參數(shù)資料
型號: LMC6681
廠商: National Semiconductor Corporation
英文描述: Low Voltage, Rail-To-Rail Input and Output CMOS
中文描述: 低電壓軌至軌輸入和輸出的CMOS
文件頁數(shù): 20/24頁
文件大?。?/td> 750K
代理商: LMC6681
Filters
(Continued)
The LMC6681/2/4, with its rail-to-rail input common-mode
voltage range and high gain (120 dB typical, R
= 10 k
) is
extremely well suited for such filter applications. The
rail-to-rail input range allows for large input signals to be pro-
cessed without distortion. The high gain means that the cir-
cuit can provide filtering and gain in one stage, instead of the
typical two stage filter. This implies a reduction in cost, and
savings of space and power.
This is an illustration of the conceptual use of the LMC6681/
2/4. The selectivity of the filter can be improved by increas-
ing the order (number of poles) of the design.
Sample-and-Hold Circuits
When the “Switch” is closed during the Sample Interval,
C
charges up to the value of the input signal when the
“Switch” is open, C
retains this value as it is buffered by
the high input impedance of the LMC6681.
Errors in the “hold” voltage are caused by the input current of
the amplifier, the leakage current of the CD4066, and the
leakage current of the capacitor. While an input current of 80
fAminimizes the accumulation rate for error in this circuit, the
LMC6681’s CMRR of 82 dB allows excellent accuracy
throughout the amplifier’s rail-to-rail dynamic capture range.
Battery Monitoring Circuit
The LMC6681/2/4 has been optimized for performance at
3V, and also has guaranteed specs at 1.8V and 2.2V. In por-
table
applications,
the
R
notebook, or any other computer which the battery is power-
ing. A desired
output
voltage
manipulating the ratios of the feedback resistors. During the
charging cycle, the current flows out of the battery as shown.
While during discharge, the current is in the reverse direc-
tion. Since the current can range from a few milliamperes to
amperes, the amplifier will have to sense a signal below
ground during the discharge cycle. At 3V, the LMC6681/2/4
can accept a signal up to 300 mV below ground. The
common-mode voltage range of the LMC6681/2/4, which ex-
tends beyond both rails, is thus a very useful feature in this
application.
A typical offset voltage of 0.5 mV, and CMRR of 82 dB main-
tain accuracy in the circuit output, while the rail-to-rail output
performance allows for a maximum signal range.
represents
the
laptop/
can
be
achieved
by
DS012042-34
FIGURE 25. Sample-and-Hold Application
DS012042-37
FIGURE 26. Circuit Used to Sense Charging
DS012042-38
FIGURE 27. Circuit Used to Sense Discharging
www.national.com
20
相關(guān)PDF資料
PDF描述
LMC6681AIM Low Voltage, Rail-To-Rail Input and Output CMOS
LMC6681AIMX Low Voltage, Rail-To-Rail Input and Output CMOS
LMC6681AIN Low Voltage, Rail-To-Rail Input and Output CMOS
LMC6681BIM Low Voltage, Rail-To-Rail Input and Output CMOS
LMC6681BIN Low Voltage, Rail-To-Rail Input and Output CMOS
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LMC6681AIM 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Texas Instruments 功能描述:
LMC6681AIMX 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Low Voltage, Rail-To-Rail Input and Output CMOS
LMC6681AIN 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Low Voltage, Rail-To-Rail Input and Output CMOS
LMC6681B1MX 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Low Voltage, Rail-To-Rail Input and Output CMOS
LMC6681BIM 制造商:Rochester Electronics LLC 功能描述:- Bulk