- 您現在的位置：買賣IC網 > PDF目錄373995 > ADM1020AR-REEL7 (ANALOG DEVICES INC) 8-Lead, Low-Cost, System Temperature Monitor PDF資料下載
參數資料
| 型號： | ADM1020AR-REEL7 |
| 廠商： | ANALOG DEVICES INC |
| 元件分類： | 模擬信號調理 |
| 英文描述： | 8-Lead, Low-Cost, System Temperature Monitor |
| 中文描述： | SPECIALTY ANALOG CIRCUIT, PDSO8 |
| 封裝： | SOIC-8 |
| 文件頁數： | 11/12頁 |
| 文件大小： | 132K |
| 代理商： | ADM1020AR-REEL7 |
REV. 0
ADM1020
–11–
LAYOUT CONSIDERATIONS
Digital boards can be electrically noisy environments, and the
ADM1020 is measuring very small voltages from the remote
sensor, so care must be taken to minimize noise induced at the
sensor inputs. The following precautions should be taken:
1. Place the ADM1020 as close as possible to the remote sens-
ing diode. Provided that the worst noise sources such as clock
generators, data/address buses and CRTs are avoided, this
distance can be 4 to 8 inches.
2. Route the D+ and D– tracks close together, in parallel, with
grounded guard tracks on each side. Provide a ground plane
under the tracks if possible.
3. Use wide tracks to minimize inductance and reduce noise
pickup. 10 mil track minimum width and spacing is
recommended.
10mil
GND
D+
D–
GND
10mil
10mil
10mil
10mil
10mil
10mil
Figure 14. Arrangement of Signal Tracks
4. Try to minimize the number of copper/solder joints, which
can cause thermocouple effects. Where copper/solder joints
are used, make sure that they are in both the D+ and D–
path and at the same temperature.
Thermocouple effects should not be should not be a major
problem as 1
°
C corresponds to about 200 mV, and thermo-
couple voltages are about 3 mV/
°
C of temperature difference.
Unless there are two thermocouples with a big temperature
differential between them, thermocouple voltages should be
much less than 200 mV.
5. Place a 0.1
μ
F bypass capacitor close to the V
DD
pin and
2200 pF input filter capacitors across D+, D– close to the
ADM1020.
6. If the distance to the remote sensor is more than 8 inches, the
use of twisted pair cable is recommended. This will work up
to about 6 to 12 feet.
7. For really long distances (up to 100 feet) use shielded twisted
pair such as Belden #8451 microphone cable. Connect the
twisted pair to D+ and D– and the shield to GND close to
the ADM1020. Leave the remote end of the shield uncon-
nected to avoid ground loops.
Because the measurement technique uses switched current
sources, excessive cable and/or filter capacitance can affect the
measurement. When using long cables, the filter capacitor may
be reduced or removed.
Cable resistance can also introduce errors. 1
series resistance
introduces about 0.5
°
C error.
APPLICATION CIRCUITS
Figure 15 shows a typical application circuit for the ADM1020,
using a discrete sensor transistor connected via a shielded,
twisted pair cable. The pull-ups on SCLK, SDATA and
ALERT
are required only if they are not already provided elsewhere in
the system.
SCLK
SDATA
ALERT
ADD
GND
D+
D–
0.1
m
F
10k
V
+3.3V
SET TO REQUIRED
ADDRESS
C1*
SHIELD
2N3904
*C1 IS OPTIONAL
ADM1020
V
DD
10k
V
10k
V
TO
PIIX4
CHIP
IN
OUT
I/O
Figure 15. Typical ADM1020 Application Circuit
相關PDF資料 |
PDF描述 |
|---|---|
| ADM1021A | Low-Cost Microprocessor System Temperature Monitor |
| ADM1021AARQ | Low-Cost Microprocessor System Temperature Monitor |
| ADM1021 | Low Cost Microprocessor System Temperature Monitor |
| ADM1021ARQ | Low Cost Microprocessor System Temperature Monitor |
| ADM1022 | Low-Cost PC Temperature Monitor and Fan Control ASIC |
相關代理商/技術參數 |
參數描述 |
|---|---|
| ADM1021 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Low Cost Microprocessor System Temperature Monitor |
| ADM102-11/12VDC | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC |
| ADM102-11/24VDC | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC |
| ADM102-11/48VDC | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC |
| ADM1021A | 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:Low Cost Microprocessor System Temperature Monitor Microcomputer |
發布緊急采購，3分鐘左右您將得到回復。