參數(shù)資料
型號: OPA682N
英文描述: Wideband, Fixed Gain BUFFER AMPLIFIER With Disable
中文描述: 寬帶,固定增益緩沖放大器具有禁用
文件頁數(shù): 13/20頁
文件大?。?/td> 213K
代理商: OPA682N
13
OPA682
APPLICATIONS INFORMATION
WIDEBAND BUFFER OPERATION
The OPA682 gives the exceptional AC performance of a
wideband current feedback op amp with a highly linear, high
power output stage. It features internal R
F
and R
G
resistors
which make it easy to select a gain of +2, +1 or –1 without
any external resistors. Requiring only 6mA quiescent cur-
rent, the OPA682 will swing to within 1V of either supply
rail and deliver in excess of 135mA guaranteed at room
temperature. This low output headroom requirement, along
with supply voltage independent biasing, gives remarkable
single (+5V) supply operation. The OPA682 will deliver
greater than 200MHz bandwidth driving a 2Vp-p output into
100
on a single +5V supply. Previous boosted output stage
amplifiers have typically suffered from very poor crossover
distortion as the output current goes through zero. The
OPA682 achieves a comparable power gain with much
better linearity. The primary advantage of a current feedback
op amp over a voltage feedback op amp is that AC perfor-
mance (bandwidth and distortion) is relatively independent
of signal gain.
Figure 1 shows the DC coupled, gain of +2, dual power
supply circuit configuration used as the basis of the
±
5V
Specifications and Typical Performance Curves. For test
purposes, the input impedance is set to 50
with a resistor
to ground and the output impedance is set to 50
with a
series output resistor. Voltage swings reported in the speci-
fications are taken directly at the input and output pins while
load powers (dBm) are defined at a matched 50
load. For
the circuit of Figure 1, the total effective load will be 100
|| 800
= 89
. The disable control line (DIS) is typically left
open to guarantee normal amplifier operation. In addition to
the usual power supply decoupling capacitors to ground, a
0.1
μ
F capacitor can be included between the two power
supply pins. This optional added capacitor will typically
improve the 2nd harmonic distortion performance by 3dB to
6dB.
FIGURE 1. DC-Coupled, G = +2, Bipolar Supply, Specifi-
cation and Test Circuit.
FIGURE 2. AC-Coupled, G = +2, Single Supply Specifica-
tion and Test Circuit.
Figure 2 shows the AC coupled, gain of +2, single-supply
circuit configuration used as the basis of the +5V Specifica-
tions and Typical Performance Curves. Though not a “rail-
to-rail” design, the OPA682 requires minimal input and
output voltage headroom compared to other very wideband
current feedback op amps. It will deliver a 3Vp-p output
swing on a single +5V supply with greater than 150MHz
bandwidth. The key requirement of broadband single-supply
operation is to maintain input and output signal swings
within the usable voltage ranges at both the input and the
output. The circuit of Figure 2 establishes an input midpoint
bias using a simple resistive divider from the +5V supply
(two 806
resistors). The input signal is then AC-coupled
into this midpoint voltage bias. The input voltage can swing
to within 1.5V of either supply pin, giving a 2Vp-p input
signal range centered between the supply pins. The input
impedance matching resistor (57.6
) used for testing is
adjusted to give a 50
input match when the parallel
combination of the biasing divider network is included. The
gain resistor (R
G
) is AC-coupled, giving the circuit a DC
gain of +1—which puts the input DC bias voltage (2.5V) on
the output as well. Again, on a single +5V supply, the output
voltage can swing to within 1V of either supply pin while
delivering more than 80mA output current. A demanding
100
load to a midpoint bias is used in this characterization
circuit. The new output stage used in the OPA682 can
deliver large bipolar output currents into this midpoint load
with minimal crossover distortion, as shown by the +5V
supply, 3rd harmonic distortion plots.
SINGLE-SUPPLY A/D CONVERTER INTERFACE
Most modern, high performance A/D converters (such as the
Burr-Brown ADS8xx and ADS9xx series) operate on a
single +5V (or lower) power supply. It has been a consider-
able challenge for single-supply op amps to deliver a low
distortion input signal at the ADC input for signal frequen-
OPA682
+5V
–5V
50
Load
50
50
50
Source
R
G
400
R
F
400
+
6.8
μ
F
0.1
μ
F
+
6.8
μ
F
0.1
μ
F
DIS
V
IN
OPA682
+5V
+V
S
DIS
V
S
/2
806
100
V
O
V
IN
806
R
G
400
R
F
400
0.1
μ
F
0.1
μ
F
+
6.8
μ
F
0.1
μ
F
50
Source
57.6
相關(guān)PDF資料
PDF描述
OPA682P Wideband, Fixed Gain BUFFER AMPLIFIER With Disable
OPA686U Wideband, Low Noise, Voltage Feedback OPERATIONAL AMPLIFIER
OPA686N Wideband, Low Noise, Voltage Feedback OPERATIONAL AMPLIFIER
OPA686 Wideband, Low Noise, Voltage Feedback OPERATIONAL AMPLIFIER
OPA687N Wideband, Ultra-Low Noise, Voltage Feedback OPERATIONAL AMPLIFIER With Power Down
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
OPA682N/250 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Texas Instruments 功能描述:
OPA682N/3K 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog Buffer/Voltage Follower
OPA682P 功能描述:高速運算放大器 DIP-8 WB Fixed Gain RoHS:否 制造商:Texas Instruments 通道數(shù)量:1 電壓增益 dB:116 dB 輸入補償電壓: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
OPA682U 功能描述:高速運算放大器 Wb Fixed Gain RoHS:否 制造商:Texas Instruments 通道數(shù)量:1 電壓增益 dB:116 dB 輸入補償電壓: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
OPA682U/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