EMC1212 SMSC Corporation, EMC1212 Datasheet - Page 8
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EMC1212
Manufacturer Part Number
EMC1212
Description
BBUS Compliant Dual Temperature Monitor
Manufacturer
SMSC Corporation
Datasheet
1.EMC1212.pdf
(13 pages)
Revision 1.1 (02-07-07)
3.2
Diode Fault or -64
-63.875
-63
-1
0
substrate
CPU
PNP
TEMPERATURE (°C)
Thermal diode temperature measurements are based on the change in forward bias voltage of a diode
when operated at two or more different currents.
As can be seen in this equation, the delta V
shows a block diagram of the temperature monitoring circuitry. The delta V
effective rate of 3.125kHz and then measured by the internal 11 bit delta sigma ADC.
The advantages of this architecture over Nyquist rate FLASH or SAR converters are superb linearity
and inherent noise immunity. The linearity can be directly attributed to the delta sigma ADC single bit
comparator while the noise immunity is achieved by the 20.75ms integration time. The input bandwidth
of the system is fs/2048, this translates to 50Hz at a 100kHz clock frequency.
The temperature data format is an offset 2’s complement with a range of -64°C to +191.875°C as
shown in
Temperature Monitor
Δ
V
BE
Table
=
Figure 3.2 Block Diagram of Temperature Monitoring
V
3.1.
BE
Table 3.1 EMC1212 Temperature Data Format
_
HIGH
Compensation
−
Circuitry
V
Beta
BE
100 0000 0000
100 0000 0001
100 0000 1000
110 1111 1000
110 0000 0000
_
LOW
DATASHEET
=
η
BBUS Compliant Dual Temperature Monitor with Beta Compensation
kT
q
BE
Resistance
BINARY
8
Correction
ln
voltage is directly proportional to temperature.
Error
⎛
⎜ ⎜
⎝
I
I
2’S COMPLEMENT FORMAT
HIGH
LOW
I
HIGH
⎞
⎟ ⎟
⎠
Sampler
Filter &
Input
I
where:
k = Boltzmann’s constant
T = absolute temperature in Kelvin
q = electron charge
η
LOW
= diode ideality factor
400h
401h
408h
6F8h
600h
BE
delta-sigma
is first sampled at an
HEX
11-bit
ADC
SMSC EMC1212
Figure 3.2
Datasheet