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參數(shù)資料
| 型號： | ASC7521A |
| 廠商： | Electronic Theatre Controls, Inc. |
| 元件分類： | 溫度/濕度傳感器 |
| 英文描述： | LOW- OLTAGE 1-WIRE DIGITAL TEMPERATURE SENSOR |
| 中文描述： | 低OLTAGE 1 - Wire數(shù)字溫度傳感器 |
| 文件頁數(shù)： | 5/18頁 |
| 文件大?。?/td> | 186K |
| 代理商： | ASC7521A |
- 5 -
Andigilog, Inc. 2006
www.andigilog.com
October 2006 - 70A05011
aSC7521A
Values that would represent temperatures below -273.15°C (0
K or absolute zero) are reserved and are not be returned
except as specifically noted.
For the aSC7521A the required resolution is 0.125°C. Bits
[2:0] will be defined but they are beyond the required
resolution. The sign bit will indicate a negative temperature
except when reporting an error condition (see
Sensor Error
Condition
).
Temperature
80°C
79.875°C
1°C
0°C
-1°C
-5°C
2’s complement representation
0001 0100 0000 0000
0001 0011 1111 1000
0000 0000 0100 0000
0000 0000 0000 0000
1111 1111 1100 0000
1111 1110 1100 0000
Table 1. Temperature Representation
Sign
Integer Temperature 0°C to 512°C
Fractional
Temperature
LSB 0.125°C
5
4
Always Zero
15
14
13
12
11
10
9
8
7
6
●
3
2
1
0
Figure 2. Temperature Reading
A to D Converter Resolution and Mapping
The mapping of the A-D converter bit values is a two’s
complement representation with the binary point between bits
5 and 6 of the 16-bit data word. Bit 15 is the sign, bits 14
through 6 are integer temperature in degrees, bits 5 down to
3 are the fractional part with 0.125°C as the LSB. The lowest
3 bits are set to zero.
Temperature Inputs
The simple temperature sensor has an internal thermal
sensor plus an external sensor using a remote diode. Both
temperature readings are internally corrected for lead
resistance and non-ideality for the thermal diode of a
Pentium 4, 65nM process (1.009 non-ideality, 4.35
lead
resistance). The range of measurement currents falls within
the Intel recommended range of 10
μ
A and 170
μ
A to
minimize the impact of Beta variation in the CPU substrate
thermal diode. Note that Pentium 4, 90 nM process is 1.011
non-ideality and series resistance of 3.33
.
If a diode connected discrete transistor is used instead of a
CPU diode, a correction must be applied to the reading to
compensate for the difference in non-ideality. A 2N3904 NPN
transistor has a non-ideality (
η
) factor of approximately 1.04.
To correct the value reported to the actual temperature use
the following formula:
T
ACTUAL
= T
REPORTED
x
η
Transistor
/ 1.009
It is recommended that the actual transistor type and
manufacturers chosen for the remote sensor be
characterized for non-ideality as part of system qualification.
Sensor Error Condition
The aSC7521A has the capability to detect and report open
or shorted external diode inputs per Sensor Error Condition.
When an error or failure condition is detected, the sensor
device must return a large negative value in response to
either the GetIntTemp() or GetExtTemp() command. In this
manner software is provided with a means to determine
whether or not the sensor is working normally and that the
data returned is good.
The aSC7521A will write one of the values from the table
below to appropriate memory locations for GetIntTemp()
and/or GetExtTemp().
The aSC7521A uses the OEM defined values of 0x8102
(open) and 0x8103 (short) rather than the generic errors
defined for codes 0x8000 to 0x8003.
Error Code
0x8000 to 0x80FF
Reserved
0x8102
Remote Diode Open
0x8103
Remote Diode Short
0x8100-0x81FF
Reserved
Description
Table 2. Error Codes
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相關(guān)代理商/技術(shù)參數(shù) |
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| ASC7521AM8 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:LOW- OLTAGE 1-WIRE DIGITAL TEMPERATURE SENSOR |
| ASC7531A | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:LOW-VOLTAGE 1-WIRE DIGITAL TEMPERATURE SENSOR AND VOLTAGE MONITOR |
| ASC7531AM10 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:LOW-VOLTAGE 1-WIRE DIGITAL TEMPERATURE SENSOR AND VOLTAGE MONITOR |
| ASC7531B | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:LOW-VOLTAGE 1-WIRE DIGITAL TEMPERATURE SENSOR AND VOLTAGE MONITOR |
| ASC7531BM10 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:LOW-VOLTAGE 1-WIRE DIGITAL TEMPERATURE SENSOR AND VOLTAGE MONITOR |
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