參數(shù)資料
型號(hào)： OPA843IDR
元件分類： 運(yùn)算放大器
英文描述： Wideband, Low Distortion, Medium Gain, Voltage-Feedback OPERATIONAL AMPLIFIER
中文描述： 寬帶，低失真，中等增益，電壓反饋運(yùn)算放大器
文件頁(yè)數(shù)： 12/22頁(yè)
文件大小： 377K
代理商： OPA843IDR
OPA843
SBOS268A
12
www.ti.com
WIDEBAND INVERTING SUMMING AMPLIFIER
One common application for a wideband op amp like the
OPA843 is to sum a number of signal sources together.
Figure 5 shows the inverting summing configuration that is
most often used. This circuit offers the benefit that each input
sees an input impedance set only by its individual input
resistor, since the summing junction (inverting op amp node)
is a virtual ground. Each input is non-interactive with every
other. However, the bandwidth from any input to the summed
output is set by the op amp noise gain (NG), which is equal
to the noninverting voltage gain. Therefore, each inverting
channel may have a low gain to the output (like the
–
1 shown
in Figure 5); this noise gain will set the frequency response
and the loop stability. The noninverting gain for Figure 5 is
equal to +5, which will give a 260MHz bandwidth at a gain of
–
1 for each of the input signals.
transition from a unity gain receiver at lower frequencies
(through the R
5
path) to a gain of 20dB (10V/V) through the
R
1
path at higher frequencies. The component values have
been selected to set the peak gain at approximately 30MHz.
A unique feature for this circuit is an independent tune on the
width of the peaking (Q of the response) by adjusting R
G
.
See Figure 9 for the effect of adjusting R
G
over the range of
20
to 100
.
DESIGN-IN TOOLS
DEMONSTRATION BOARDS
Two PC boards are available to assist in the initial evaluation
of circuit performance using the OPA843 in its two package
styles. Both of these are available, free, as an unpopulated PC
board delivered with descriptive documentation. The summary
information for these boards is shown in the table below.
2nd-Order Filter Topology
High-speed amplifiers like the OPA843 are good choices for
2nd-order filter building blocks as part of ADC driver chan-
nels. These can provide noise bandlimiting to improve the
SNR for the amplifier/converter combination. The circuit of
Figure 6 shows an example of a 10MHz Butterworth low-
pass filter where the amplifier provides a low frequency gain
of 5 and a 2nd-order cutoff at 10MHz. The resistor values
have been adjusted slightly to account for the amplifier
bandwidth. Figure 7 shows the small-signal frequency re-
sponse for this filter.
EQUALIZING FILTER APPLICATION
In sensor receiver applications, where the pickup is a sensor
or cable giving a bandlimited frequency response, an equal-
izing filter can sometimes be used to extend the useable
frequency range for the sensor. This is done mathematically
by taking the inverse of the rolloff transfer function and
implementing that as the amplifier frequency response. See
Figure 8 for one example of a wideband equalizer where two
stages of the OPA843 are used. This example is set to
Contact your sales representative or go to the TI web site
(www.ti.com) to request evaluation boards.
R
F
402
OPA843
+5V
–
5V
0.1
μ
F
402
81.8
V
O
=
–
(V
1
+ V
2
+ V
3
+ V
4
)
V
1
402
V
2
402
V
3
402
V
4
Power-supply decoupling not shown.
FIGURE 5. Wideband Inverting Summing Amplifier.
OPA843
150
100pF
61
0
Source
100
402
220pF
V
I
V
O
Frequency (MHz)
10MHz Low-Pass Filter
100k
1M
10M
100M
G
15
12
9
6
3
0
–
3
–
6
–
9
–
12
–
15
FIGURE 6. 10MHz Butterworth Low-Pass Filter.
FIGURE 7. Frequency Response for Figure 6.
LITERATURE
REQUEST
NUMBER
BOARD
PRODUCT
PACKAGE
PART NUMBER
OPA843U
OPA843N
SO-8
SOT23-5
DEM-OPA68xU
DEM-OPA6xx
SBOU010
SBOU009
相關(guān)PDF資料
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
OPA843IDRG4 功能描述:高速運(yùn)算放大器 Wideband Lo-Distort Med Gain Vltg Feedbk RoHS:否 制造商:Texas Instruments 通道數(shù)量:1 電壓增益 dB:116 dB 輸入補(bǔ)償電壓:0.5 mV 轉(zhuǎn)換速度:55 V/us 工作電源電壓:36 V 電源電流:7.5 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube
OPA846 制造商:TI 制造商全稱:Texas Instruments 功能描述:Wideband, Low-Noise, Voltage-Feedback OPERATIONAL AMPLIFIER
OPA846ID 功能描述:高速運(yùn)算放大器 Wideband Low Noise Voltage Feedback RoHS:否 制造商:Texas Instruments 通道數(shù)量:1 電壓增益 dB:116 dB 輸入補(bǔ)償電壓:0.5 mV 轉(zhuǎn)換速度:55 V/us 工作電源電壓:36 V 電源電流:7.5 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube
OPA846ID 制造商:Texas Instruments 功能描述:OP AMP WIDEBAND VFB SOIC8 846
OPA846IDBVR 功能描述:高速運(yùn)算放大器 Wideband Low Noise Voltage Feedback RoHS:否 制造商:Texas Instruments 通道數(shù)量:1 電壓增益 dB:116 dB 輸入補(bǔ)償電壓:0.5 mV 轉(zhuǎn)換速度:55 V/us 工作電源電壓:36 V 電源電流:7.5 mA 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube
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