參數(shù)資料
型號: OPA341
英文描述: SINGLE-SUPPLY, RAIL-TO-RAIL OPERATIONAL AMPLIFIER WITH SHUTDOWN
中文描述: 單電源,軌至軌運(yùn)算放大器具有關(guān)斷
文件頁數(shù): 10/13頁
文件大?。?/td> 236K
代理商: OPA341
OPA341, 2341
SBOS202A
10
FIGURE 3. Input Current Protection for Voltages Exceeding
the Supply Voltage.
FIGURE 4. Series Resistor in Unity-Gain Configuration Improves Capacitive Load Drive.
A double-folded cascode adds the signal from the two input
pairs and presents a differential signal to the class AB output
stage. Normally, input bias current is approximately 600fA,
however, input voltages exceeding the power supplies by
more than 300mV can cause excessive current to flow in or
out of the input pins. Momentary voltages greater than
300mV beyond the power supply can be tolerated if the
current on the input pins is limited to 10mA. This is easily
accomplished with an input resistor, as shown in Figure 3.
Many input signals are inherently current-limited to less
than 10mA, therefore, a limiting resistor is not required.
RAIL-TO-RAIL OUTPUT
A class AB output stage with common-source transistors is
used to achieve rail-to-rail output. For light resistive loads
(> 50k
), the output voltage is typically a few millivolts
from the supply rails. With moderate resistive loads (2k
to
50k
), the output can swing to within a few tens of milli-
volts from the supply rails and maintain high open-loop
gain. See the typical characteristic “Output Voltage Swing
vs Output Current.”
CAPACITIVE LOAD AND STABILITY
OPA341 series op amps can drive a wide range of capacitive
loads. However, all op amps under certain conditions may
become unstable. Op amp configurations, gain, and load
value are just a few of the factors to consider when determin-
ing stability. An op amp in unity-gain configuration is the
most susceptible to the effects of capacitive load. The
capacitive load reacts with the op amp’s output resistance,
along with any additional load resistance, to create a pole in
the small-signal response which degrades the phase margin.
In unity gain, OPA341 series op amps perform well, with a
pure capacitive load up to approximately 1000pF. Increasing
gain enhances the amplifier’s ability to drive more capaci-
tance. See the typical characteristic “Small-Signal Over-
shoot vs Capacitive Load.”
One method of improving capacitive load drive in the unity-
gain configuration is to insert a 10
to 20
resistor in series
with the output, as shown in Figure 4. This significantly
reduces ringing with large capacitive loads. However, if there
is a resistive load in parallel with the capacitive load, R
S
creates a voltage divider. This introduces a DC error at the
output and slightly reduces output swing. This error may be
insignificant. For instance, with R
L
= 10k
and R
S
= 20
,
there is only about a 0.2% error at the output.
DRIVING A/D CONVERTERS
OPA341 series op amps are optimized for driving medium
speed (up to 100kHz) sampling A/D converters. However,
they also offer excellent performance for higher-speed con-
verters. The OPA341 series provides an effective means of
buffering the A/D converter’s input capacitance and result-
ing charge injection while providing signal gain. For appli-
cations requiring high accuracy, the OPA340 series is rec-
ommended.
The OPA341 implements a power-saving shutdown feature
particularly useful for low-power sampling applications. Figure 5
shows the OPA341 driving the ADS7816, a 12-bit micro-power
sampling converter available in the tiny MSOP-8 package. With
the OPA341 in non-inverting configuration, an RC network at the
amplifier’s output is used as an anti-aliasing filter. By tying the
enable of the OPA341 to the shutdown of the ADS7816, addi-
tional power-savings can be used for sampling applications. To
effectively drive the ADS7816, timing delay was introduced
between the two devices, see Figure 5. Alternative applications
may need additional timing adjustments.
Figure 6 shows the OPA341 configured as a speech band-
pass filter. Figure 7 shows the OPA341 configured as a
transimpedance amplifier.
OPAx341
10mA max
V+
V
IN
V
OUT
I
OVERLOAD
10
to
20
OPAx341
V+
V
ENABLE
V
IN
V
OUT
R
S
R
L
C
L
相關(guān)PDF資料
PDF描述
OPA2341 SINGLE-SUPPLY, RAIL-TO-RAIL OPERATIONAL AMPLIFIER WITH SHUTDOWN
OPA345NA LOW POWER, SINGLE-SUPPLY, RAIL-TO-RAIL OPERATIONAL AMPLIFIERS MicroAmplifier ⑩ Series
OPA345UA LOW POWER, SINGLE-SUPPLY, RAIL-TO-RAIL OPERATIONAL AMPLIFIERS MicroAmplifier ⑩ Series
OPA4344 LOW POWER, SINGLE-SUPPLY, RAIL-TO-RAIL OPERATIONAL AMPLIFIERS MicroAmplifier ⑩ Series
OPA2345EA LOW POWER, SINGLE-SUPPLY, RAIL-TO-RAIL OPERATIONAL AMPLIFIERS MicroAmplifier ⑩ Series
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
OPA341_08 制造商:BB 制造商全稱:BB 功能描述:SINGLE-SUPPLY, RAIL-TO-RAIL OPERATIONAL AMPLIFIER WITH SHUTDOWN microAmplifier ? Series
OPA341NA/250 功能描述:運(yùn)算放大器 - 運(yùn)放 Single 5.5MHz RRIO Low Power RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比(最小值):63 dB 輸入補(bǔ)償電壓:1 mV 輸入偏流(最大值):10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-16 轉(zhuǎn)換速度:0.89 V/us 關(guān)閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel
OPA341NA/250G4 功能描述:運(yùn)算放大器 - 運(yùn)放 Single 5.5MHz RRIO Low Power RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比(最小值):63 dB 輸入補(bǔ)償電壓:1 mV 輸入偏流(最大值):10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-16 轉(zhuǎn)換速度:0.89 V/us 關(guān)閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel
OPA341NA/3K 功能描述:運(yùn)算放大器 - 運(yùn)放 Single 5.5MHz RRIO Low Power RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比(最小值):63 dB 輸入補(bǔ)償電壓:1 mV 輸入偏流(最大值):10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-16 轉(zhuǎn)換速度:0.89 V/us 關(guān)閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel
OPA341NA/3KG4 功能描述:運(yùn)算放大器 - 運(yùn)放 Single 5.5MHz RRIO Low Power RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比(最小值):63 dB 輸入補(bǔ)償電壓:1 mV 輸入偏流(最大值):10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-16 轉(zhuǎn)換速度:0.89 V/us 關(guān)閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel