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參數(shù)資料
| 型號(hào)： | OPA689P |
| 元件分類： | 運(yùn)動(dòng)控制電子 |
| 英文描述： | Wideband, High Gain VOLTAGE LIMITING AMPLIFIER |
| 中文描述： | 寬帶，高增益電壓限幅放大器 |
| 文件頁數(shù)： | 15/16頁 |
| 文件大?。?/td> | 175K |
| 代理商： | OPA689P |
15
OPA689
OPA689
C
L
R
L
R
ISO
R
L
is optional
V
O
OFFSET VOLTAGE ADJUSTMENT
The circuit in Figure 9 allows offset adjustment without
degrading offset drift with temperature. Use this circuit with
caution since power supply noise can inadvertently couple
into the op amp.
Remember that additional offset errors can be created by the
amplifier’s input bias currents. Whenever possible, match
the resistance seen by both DC Input Bias Currents by using
R
3
. This minimizes the output offset voltage caused by the
Input Bias Currents.
FIGURE 9. Offset Voltage Trim.
OUTPUT DRIVE
The OPA689 has been optimized to drive 500
loads, such
as A/D converters. It still performs very well driving 100
loads. This makes the OPA689 an ideal choice for a wide
range of high frequency applications.
Many high speed applications, such as driving A/D convert-
ers, require op amps with low output impedance. As shown
in the
Output Impedance vs Frequency
performance curve,
the OPA689 maintains very low closed-loop output imped-
ance over frequency. Closed-loop output impedance in-
creases with frequency since loop gain decreases with fre-
quency.
THERMAL CONSIDERATIONS
The OPA689 will not require heat-sinking under most oper-
ating conditions. Maximum desired junction temperature
will set a maximum allowed internal power dissipation as
described below. In no case should the maximum junction
temperature be allowed to exceed 175
°
C.
The total internal power dissipation (P
D
) is the sum of
quiescent power (P
DQ
) and the additional power dissipated
in the output stage (P
DL
) while delivering load power. P
DQ
is simply the specified no-load supply current times the total
supply voltage across the part. P
DL
depends on the required
output signals and loads. For a grounded resistive load,
and equal bipolar supplies, it is at a maximum when the
output is at 1/2 either supply voltage. In this condition,
P
DL
= V
S2
/(4R
L
) where R
L
includes the feedback network
loading. Note that it is the power in the output stage, and not
in the load, that determines internal power dissipation.
The operating junction temperature is: T
J
= T
A
+ P
D
θ
JA
,
where T
A
is the ambient temperature.
For example, the maximum T
J
for a OPA689U with G = +6,
R
FB
= 750
, R
L
= 100
, and
±
V
S
=
±
5V at the maximum
T
A
= +85
°
C is calculated this way:
(
)
2
4
100
||
850
(
P
D
= 200
mW
+ 70
mW
= 270
mW
T
J
= 85°
C
+ 270
mW
125°
C/W
=119°
C
P
DQ
= 10
V
20
mA
)
= 200
mW
P
DL
=
5
V
)
CAPACITIVE LOADS
Capacitive loads, such as flash A/D converters, will decrease
the amplifier’s phase margin, which may cause peaking or
oscillations. Capacitive loads
≥
1pF should be isolated by
connecting a small resistor in series with the output as shown
in Figure 10. Increasing the gain from +6 will improve the
capacitive drive capabilities due to increased phase margin.
FIGURE 10. Driving Capacitive Loads.
In general, capacitive loads should be minimized for opti-
mum high frequency performance. The capacitance of coax
cable (29pF/foot for RG-58) will not load the amplifier
when the coaxial cable, or transmission line, is terminated in
its characteristic impedance.
R2
OPA689
R3 = R
1
|| R
2
R1
R
TRIM
47k
+V
S
V
O
–V
S
V
IN
or Ground
0.1μF
NOTES: (1) R
is optional and minimizes
output offset due to input bias currents. (2) Set
R
1
<< R
TRIM
.
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PDF描述 |
|---|---|
| OPA689 | Wideband, High Gain VOLTAGE LIMITING AMPLIFIER |
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| OPA693IDR | Ultra-Wideband, Fixed Gain Video BUFFER AMPLIFIER with Disable |
| OPA693 | Ultra-Wideband, Fixed Gain Video BUFFER AMPLIFIER with Disable |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| OPA689U | 制造商:BB 制造商全稱:BB 功能描述:EVALUATION FIXTURE |
| OPA689U/2K5 | 制造商:Rochester Electronics LLC 功能描述:OP AMP WIDEBAND VOLT LIMITING - Bulk 制造商:Texas Instruments 功能描述: |
| OPA690 | 制造商:BB 制造商全稱:BB 功能描述:Low-Power, Single-Supply, Wideband Operational Amplifier |
| OPA690ID | 功能描述:高速運(yùn)算放大器 Wideband Voltage Feeback RoHS:否 制造商:Texas Instruments 通道數(shù)量:1 電壓增益 dB:116 dB 輸入補(bǔ)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(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
| OPA690ID | 制造商:Texas Instruments 功能描述:IC SM OP-AMP WIDEBAND VFB |
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