- 您現(xiàn)在的位置：買(mǎi)賣(mài)IC網(wǎng) > PDF目錄358885 > LMV791 (National Semiconductor Corporation) 17 MHz, Low Noise, CMOS Input, 1.8V Operational Amplifier PDF資料下載
參數(shù)資料
| 型號(hào)： | LMV791 |
| 廠商： | National Semiconductor Corporation |
| 元件分類(lèi)： | 運(yùn)算放大器 |
| 英文描述： | 17 MHz, Low Noise, CMOS Input, 1.8V Operational Amplifier |
| 中文描述： | 17兆赫，低噪聲，CMOS輸入，1.8V的運(yùn)算放大器 |
| 文件頁(yè)數(shù)： | 12/16頁(yè) |
| 文件大?。?/td> | 1005K |
| 代理商： | LMV791 |
第1頁(yè)第2頁(yè)第3頁(yè)第4頁(yè)第5頁(yè)第6頁(yè)第7頁(yè)第8頁(yè)第9頁(yè)第10頁(yè)第11頁(yè)當(dāng)前第12頁(yè)第13頁(yè)第14頁(yè)第15頁(yè)第16頁(yè)
Application Notes
ADVANTAGES OF THE LMV791
Wide Bandwidth at Low Supply Current
The LMV791 is a high performance op amp that provides a
unity gain bandwidth of 17 MHz while drawing a low supply
current of merely 1.15 mA. This makes it ideal for providing
wideband amplification in portable applications. The enable
and shutdown feature can also be used to design more
power efficient systems and obtain wider bandwidth and
better performance while using less power.
Low Input Referred Noise and Low Input Bias Current
The LMV791 has a very low input referred voltage noise
density (5.8 nV/
at 1 kHz).ACMOS input stage ensures
a small input bias current (100 fA) and, hence, the input
referred current noise is very low (0.01 pA/
very helpful in maintaining signal fidelity, and makes the
LMV791 ideal for audio and sensor based applications.
). This is
Low Supply Voltage
LMV791 is guaranteed to perform at 2.5V and 5V supply.
The LMV791 is guaranteed to be operational at all supply
voltages between 2V and 5.5V, for ambient temperatures
ranging from 40C to 125C, thus utilizing the entire battery
lifetime. The LMV791 is also guaranteed to be operational at
1.8V supply voltage, for temperatures between 0C and
125C. This makes the LMV791 ideal for usage in low-
voltage commercial applications.
RRO and Ground Sensing
Rail-to-rail output swing provides maximum possible dy-
namic range at the output. This is particularly important
when operating at low supply voltages. An innovative posi-
tive feedback scheme is used to boost the current drive
capability of the output stage. This allows the LMV791 to
source more than 40 mA of current at 1.8V supply. This also
limits the performance of the LMV791 as a comparator, and
hence the usage of LMV791 in an open-loop configuration is
not recommended. The input common-mode range includes
the negative supply rail which allows direct sensing at
ground in single supply operation.
Enable and Shutdown Features
The LMV791 is ideal for battery powered systems. With a
low supply current of 1.15 mA and a shutdown current
typically less than 1 μA, it allows the designer to maximize
battery life. The enable pin of the LMV791 allows the op amp
to be turned off and reduce its supply current to less than 1
uA. To power on the op amp the enable pin should be higher
than V
+
- 0.5V, where V
+
is the positive supply. To disable the
op amp, the enable pin should be lesser than V
+ 0.5V,
where V
is the negative supply.
Small Size
The small footprint of the LMV791 package saves space on
printed circuit boards, and enables the design of smaller
electronic products, such as cellular phones, pagers, or
other portable systems. Signals can pick up noise between
the signal source and the amplifier. By using a physically
smaller amplifier package, the LMV791 can be placed closer
to the signal source, reducing noise pickup and increasing
signal integrity.
CAPACITIVE LOAD TOLERANCE
The LMV791 can directly drive 120 pF in unity-gain without
oscillation. The unity-gain follower is the most sensitive con-
figuration to capacitive loading. Direct capacitive loading
reduces the phase margin of amplifiers. The combination of
the amplifier’s output impedance and the capacitive load
induces phase lag. This results in either an underdamped
pulse response or oscillation. To drive a heavier capacitive
load, the circuit in
Figure 1
can be used.
In
Figure 1
, the isolation resistor R
ISO
and the load capacitor
C
L
form a pole to increase stability by adding more phase
margin to the overall system. The desired performance de-
pends on the value of R
ISO
. The bigger the R
ISO
resistor
value, the more stable V
OUT
will be. Increased R
ISO
would,
however, result in a reduced output swing and short circuit
current.
INPUT CAPACITANCE AND FEEDBACK CIRCUIT
ELEMENTS
The LMV791 has a very low input bias current (50 fA) and a
low 1/f noise corner frequency (400 Hz), which makes it ideal
for sensor applications. However, to obtain this performance
a large CMOS input stage is used, which adds to the input
capacitance. Though this does not affect the DC and low
frequency performance, at higher frequencies the input ca-
pacitance interacts with the input and the feedback imped-
ances to create a pole, which results in lower phase margin
and gain peaking. This can be controlled by being selective
in the use of feedback resistors, as well as by using a
feedback capacitance. For example, in the non-inverting
amplifier shown in
Figure 2
, if C
IN
and C
F
are ignored and
the open loop gain of the op amp is considered infinite then
the gain of the circuit is R
/R
.An op amp, however, usually
has a dominant pole, which causes its gain to drop with
frequency. Hence, this gain is only valid for DC and low
frequency. To understand the effect of the input capacitance
coupled with the non-ideal gain of the op amp, the circuit
needs to be analyzed in the frequency domain using a
Laplace transform.
20116861
FIGURE 1.
L
www.national.com
12
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| 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 |
| LMV822DGK | LOW-VOLTAGE RAIL-TO-RAIL OUTPUT OPERATIONAL AMPLIFIERS |
| LMV822M | Low Voltage, Low Power, R-to-R Output, 5 MHz Op Amps |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LMV791MK | 功能描述:運(yùn)算放大器 - 運(yùn)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(bǔ)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(fēng)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 |
| LMV791MK/NOPB | 功能描述:運(yùn)算放大器 - 運(yùn)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(bǔ)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(fēng)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 |
| LMV791MKX | 功能描述:運(yùn)算放大器 - 運(yùn)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(bǔ)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(fēng)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 |
| LMV791MKX/NOPB | 功能描述:運(yùn)算放大器 - 運(yùn)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(bǔ)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(fēng)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 |
| LMV792 | 制造商:NSC 制造商全稱(chēng):National Semiconductor 功能描述:17 MHz, Low Noise, CMOS Input, 1.8V Operational Amplifiers |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。