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參數(shù)資料
| 型號： | OPA655 |
| 元件分類： | 運動控制電子 |
| 英文描述： | Wideband, Unity Gain Stable, FET-Input OPERATIONAL AMPLIFIER |
| 中文描述： | 寬帶，單位增益穩(wěn)定，F(xiàn)ET輸入運算放大器 |
| 文件頁數(shù)： | 11/14頁 |
| 文件大?。?/td> | 222K |
| 代理商： | OPA655 |
11
OPA655
differential gain of 1.5V/V (3.5dB) to the matched load as
shown in Figure 10. The C
T
tuning capacitor is used to
match the high frequency gains for the two signal paths to
improve the high frequency CMRR. Using this adjustment,
a CMRR > 40dB through 100MHz was achieved.
HIGH SPEED INSTRUMENTATION
DIFFERENTIAL AMPLIFIER
Very high speed differential amplifiers can be implemented
using the OPA655. The very low input bias currents allow
relatively high resistor values to be used in a standard single
op amp differential configuration. Alternatively, a very high
input impedance differential amplifier can be implemented
using a three op amp instrumentation amplifier topology as
shown in Figure 9.
FIGURE 8. Maximally Flat Bandwidth.
FIGURE 9. High Input Impedance, Broadband INA.
50
Load
50
OPA651
V
–
V
+
R
G
100
R
F
100
300
300
R
F
100
OPA655
OPA655
300
C
T
1.5 to 6pF
300
In this example, the OPA655’s provide a differential gain of:
and a common mode gain of 1 to the input of the OPA651
differential stage. The OPA651, a gain of 2 stable, broad-
band voltage feedback op amp, rejects the common mode
signal and provides a differential gain of 1/2 the matched
50
load. This circuit delivers a 136MHz bandwidth at a
1
+
2R
F
R
G
=
3
FIGURE 10. Measured Frequency Response for INA.
DIFFERENTIAL INPUT
3.5dB
2.5
1.5
.5
1M
10M
100M
1G
136MHz
OPTIMIZING PERFORMANCE
DC ACCURACY
The OPA655 is laser trimmed for low input offset voltage,
limiting the need for external trim circuits. In most cases, the
low bias current of the FET input will not contribute signifi-
cantly to the output DC error. For example, at minimum gain
(G = +1) and maximum temperature (85
°
C), the error
contribution due to the inverting input bias current would
only exceed the input offset voltage for feedback resistors >
(1mV/3.2nA) = 312k
. Only for relatively high source and/
or feedback resistor values will the input bias current con-
tribute significantly to the output DC error. Similarly, since
the two input bias currents are very low, but not tightly
matched, input bias current cancellation through source
impedance matching is not recommended.
Changes in the power supply voltages contribute to shifts
in the input offset voltage. This can be calculated using
the PSR specifications. For example, a 0.5V change in
the negative power supply will show up typically as a
0.5V 10
(–65/20)
= 0.28mV change in the input offset voltage.
Negative common mode voltage inputs can cause an in-
crease in the input bias currents as shown in the Typical
Performance Curves. This can have an effect on DC accu-
racy when the source and/or feedback resistors are large and
the common mode input voltage approaches the negative
limit of –2.5V. Positive input biases are therefore preferred
for diode transimpedance applications requiring a bias volt-
age on the non-inverting op amp input.
BANDWIDTH vs R
F
–
10
30
10
0.3
1
Transimpedance Gain, R
F
(k
)
100
1000
C
D
= 10pF
C
D
=50pF
C
D
= 20pF
C
D
= 100pF
C
D
= 200pF
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PDF描述 |
|---|---|
| OPA655P | Wideband, Unity Gain Stable, FET-Input OPERATIONAL AMPLIFIER |
| OPA655U | Wideband, Unity Gain Stable, FET-Input OPERATIONAL AMPLIFIER |
| OPA671AP | Wide Bandwidth, Fast Settling Difet OPERATIONAL AMPLIFIER |
| OPA671 | Wide Bandwidth, Fast Settling Difet OPERATIONAL AMPLIFIER |
| OPA683ID | OP-AMP|SINGLE|BIPOLAR|SOP|8PIN|PLASTIC |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| OPA655P | 制造商:BB 制造商全稱:BB 功能描述:Wideband, Unity Gain Stable, FET-Input OPERATIONAL AMPLIFIER |
| OPA655P | 制造商:Texas Instruments 功能描述:OP AMP WIDEBAND FET IP DIP8 655 |
| OPA655U | 功能描述:IC OPAMP VFB 240MHZ SGL WB 8SOIC RoHS:否 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 產(chǎn)品變化通告:Discontinuation 18/May/2012 標準包裝:2,000 系列:- 放大器類型:通用 電路數(shù):4 輸出類型:滿擺幅 轉(zhuǎn)換速率:0.42 V/µs 增益帶寬積:1.5MHz -3db帶寬:- 電流 - 輸入偏壓:15nA 電壓 - 輸入偏移:1000µV 電流 - 電源:116µA 電流 - 輸出 / 通道:100mA 電壓 - 電源，單路/雙路(±):1.8 V ~ 5 V，±0.9 V ~ 2.5 V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:14-TSSOP（0.173"，4.40mm 寬） 供應(yīng)商設(shè)備封裝:14-TSSOP 包裝:帶卷 (TR) 產(chǎn)品目錄頁面:851 (CN2011-ZH PDF) 其它名稱:296-20930-2 |
| OPA656 | 制造商:BB 制造商全稱:BB 功能描述:Precision, High-Speed Transimpedance Amplifier |
| OPA656-DIE | 制造商:TI 制造商全稱:Texas Instruments 功能描述:WIDEBAND, UNITY-GAIN STABLE, FET-INPUT OPERATIONAL AMPLIFIER |
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