- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄383692 > OPA4684 Wideband, Low-Power, Current Feedback Operational Amplifier PDF資料下載
參數(shù)資料
| 型號： | OPA4684 |
| 英文描述： | Wideband, Low-Power, Current Feedback Operational Amplifier |
| 中文描述： | 寬帶，低功耗，電流反饋運算放大器 |
| 文件頁數(shù)： | 14/26頁 |
| 文件大?。?/td> | 455K |
| 代理商： | OPA4684 |
OPA4684
SBOS240B
14
www.ti.com
This approach provides for a source termination impedance
that is independent of the signal gain. For instance, simple
differential filters may be included in the signal path right up
to the noninverting inputs without interacting with the ampli-
fier gain. The differential signal gain for the circuit of
Figure 5 is:
V
O
/V
I
= A
D
= 1 + 2
R
F
/R
G
Since the OPA4684 is a CFB
PLUS
amplifier, its bandwidth is
principally controlled with the feedback resistor value; Figure 5
shows the recommended value of 800
. However, the gain
may be adjusted with considerable freedom using just the R
G
resistor. In fact, R
G
may be a reactive network providing a
very isolated shaping to the differential frequency response.
Since the inverting inputs of the OPA4684 are very low
impedance closed-loop buffer outputs, the R
G
element does
not interact with the amplifier
’
s bandwidth
—
wide ranges of
resistor values and/or filter elements may be inserted here
with minimal amplifier bandwidth interaction.
Various combinations of single-supply or AC-coupled gains
can also be delivered using the basic circuit of Figure 5.
Common-mode bias voltages on the two noninverting inputs
pass on to the output with a gain of 1 since an equal DC
voltage at each inverting node creates no current through
R
G
, giving that voltage a common-mode gain of 1 to the
output.
Figure 6 shows a differential I/O stage configured as an
inverting amplifier. In this case, the gain resistors (R
G
)
become the input resistance for the source. This provides a
better noise performance than the noninverting configuration
but does limit the flexibility in setting the input impedance
separately from the gain.
The two noninverting inputs provide an easy common-mode
control input. This is particularly useful if the source is AC-
coupled through either blocking caps or a transformer. In
either case, the common-mode input voltages on the two
noninverting inputs again have a gain of 1 to the output pins,
giving an easy common-mode control for single-supply op-
eration. The OPA4684 used in this configuration does con-
strain the feedback to the 800
region for best frequency
response. With R
F
fixed, the input resistors may be adjusted
to the desired gain but will also be changing the input
impedance as well. The differential gain for this circuit is:
V
O
/V
I
=
–
R
F
/R
G
LOW-POWER VIDEO LINE DRIVER APPLICATIONS
For low-power, video line driving, the OPA4684 provides the
output current and linearity to support 4 channels of either
single video lines, or up to 4 video lines in parallel on each
output. Figure 7 shows a typical
±
5V supply video line driver
application where only one channel is shown and only a
single line is being driven. The improved 2nd-harmonic
distortion of the CFB
PLUS
architecture, along with the
OPA684
’
s high output current and voltage, gives exceptional
differential gain and phase performance for a low-power
solution. As the Typical Characteristics show, a single video
load shows a dG/dP of 0.04%/0.02
°
. Multiple loads may be
driven on each output, with minimal x-talk, while the dG/dP
is still < 0.1%/0.1
°
for up to 4 parallel video loads.
R
F
800
R
F
800
R
G
R
G
1/4
OPA4684
+V
CC
–
V
CC
V
CM
V
CM
V
O
1/4
OPA4684
V
I
FIGURE 6. Inverting Differential I/O Amplifier.
800
1/4
OPA4684
+5V
–
5V
75
75
800
75
Load
Supply decoupling not shown.
Coax
VIDEO
IN
DC-COUPLED SINGLE-TO-DIFFERENTIAL CONVERSION
The previous differential output circuits were set up to
receive a differential input as well as provide a differential
output. Figure 8 shows one way to provide a single to
differential conversion, with DC coupling, and independent
output common-mode control using a quad op amp.
The circuit of Figure 8 provides several useful features for
isolating the input signal from the final outputs. Using the first
amplifier as a simple noninverting stage gives an indepen-
dent adjustment on R
I
(to set the source loading) while the
gain can be easily adjusting in this stage using the R
G
resistor. Bandwidth is relatively independent of gain setting
in the OPA4684. The next stage allows a separate output
FIGURE 7. Gain of +2 Video Cable Driver.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| OPA4684IPWR | Quad, Low-Power, Current-Feedback OPERATIONAL AMPLIFIER |
| OPA4684IPWT | Quad, Low-Power, Current-Feedback OPERATIONAL AMPLIFIER |
| OPA4684IDR | Quad, Low-Power, Current-Feedback OPERATIONAL AMPLIFIER |
| OPA4705 | Low-Cost, CMOS, Rail-to-Rail, I/O OPERATIONAL AMPLIFIERS |
| OPA705 | Low-Cost, CMOS, Rail-to-Rail, I/O OPERATIONAL AMPLIFIERS |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| OPA4684ID | 功能描述:高速運算放大器 Quad Low-Power Current Feedback RoHS:否 制造商:Texas Instruments 通道數(shù)量:1 電壓增益 dB:116 dB 輸入補償電壓: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 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
| OPA4684IDBW | 制造商:TI 制造商全稱:Texas Instruments 功能描述:QUAD LOW-POWER CURRENT-FEEDBACK OPERATIONAL AMPLIFIER |
| OPA4684IDG4 | 功能描述:高速運算放大器 Quad Low-Power Current Feedback RoHS:否 制造商:Texas Instruments 通道數(shù)量:1 電壓增益 dB:116 dB 輸入補償電壓: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 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
| OPA4684IDR | 功能描述:高速運算放大器 Quad Low-Power Current Feedback RoHS:否 制造商:Texas Instruments 通道數(shù)量:1 電壓增益 dB:116 dB 輸入補償電壓: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 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
| OPA4684IDRG4 | 功能描述:高速運算放大器 Quad Low-Power Current Feedback RoHS:否 制造商:Texas Instruments 通道數(shù)量:1 電壓增益 dB:116 dB 輸入補償電壓: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 安裝風格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
發(fā)布緊急采購，3分鐘左右您將得到回復。