-0BM6
MIC281-1BM6
MIC281-2BM6
MIC281-3BM6
MIC281-4BM6
MIC281-5BM6
MIC281-6BM6
MIC281-7BM6
Slave Address
1001 000x
b
= 90
h
1001 001x
b
= 92
h
1001 010x
b
= 94
h
1001 011x
b
= 96
h
1001 100x
b
= 98
h
Temperature
+127°C
+125°C
+25°C
+1°C
0°C
–1°C
–25°C
–125°C
–128°C
Binary
0111 1111
0111 1101
0001 1001
0000 0001
0000 0000
1111 1111
1110 0111
1000 0011
1000 0000
Hex
7F
7D
19
01
00
FF
E7
83
80
Micrel
Table 3. Digital Temperature Format
Diode Faults
The MIC281 is designed to respond in a failsafe manner to
diode faults. If an internal or external fault occurs in the tem-
perature sensing circuitry, such as T1 being open or shorted
to V
DD
or GND, the temperature result will be reported as the
maximum full-scale value, +127°C. Note that diode faults will
not be detected until the first A/D conversion cycle is completed
following power-up or exiting shutdown mode.
Shutdown Mode
Setting the shutdown bit in the configuration register will
cause the MIC281 to cease operation. The A/D converter will
stop and power consumption will drop to the I
SHDN
level. No
registers will be affected by entering shutdown mode. The
last temperature reading will persist in the TEMP register.
1001 101x
b
= 9A
h
1001 110x
b
= 9C
h
1001 111x
b
= 9E
h
Table 2. MIC281 Slave Addresses
Temperature Data Format
The least-significant bit of the temperature register represents
one degree Centigrade. The values are in a two’s comple-
ment format, wherein the most significant bit (D7) represents
the sign: zero for positive temperatures and one for negative
temperatures. Table 3 shows examples of the data format
used by the MIC281 for temperatures.
November 2004
7
MIC281
MICREL [ MICREL SEMICONDUCTOR ]
