emc1413 Standard Microsystems Corp., emc1413 Datasheet - Page 23

• Manufacturer Part Number: emc1413
• Description: 1?c Temperature Sensor With Beta Compensation And Selectable Address
• Manufacturer: Standard Microsystems Corp.

1°C Temperature Sensor with Beta Compensation and Selectable Address
Datasheet
SMSC EMC1413 / EMC1414
5.10
5.11
Diode Fault
-1
0
0.125
1
64
65
127
127.875
128
-64
TEMPERATURE (°C)
Δ
In general, thermal diode temperature measurements are based on the change in forward bias voltage
of a diode when operated at two different currents. This ΔV
as shown in the following equation:
The temperature measurement results are stored in the internal and external temperature registers.
These are then compared with the values stored in the high and low limit registers. Both external and
internal temperature measurements are stored in 11-bit format with the eight (8) most significant bits
stored in a high byte register and the three (3) least significant bits stored in the three (3) MSB
positions of the low byte register. All other bits of the low byte register are set to zero.
The EMC1413 and EMC1414 have two selectable temperature ranges. The default range is from 0°C
to +127°C and the temperature is represented as binary number able to report a temperature from 0°C
to +127.875°C in 0.125°C steps.
The extended range is an extended temperature range from -64°C to +191°C. The data format is a
binary number offset by 64°C. The extended range is used to measure temperature diodes with a large
known offset (such as AMD processor diodes) where the diode temperature plus the offset would be
equivalent to a temperature higher than +127°C.
Table 5.3, "EMC1413 and EMC1414 Temperature Data Format"
formats.
Temperature Monitors
Temperature Measurement Results and Data
V
BE
=
η
Table 5.3 EMC1413 and EMC1414 Temperature Data Format
kT
q
000 0000 0000
000 0000 0000
000 0000 0000
000 0000 0000
Note 5.1
000 0000 0001
000 0000 1000
010 0000 0000
010 0000 1000
011 1111 1000
011 1111 1111
011 1111 1111
Note 5.3
ln
DEFAULT RANGE 0°C TO 127°C
⎛
⎜ ⎜
⎝
I
I
HIGH
LOW
⎞
⎟ ⎟
⎠
DATASHEET
23
where:
k = Boltzmann’s constant
T = absolute temperature in Kelvin
q = electron charge
η
= diode ideality factor
BE
000 0000 0000
000 0000 0000
Note 5.2
001 1111 1000b
010 0000 0000
010 0000 0001
010 0000 1000
100 0000 0000
100 0000 1000
101 1111 1000
101 1111 1111
110 0000 0000
is proportional to absolute temperature
shows the default and extended range
EXTENDED RANGE RANGE
-64°C TO 191°C
Revision 1.37 (12-23-09)
[1]