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參數(shù)資料
| 型號： | OPA3681U |
| 英文描述： | Triple Wideband, Current-Feedback OPERATIONAL AMPLIFIER With Disable |
| 中文描述： | 三寬帶，電流反饋運算放大器，禁用 |
| 文件頁數(shù)： | 15/21頁 |
| 文件大?。?/td> | 234K |
| 代理商： | OPA3681U |
15
OPA3681
OPERATING SUGGESTIONS
SETTING RESISTOR VALUES TO
OPTIMIZE BANDWIDTH
A current-feedback op amp like the OPA3681 can hold an
almost constant bandwidth over signal gain settings with the
proper adjustment of the external resistor values. This is shown
in the Typical Performance Curves; the small signal bandwidth
decreases only slightly with increasing gain. These curves also
show that the feedback resistor has been changed for each gain
setting. The resistor “values” on the inverting side of the circuit
for a current feedback op amp can be treated as frequency
response compensation elements while their “ratios” set the
signal gain. Figure 9 shows the small-signal frequency response
analysis circuit for the OPA3681.
The key elements of this current-feedback op amp model are:
α
→
Buffer gain from the non-inverting input to the inverting input
R
I
→
Buffer output impedance
i
ERR
→
Feedback error current signal
Z(s)
→
Frequency dependent open loop transimpedance gain from i
ERR
to V
O
The buffer gain is typically very close to 1.00 and is
normally neglected from signal gain considerations. It will,
however, set the CMRR for a single op amp differential
amplifier configuration. For a buffer gain
α
< 1.0, the
CMRR = –20
log (1–
α
) dB.
R
I
, the buffer output impedance, is a critical portion of the
bandwidth control equation. The OPA3681 is typically 42
.
1/3
OPA3681
10
20
499
499
G = +2
1/3
OPA3681
10
20
140
422
G = +4
1/3
OPA3681
10
20
35.7
249
G = +8
74HC238
50
50
Load
–5V
+5V
Power Supply
De-Coupling Not Shown
V
IN
+5V
D
1
D
2
Y
0
Y
1
Y
2
50
FIGURE 9. Current Feedback Transfer Function Analysis
Circuit.
FIGURE 8. Wideband Programmable Gain.
R
F
V
O
R
G
R
I
Z
(S)
i
ERR
i
ERR
α
V
I
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PDF描述 |
|---|---|
| OPA3682 | Triple, Wideband, Fixed Gain BUFFER AMPLIFIER With Disable |
| OPA3682E | Triple, Wideband, Fixed Gain BUFFER AMPLIFIER With Disable |
| OPA3682U | Triple, Wideband, Fixed Gain BUFFER AMPLIFIER With Disable |
| OPA404KU | 256K, 32K X 8, 2.5V HI-SPEED SER EE, -40C to +85C, 8-PDIP, TUBE |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| OPA3681U/2K5 | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| OPA3682 | 制造商:BB 制造商全稱:BB 功能描述:Triple, Wideband, Fixed Gain BUFFER AMPLIFIER With Disable |
| OPA3682E | 制造商:BB 制造商全稱:BB 功能描述:Triple, Wideband, Fixed Gain BUFFER AMPLIFIER With Disable |
| OPA3682E/250 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog Buffer/Voltage Follower |
| OPA3682E/2K5 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog Buffer/Voltage Follower |
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