- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄358885 > LMV771MG (NATIONAL SEMICONDUCTOR CORP) Single/Dual/Quad, Low Offset, Low Noise, RRO Operational Amplifiers PDF資料下載
參數(shù)資料
| 型號： | LMV771MG |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 運算放大器 |
| 英文描述： | Single/Dual/Quad, Low Offset, Low Noise, RRO Operational Amplifiers |
| 中文描述： | OP-AMP, 1000 uV OFFSET-MAX, 3.5 MHz BAND WIDTH, PDSO5 |
| 封裝： | SC-70, 5 PIN |
| 文件頁數(shù)： | 13/21頁 |
| 文件大?。?/td> | 844K |
| 代理商： | LMV771MG |
Application Note
LMV771/LMV772/LMV774
The LMV771/LMV772/LMV774 is a family of precision am-
plifiers with very low noise and ultra low offset voltage.
LMV771/LMV772/LMV774’s extended temperature range of
40C to 125C enables the user to design this family of
products in a variety of applications including automotive.
LMV771 has a maximum offset voltage of 1mV over the
extended temperature range. This makes LMV771 ideal for
applications where precision is of importance.
LMV772/LMV774 have a maximum offset voltage of 1mV at
room temperature and 1.2mV over the extended tempera-
ture range of 40C to 125C. Care must be given when
LMV772/LMV774 are designed in applications with heavy
loads under extreme temperature conditions. As indicated in
the DC tables, the LMV772/LMV774’s gain and output swing
may be reduced at temperatures between 85C and 125C
with loads heavier than 2k
.
INSTRUMENTATION AMPLIFIER
Measurement of very small signals with an amplifier requires
close attention to the input impedance of the amplifier, gain
of the overall signal on the inputs, and the gain on each input
since we are only interested in the difference of the two
inputs and the common signal is considered noise. A classic
solution is an instrumentation amplifier. Instrumentation am-
plifiers have a finite, accurate, and stable gain. Also they
have extremely high input impedances and very low output
impedances. Finally they have an extremely high CMRR so
that the amplifier can only respond to the differential signal.
A typical instrumentation amplifier is shown in
Figure 1
.
There are two stages in this amplifier. The last stage, output
stage, is a differential amplifier. In an ideal case the two
amplifiers of the first stage, input stage, would be set up as
buffers to isolate the inputs. However they cannot be con-
nected as followers because of real amplifiers mismatch.
That is why there is a balancing resistor between the two.
The product of the two stages of the gain will give the gain of
the instrumentation amplifier. Ideally, the CMRR should be
infinity. However the output stage has a small non-zero
common mode gain which results from resistor mismatch.
In the input stage of the circuit, current is the same across all
resistors. This is due to the high input impedance and low
input bias current of the LMV771. With the node equations
we have:
(1)
By Ohm’s Law:
(2)
However:
(3)
So we have:
(4)
Now looking at the output of the instrumentation amplifier:
(5)
Substituting from equation 4:
(6)
This shows the gain of the instrumentation amplifier to be:
K(2a+1)
Typical values for this circuit can be obtained by setting: a =
12 and K= 4. This results in an overall gain of 100.
Figure 2
shows typical CMRR characteristics of this Instru-
mentation amplifier over frequency. Three LMV771 amplifi-
ers are used along with 1%resistors to minimize resistor
mismatch. Resistors used to build the circuit are: R
=
21.6k
, R
= 1.8k
, R
= 2.5k
with K = 40 and a = 12.
This results in an overall gain of 1000, K(2a+1) = 1000.
20039636
FIGURE 1.
L
www.national.com
13
相關PDF資料 |
PDF描述 |
|---|---|
| LMV771MGX | Single/Dual/Quad, Low Offset, Low Noise, RRO Operational Amplifiers |
| LMV791 | 17 MHz, Low Noise, CMOS Input, 1.8V Operational Amplifier |
| LMV791MK | 17 MHz, Low Noise, CMOS Input, 1.8V Operational Amplifier |
| LMV791MKX | 17 MHz, Low Noise, CMOS Input, 1.8V Operational Amplifier |
| LMV8172 | Vertical Deflection Output Amplifier |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LMV771MG | 制造商:Texas Instruments 功能描述:OP AMP, LOW NOISE, SMD, SC70-5, 771 制造商:Texas Instruments 功能描述:OP AMP, LOW NOISE, SMD, SC70-5, 771; Op Amp Type:Low Noise; No. of Amplifiers:1; Slew Rate:1.4V/s; Supply Voltage Range:2.7V to 5.5V; Amplifier Case Style:SC-70; No. of Pins:5; Bandwidth:3.5MHz; Operating Temperature Min:-40C; ;RoHS Compliant: Yes |
| LMV771MG/NOPB | 功能描述:運算放大器 - 運放 Low Noise,Prec Op Amp In 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 關閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel |
| LMV771MGX | 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 關閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel |
| LMV771MGX/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 關閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel |
| LMV772 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Single/Dual/Quad, Low Offset, Low Noise, RRO Operational Amplifiers |
發(fā)布緊急采購，3分鐘左右您將得到回復。