參數(shù)資料
型號: G781
廠商: Electronic Theatre Controls, Inc.
元件分類: 溫度/濕度傳感器
英文描述: 【1∑C Remote and Local Temperature Sensor with SMBus Serial Interface
中文描述: 【1ΣC遠程和本地溫度傳感器,帶有SMBus串行接口
文件頁數(shù): 6/14頁
文件大?。?/td> 342K
代理商: G781
Ver: 1.0
Oct 02, 2002
TEL: 886-3-5788833
http://www.gmt.com.tw
6
Global Mixed-mode Technology Inc.
G781
Do not route the DXP-DXN lines next to the deflection
coils of a CRT. Also, do not route the traces across a
fast memory bus, which can easily introduce +30°C
error, even with good filtering, Otherwise, most noise
sources are fairly benign.
Route the DXP and DXN traces in parallel and in close
proximity to each other, away from any high-voltage
traces such as +12V
DC
. Leakage currents from PC
board contamination must be dealt with carefully,
since a 10M
leakage path from DXP to ground
causes about +1°C error.
Connect guard traces to GND on either side of the
DXP-DXN traces (Figure 2). With guard traces in place,
routing near high-voltage traces is no longer an issue.
Route through as few vias and crossunders as
possible to minimize copper/solder thermocouple ef-
fects.
When introducing a thermocouple, make sure that
both the DXP and the DXN paths have matching
thermocouples. In general, PC board-induced ther-
mocouples are not a serious problem, A copper-solder
thermocouple exhibits 3μV/°C, and it takes about
240μV of voltage error at DXP-DXN to cause a +1°C
measurement error. So, most parasitic thermocouple
errors are swamped out.
Use wide traces. Narrow ones are more inductive and
tend to pick up radiated noise. The 10 mil widths and
spacing recommended on Figure 2 aren’t absolutely
necessary (as they offer only a minor improvement in
leakage and noise), but try to use them where practi-
cal.
Keep in mind that copper can’t be used as an EMI
shield, and only ferrous materials such as steel work
will. Placing a copper ground plane between the
DXP-DXN traces and traces carrying high-frequency
noise signals does not help reduce EMI.
PC Board Layout Checklist
Place the G781 close to a remote diode.
Keep traces away from high voltages (+12V bus).
Keep traces away from fast data buses and CRTs.
Use recommended trace widths and spacing.
Place a ground plane under the traces
Use guard traces flanking DXP and DXN and con
necting to GND.
Place the noise filter and the 0.1μF VCC bypass
capacitors close to the G781.
Figure 2. Recommended DXP/DXN PC Traces
Twisted Pair and Shielded Cables
For remote-sensor distances longer than 8 in., or in
particularly noisy environments, a twisted pair is rec-
ommended. Its practical length is 6 feet to 12feet (typi
cal) before noise becomes a problem, as tested in a
noisy electronics laboratory. For longer distances, the
best solution is a shielded twisted pair like that used
for audio microphones. Connect the twisted pair to
DXP and DXN and the shield to GND, and leave the
shield’s remote end unterminated.
Excess capacitance at DX_limits practical remote sen-
sor distances (see Typical Operating Characteristics),
For very long cable runs, the cable’s parasitic capaci-
tance often provides noise filtering, so the 2200pF ca-
pacitor can often be removed or reduced in value. Ca-
ble resistance also affects remote-sensor accuracy; 1
series resistance introduces about + 0.6°C error.
Low-Power Standby Mode
Standby mode disables the ADC and reduces the
supply-current drain to about 10μA. Enter standby
mode by forcing high to the
RUN
/STOP bit in the con-
figuration byte register. Software standby mode be-
haves such that all data is retained in memory, and the
SMB interface is alive and listening for reads and
writes.
Software standby mode is not a shutdown mode. With
activity on the SMBus, extra supply current is drawn
(see Typical Operating Characteristics). In software
standby mode, the G781 can be forced to perform A/D
conversions via the one-shot command, despite the
RUN
/STOP bit being high.
GND
DXP
DXN
GND
10 MILS
MINIMUM
10 MILS
10 MILS
10 MILS
相關(guān)PDF資料
PDF描述
G8912B Aluminum Snap-In Capacitor; Capacitance: 3300uF; Voltage: 63V; Case Size: 22x45 mm; Packaging: Bulk
G8912BC Aluminum Snap-In Capacitor; Capacitance: 3900uF; Voltage: 63V; Case Size: 30x35 mm; Packaging: Bulk
G8912BCI Aluminum Snap-In Capacitor; Capacitance: 4700uF; Voltage: 63V; Case Size: 25x50 mm; Packaging: Bulk
G8912BD Aluminum Snap-In Capacitor; Capacitance: 4700uF; Voltage: 63V; Case Size: 30x40 mm; Packaging: Bulk
G8912BDI Aluminum Snap-In Capacitor; Capacitance: 6800uF; Voltage: 63V; Case Size: 30x50 mm; Packaging: Bulk
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
G7816E 制造商:OMRON AUTOMATION AND SAFETY 功能描述:SHORTING BAR-G70A-16A
G78-16-E 功能描述:SHORTING BAR-G70A-16A RoHS:是 類別:工業(yè)控制,儀表 >> 配件 系列:* 標準包裝:1 系列:Aero-Motive® 130117 附件類型:拖車帶 適用于相關(guān)產(chǎn)品:標準盒式跟蹤系統(tǒng) 其它名稱:WM6183
G78-16-P2RF-E 制造商:OMRON Electronic Components LLC 功能描述: 制造商:Omron Americas 功能描述:BUSBAR 16WAY 制造商:Omron Americas 功能描述:BUSBAR, 16WAY 制造商:Omron Corporation 功能描述:BUSBAR, 16WAY, Accessory Type:Jumper, For Use With:G70A Series I/O Blocks, No. o 制造商:Omron Corporation 功能描述:Busbar for G2R-SNI power relay 制造商:OK Industries 功能描述:COMMON BUSBAR
G784B 制造商:IDEA 制造商全稱:IDEA 功能描述:T-1, (3-mm) Round, Bi-level PCB Mount LED Indicator
G7853-245-1.5B 功能描述:環(huán)形MIL規(guī)格后蓋 RoHS:否 制造商:Amphenol PCD MIL 類型:MIL-DTL-38999 III, IV 系列:AS85049 產(chǎn)品類型:Environmental EMI/RFI Backshells 外殼類型:Straight 外殼大小:18 外殼材質(zhì):Aluminum Alloy