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參數(shù)資料
| 型號： | OP285ES |
| 英文描述： | Voltage-Feedback Operational Amplifier |
| 中文描述： | 電壓反饋運算放大器 |
| 文件頁數(shù)： | 9/16頁 |
| 文件大小： | 248K |
| 代理商： | OP285ES |
REV. A
OP285
–9–
+15V
2
3
8
1
4
V
IN
V
OUT
–
15V
10pF
+
+
0.1 F
4.99k
2k
0.1 F
10 F
2.49k
4.99k
+
–
OP285
1/2
Figure 9. Unity-Gain Inverter
In inverting and noninverting applications, the feedback resis-
tance forms a pole with the source resistance and capacitance
(R
S
and C
S
) and the OP285’s input capacitance (C
IN
), as
shown in Figure 10. With R
S
and R
F
in the kilohm range, this
pole can create excess phase shift and even oscillation. A small
capacitor, C
FB
, in parallel with R
FB
eliminates this problem. By
setting R
S
(C
S
+ C
IN
) = R
FB
C
FB
, the effect of the feedback pole
is completely removed.
C
FB
R
FB
C
IN
V
OUT
R
S
C
S
Figure 10. Compensating the Feedback Pole
High-Speed, Low-Noise Differential Line Driver
The circuit of Figure 11 is a unique line driver widely used in
industrial applications. With
±
18 V supplies, the line driver can
deliver a differential signal of 30 V p-p into a 2.5 k
load. The
high slew rate and wide bandwidth of the OP285 combine to
yield a full power bandwidth of 130 kHz while the low noise
front end produces a referred-to-input noise voltage spectral
density of 10 nV/
√
Hz. The design is a transformerless, balanced
transmission system where output common-mode rejection of
noise is of paramount importance. Like the transformer-based
design, either output can be shorted to ground for unbalanced
line driver applications without changing the circuit gain of 1.
Other circuit gains can be set according to the equation in the
diagram. This allows the design to be easily set to noninverting,
inverting, or differential operation.
2
3
A2
1
3
2
A1
5
6
7
A3
V
IN
V
O1
V
O2
V
O2
–
V
O1
= V
IN
R2
2k
A1 = 1/2OP285
A2, A3 = 1/2 OP285
GAIN = SET R2, R4, R5 = R1 AND R, R7, R8 = R2
1
R1
2k
R3
2k
R9
50
R11
1k
P1
10k
R12
1k
R4
2k
R5
2k
R6
2k
R10
50
R8
2k
R7
2k
Figure 11. High-Speed, Low-Noise Differential Line Driver
Low Phase Error Amplifier
The simple amplifier configuration of Figure 12 uses the OP285
and resistors to reduce phase error substantially over a wide
frequency range when compared to conventional amplifier designs.
This technique relies on the matched frequency characteristics
of the two amplifiers in the OP285. Each amplifier in the circuit
has the same feedback network which produces a circuit gain of
10. Since the two amplifiers are set to the same gain and are
matched due to the monolithic construction of the OP285, they
will exhibit identical frequency response. Recall from feedback
theory that a pole of a feedback network becomes a zero in the
loop gain response. By using this technique, the dominant pole
of the amplifier in the feedback loop compensates for the domi-
nant pole of the main amplifier,
1
2
3
A1
7
A2
5
6
R1
549
R2
4.99k
R3
499
V
IN
V
OUT
R5
549
R4
4.99
A1, A2 = 1/2 OP285
Figure 12. Cancellation of A2’s Dominant Pole by A1
相關PDF資料 |
PDF描述 |
|---|---|
| OP285FP | Voltage-Feedback Operational Amplifier |
| OP285FS | Voltage-Feedback Operational Amplifier |
| OP285GS | Dual 9 MHz Precision Operational Amplifier |
| OP285GSR | Dual 9 MHz Precision Operational Amplifier |
| OP285 | Dual 9 MHz Precision Operational Amplifier |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| OP285FP | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Voltage-Feedback Operational Amplifier |
| OP285FS | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Voltage-Feedback Operational Amplifier |
| OP285G | 制造商:Analog Devices 功能描述: |
| OP-285GBC | 制造商:AD 制造商全稱:Analog Devices 功能描述:DUAL, 9MHz PRECISION OPERATIONAL AMPLIFIER |
| OP285GP | 制造商:Analog Devices 功能描述:IC OP AMP DUAL 9MHZ DIP8 285 |
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