參數(shù)資料
型號: LMC6081
廠商: National Semiconductor Corporation
英文描述: CAP 0.01UF 50V 10% X7R SMD-0603 TR-7-PA NI-BAR/SN ROHS
中文描述: 精密CMOS單運算放大器
文件頁數(shù): 8/12頁
文件大?。?/td> 304K
代理商: LMC6081
Applications Hints
(Continued)
ure 4 To have a significant effect, guard rings should be
placed on both the top and bottom of the PC board. This PC
foil must then be connected to a voltage which is at the same
voltage as the amplifier inputs, since no leakage current can
flow between two points at the same potential. For example,
a PC board trace-to-pad resistance of 10
12
, which is nor-
mally considered a very large resistance, could leak 5 pA if
the trace were a 5V bus adjacent to the pad of the input. This
would cause a 100 times degradation from the LMC6081’s
actual performance. However, if a guard ring is held within
5 mV of the inputs, then even a resistance of 10
11
would
cause only 0.05 pA of leakage current. See Figure 5 for typi-
cal connections of guard rings for standard op-amp
configurations.
The designer should be aware that when it is inappropriate
to lay out a PC board for the sake of just a few circuits, there
is another technique which is even better than a guard ring
on a PC board: Don’t insert the amplifier’s input pin into the
board at all, but bend it up in the air and use only air as an in-
sulator. Air is an excellent insulator. In this case you may
have to forego some of the advantages of PC board con-
struction, but the advantages are sometimes well worth the
effort
of
using
point-to-point
See Figure 6
up-in-the-air
wiring.
Latchup
CMOS devices tend to be susceptible to latchup due to their
internal parasitic SCR effects. The (I/O) input and output pins
look similar to the gate of the SCR. There is a minimum cur-
DS011423-6
FIGURE 4. Example of Guard Ring in P.C. Board
Layout
DS011423-7
Inverting Amplifier
DS011423-8
Non-Inverting Amplifier
DS011423-9
Follower
FIGURE 5. Typical Connections of Guard Rings
DS011423-10
(Input pins are lifted out of PC board and soldered directly to components.
FIGURE 6. Air Wiring
www.national.com
8
相關(guān)PDF資料
PDF描述
LMC6081AIM Precision CMOS Single Operational Amplifier
LMC6081AIN Precision CMOS Single Operational Amplifier
LMC6081AMN Precision CMOS Single Operational Amplifier
LMC6081IM Precision CMOS Single Operational Amplifier
LMC6081IN Precision CMOS Single Operational Amplifier
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LMC6081AIM 制造商:Texas Instruments 功能描述:IC OP AMP CMOS SMD 6081 SOIC8
LMC6081AIM/NOPB 功能描述:運算放大器 - 運放 Prec CMOS Sgl Op Amp RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比(最小值):63 dB 輸入補償電壓:1 mV 輸入偏流(最大值):10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風格:SMD/SMT 封裝 / 箱體:QFN-16 轉(zhuǎn)換速度:0.89 V/us 關(guān)閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel
LMC6081AIMX 功能描述:運算放大器 - 運放 RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比(最小值):63 dB 輸入補償電壓:1 mV 輸入偏流(最大值):10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風格:SMD/SMT 封裝 / 箱體:QFN-16 轉(zhuǎn)換速度:0.89 V/us 關(guān)閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel
LMC6081AIMX/NOPB 功能描述:運算放大器 - 運放 RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比(最小值):63 dB 輸入補償電壓:1 mV 輸入偏流(最大值):10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風格:SMD/SMT 封裝 / 箱體:QFN-16 轉(zhuǎn)換速度:0.89 V/us 關(guān)閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel