TCM1617 Datasheet, PDF (11/14 Pages) Microchip Technology – SMBus Thermal Sensor with External Diode Input

SMBus Thermal Sensor with External Diode Input
TCM1617
Temperature Registers, 8-Bits, Read-Only
(INT_TEMP, EXT_TEMP)
The binary value (2’s complement format) in these two
registers represents temperature of the internal and external
sensors following a conversion cycle. The registers are
automatically updated in an alternating manner.
Internal Temperature Register (INT_TEMP)
D[7] D[6] D[5] D[4] D[3] D[2] D[1] D[0]
MSB x
x
x
x
x
x LSB
External Temperature Register (EXT_TEMP)
D[7] D[6] D[5] D[4] D[3] D[2] D[1] D[0]
MSB x
x
x
x
x
x LSB
In the two temperature data and four threshold setpoint
registers, each unit value represents one degree (Celsius).
The value is in 2’s-complement binary format such that a
reading of 00000000b corresponds to 0°C. Examples of this
temperature-to-binary value relationship are shown in the
following table.
Temperature-to-Digital Value Conversion
(INT_TEMP, EXT_TEMP, INT_HLIM, INT_LLIM,
EXT_HLIM, EXT_LLIM)
Actual
Temperature
+130.00°C
+127.00°C
+126.50°C
+25.25°C
+0.50°C
+0.25°C
0.00°C
–0.25°C
–0.50°C
–0.75°C
–1.00°C
–25.00°C
–25.25°C
–54.75°C
–55.00°C
–65.00°C
Rounded
Temperature
+127°C
+127°C
+127°C
+25°C
+1°C
0°C
0°C
0°C
0°C
–1°C
–1°C
–25°C
–25°C
–55°C
–55°C
–65°C
Binary
Value
01111111
01111111
01111111
00011001
00000001
00000000
00000000
00000000
00000000
11111111
11111111
11100111
11100110
11001001
11001001
10111111
Hex
Value
7F
7F
7F
19
01
00
00
00
00
FF
FF
E7
E7
C9
C9
BF
Temperature Threshold Setpoint Registers,
8-Bits, Read-Write (INT_HLIM, INT_LLIM,
EXT_HLIM, EXT_LLIM)
These registers store the values of the upper and lower
temperature setpoints for event detection. The value is in
2’s-complement binary. INT_HLIM and INT_LLIM are com-
pared with the INT_TEMP value, and EXT_HLIM and
EXT_LLIM are compared with EXT_TEMP. These registers
may be written at any time.
Internal High Limit Setpoint Register (INT_HLIM)
D[7] D[6] D[5] D[4] D[3] D[2] D[1] D[0]
MSB x
x
x
x
x
x LSB
Internal Low Limit Setpoint Register (INT_LLIM)
D[7] D[6] D[5] D[4] D[3] D[2] D[1] D[0]
MSB x
x
x
x
x
x LSB
External High Limit Setpoint Register (EXT_HLIM)
D[7] D[6] D[5] D[4] D[3] D[2] D[1] D[0]
MSB x
x
x
x
x
x LSB
External Low Limit Setpoint Register (EXT_LLIM)
D[7] D[6] D[5]
MSB x
x
NOTE: POR states:
INT_HLIM
INT_LLIM
EXT_HLIM
EXT_LLIM
D[4] D[3]
x
x
01111111b
11001001b
01111111b
11001001b
D[2] D[1] D[0]
x
x LSB
+127°C
–55°C
+127°C
–55°C
 2001 Microchip Technology Inc. DS21485A
11
TCM1617-1 2/5/99