MIC281 Micrel Semiconductor, MIC281 Datasheet - Page 7

• Manufacturer Part Number: MIC281
• Description: Thermal Sensor IttyBitty
• Manufacturer: Micrel Semiconductor

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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.
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
Table 2. MIC281 Slave Addresses
Part Number
MIC281-0BM6
MIC281-1BM6
MIC281-2BM6
MIC281-3BM6
MIC281-4BM6
MIC281-5BM6
MIC281-6BM6
MIC281-7BM6
Slave Address
1001 000x
1001 001x
1001 010x
1001 011x
1001 100x
1001 101x
1001 110x
1001 111x
b
b
b
b
b
b
b
b
= 9E
= 96
= 9C
= 90
= 92
= 94
= 98
= 9A
h
h
h
h
h
h
h
h
7
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
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
registers will be affected by entering shutdown mode. The
last temperature reading will persist in the TEMP register.
DD
Temperature
or GND, the temperature result will be reported as the
+127°C
+125°C
–125°C
–128°C
+25°C
–25°C
+1°C
–1°C
Table 3. Digital Temperature Format
0°C
0001 1001
0000 0001
0000 0000
1000 0000
1000 0011
0111 1101
0111 1111
1110 0111
1111 1111
Binary
SHDN
Hex
7D
FF
E7
7F
19
01
00
83
80
level. No
MIC281