- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄383693 > OPA623 Wide Bandwidth, Current-Feedback OPERATIONAL AMPLIFIER PDF資料下載
參數(shù)資料
| 型號： | OPA623 |
| 英文描述： | Wide Bandwidth, Current-Feedback OPERATIONAL AMPLIFIER |
| 中文描述： | 寬帶，電流反饋運算放大器 |
| 文件頁數(shù)： | 10/15頁 |
| 文件大小： | 254K |
| 代理商： | OPA623 |
10
OPA623
FIGURE 3. Non-Inverting Current-Feedback Op Amp Configuration.
B
1
–V
CC
V
IN
+V
CC
R
IN
+In
–In
R
1
R
2
Out
V
OUT
7
3
4
2
6
lines or loads. The buffer output is not current-limited or
protected.
As can be seen in Figure 3, the feedback in the form of a
current is applied through R
2
to the low-impedance inverting
input, and the size of R
2
||
R
1
determines the open-loop gain
of the op amp.
The hybrid model shown in Figure 4 describes the AC
behavior of a wide-band current-feedback op amp that is not
internally compensated. The open-loop frequency response,
which is illustrated in Figure 5 for various R
2
values, is
determined by two time constants. The elements R and C
between the current source output and the output buffer form
the dominant open-loop pole T
C
. The signal delay time T
D
modelled in the output buffer combines several small phase-
shifting time constants and delay times. They are distributed
throughout the amplifiers and are also present in the feed-
back loop. As shown in Figure 5, increasing R
2
|| R
1
leads to
a decreasing open-loop gain. The ratio of the two time
constants T
C
and T
D
also determines the product G
OL
G
CL
for optimal closed-loop frequency response:
FIGURE 4. Hybrid Model OPA623.
–1
R
2
R
1
g
m
+In
3
2
6
R
T
C
T
Out
T
D
–In
provides a nearly constant closed-loop bandwidth, as shown
in Figure 6 for various gains with an optimal flat frequency
response. This behavior stands in contrast to op amps that
are internally compensated for stable unity-gain operation,
where the bandwidth is inversely proportional to the closed-
loop gain, sharply limiting the bandwidth and slew rate at
high output levels and gains.
In general, lower feedback resistors produce wider band-
width, more frequency response peaking, and more pulse
response overshooting. Higher feedback resistors results in
an overdamped response with little or no peaking and
overshooting.
Component pin and layout capacitances together with trace
and wire board inductances from a resonant IC circuit can
lead to oscillations of several hundreds of MHz. This very
high frequency oscillation leads to an excessive increase in
supply current which can destroy the device.
A resistor (100
to 250
) in series and close to the high-
impedance, non-inverting input damps the LC circuit and
generates a safe operation.
THERMAL CONSIDERATIONS
The OPA623 does not require a heat sink for operation in
most environments. The use of a heat sink, however, will
The two time constants T
C
and T
D
, however, are fixed by the
op amp design. But varying R
2
|| R
1
externally in the
feedback loop allows for variation of the open-loop gain
G
OL
versus the closed-loop gain G
CL
. This keeps the product
G
OL
* G
CL
constant, which is the theoretical condition for
optimally flat frequency response.
This variation may be beneficial when driving high capaci-
tive loads. Setting the open-loop gain externally also allows
the circuit to be optimized to a wide range of capacitive
loads, as shown in Figure 7 for a closed-loop gain of
+2V/V and a capacitive load of up to 47pF.
It should be noted here that higher open-loop gain (resulting
from lower feedback resistors) also yields lower distortion.
With external control of the open-loop characteristics of the
op amp, dynamic behavior can be tailored to individual
application requirements, and the open-loop gain selection
T
C
2T
D
+
G
OL
= G
CL
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| OPA623AP | Wide Bandwidth, Current-Feedback OPERATIONAL AMPLIFIER |
| OPA623AU | Wide Bandwidth, Current-Feedback OPERATIONAL AMPLIFIER |
| OPA628AU | Low Distortion Wideband OPERATIONAL AMPLIFIER |
| OPA628 | Low Distortion Wideband OPERATIONAL AMPLIFIER |
| OPA654 | Wide Bandwidth, High Output Current Difet OPERATIONAL AMPLIFIER |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| OPA623 WAF | 制造商:Texas Instruments 功能描述: |
| OPA623AP | 制造商:BB 制造商全稱:BB 功能描述:Wide Bandwidth, Current-Feedback OPERATIONAL AMPLIFIER |
| OPA623AU | 制造商:BB 制造商全稱:BB 功能描述:Wide Bandwidth, Current-Feedback OPERATIONAL AMPLIFIER |
| OPA6250 | 制造商:TI 制造商全稱:Texas Instruments 功能描述:Wideband, Unity-Gain Stable, FET-Input OPERATIONAL AMPLIFIER |
| OPA625IDBVT | 功能描述:General Purpose Amplifier 1 Circuit Rail-to-Rail SOT-23-6 制造商:texas instruments 系列:- 包裝:剪切帶（CT） 零件狀態(tài):有效 放大器類型:通用 電路數(shù):1 輸出類型:滿擺幅 壓擺率:115 V/μs 增益帶寬積:120MHz -3db 帶寬:- 電流 - 輸入偏置:2μA 電壓 - 輸入失調(diào):100μV 電流 - 電源:2mA 電流 - 輸出/通道:150mA 電壓 - 電源，單/雙（±）:2.7 V ~ 5.5 V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-6 供應(yīng)商器件封裝:SOT-23-6 標準包裝:1 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。