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参数资料
| 型号： | AD823AR |
| 厂商： | ANALOG DEVICES INC |
| 元件分类： | 运动控制电子 |
| 英文描述： | Dual, 16 MHz, Rail-to-Rail FET Input Amplifier |
| 中文描述： | DUAL OP-AMP, 3500 uV OFFSET-MAX, PDSO8 |
| 封装： | PLASTIC, MS-012AA, SOIC-8 |
| 文件页数： | 12/16页 |
| 文件大小： | 439K |
| 代理商： | AD823AR |
REV. 0
–12–
AD823
The first pole in the denominator is the dominant pole of the
amplifier, and occurs at about 18 Hz. This equals the input
stage output impedance R1 multiplied by the Miller-multiplied
value of C1. The second pole occurs at the unity-gain band-
width of the output stage, which is 23 MHz. This type of archi-
tecture allows more open loop gain and output drive to be
obtained than a standard two-stage architecture would allow.
OUTPUT IMPEDANCE
The low frequency open loop output impedance of the
common-emitter output stage used in this design is approxi-
mately 30 k
. While this is significantly higher than a typical
emitter follower output stage, when connected with feedback
the output impedance is reduced by the open loop gain of the
op amp. With 109 dB of open loop gain the output impedance
is reduced to less than 0.2
. At higher frequencies the output
impedance will rise as the open loop gain of the op amp drops;
however, the output also becomes capacitive due to the integra-
tor capacitors C1 and C2. This prevents the output impedance
from ever becoming excessively high (see Figure 17), which can
cause stability problems when driving capacitive loads. In fact,
the AD823 has excellent cap-load drive capability for a high fre-
quency op amp. Figure 33 shows the AD823 connected as a fol-
lower while driving 470 pF direct capacitive load. Under these
conditions the phase margin is approximately 20
°
. If greater
phase margin is desired a small resistor can be used in series
with the output to decouple the effect of the load capacitance
from the op amp (see Figure 25). In addition, running the part
at higher gains will also improve the capacitive load drive capa-
bility of the op amp.
V
OUT
S1N
C1
S1P
C5
R1
R1
g
m
VI
g
m
VI
g
m2
C2
R2
Figure 36. Small Signal Schematic
APPLICATION NOTES
INPUT CHARACTERISTICS
In the AD823, n-channel JFETs are used to provide a low
offset, low noise, high impedance input stage. Minimum input
common-mode voltage extends from 0.2 V below –V
S
to 1 V
less than +V
S
. Driving the input voltage closer to the positive
rail will cause a loss of amplifier bandwidth and increased
common-mode voltage error.
The AD823 does not exhibit phase reversal for input voltages
up to and including +V
S
. Figure 37a shows the response of an
AD823 voltage follower to a 0 V to +5 V (+V
S
) square wave
input. The input and output are superimposed. The output
polarity tracks the input polarity up to +V
S
—no phase reversal.
The reduced bandwidth above a 4 V input causes the rounding
of the output wave form. For input voltages greater than +V
S
, a
resistor in series with the AD823’s plus input will prevent phase
reversal, at the expense of greater input voltage noise. This is il-
lustrated in Figure 37b.
GND
10
90
100
0%
1V
2
μ
s
1V
a. Response with R
P
= 0; V
IN
from 0 to V
S
+V
S
GND
10
0%
90
100
1V
1V
10μs
1V
+5V
V
IN
R
P
V
OUT
AD823
b. V
IN
= 0 to +V
S
+ 200 mV; V
OUT
= 0 to +V
S
; R
P
= 49.9 k
Figure 37. AD823 Input Response
相关PDF资料 |
PDF描述 |
|---|---|
| AD823AR-REEL | RECTIFIER SCHOTTKY SINGLE 8A 30V 200A-ifsm 0.55V-vf 0.5mA-ir TO220AC 50/TUBE |
| AD824AN-3V | VARISTOR 30VRMS 1206 SMD |
| AD824 | Single Supply, Rail-to-Rail Low Power, FET-Input Op Amp |
| AD824AN | Single Supply, Rail-to-Rail Low Power, FET-Input Op Amp |
| AD824AR | Single Supply, Rail-to-Rail Low Power, FET-Input Op Amp |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AD823AR | 制造商:Analog Devices 功能描述:SEMICONDUCTORS LINEAR |
| AD823AR-EBZ | 功能描述:放大器 IC 开发工具 AD823AR-EBZ_A00676_EB-O8R-2Z RoHS:否 制造商:International Rectifier 产品:Demonstration Boards 类型:Power Amplifiers 工具用于评估:IR4302 工作电源电压:13 V to 23 V |
| AD823AR-REEL | 功能描述:IC OPAMP JFET R-R DUAL LN 8SOIC RoHS:否 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 标准包装:1 系列:- 放大器类型:通用 电路数:4 输出类型:满摆幅 转换速率:0.028 V/µs 增益带宽积:105kHz -3db带宽:- 电流 - 输入偏压:3nA 电压 - 输入偏移:100µV 电流 - 电源:3.3µA 电流 - 输出 / 通道:12mA 电压 - 电源，单路/双路(±):2.7 V ~ 12 V，±1.35 V ~ 6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:14-TSSOP（0.173"，4.40mm 宽） 供应商设备封装:14-TSSOP 包装:剪切带 (CT) 其它名称:OP481GRUZ-REELCT |
| AD823AR-REEL7 | 功能描述:IC OPAMP JFET R-R DUAL LN 8SOIC RoHS:否 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 标准包装:73 系列:Over-The-Top® 放大器类型:通用 电路数:4 输出类型:满摆幅 转换速率:0.07 V/µs 增益带宽积:200kHz -3db带宽:- 电流 - 输入偏压:1nA 电压 - 输入偏移:285µV 电流 - 电源:50µA 电流 - 输出 / 通道:25mA 电压 - 电源，单路/双路(±):2 V ~ 44 V，±1 V ~ 22 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:16-WFDFN 裸露焊盘 供应商设备封装:16-DFN-EP（5x3） 包装:管件 |
| AD823ARZ | 功能描述:IC OPAMP JFET R-R DUAL LN 8SOIC RoHS:是 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 标准包装:2,500 系列:- 放大器类型:通用 电路数:4 输出类型:- 转换速率:0.6 V/µs 增益带宽积:1MHz -3db带宽:- 电流 - 输入偏压:45nA 电压 - 输入偏移:2000µV 电流 - 电源:1.4mA 电流 - 输出 / 通道:40mA 电压 - 电源，单路/双路(±):3 V ~ 32 V，±1.5 V ~ 16 V 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:14-TSSOP（0.173"，4.40mm 宽） 供应商设备封装:14-TSSOP 包装:带卷 (TR) 其它名称:LM324ADTBR2G-NDLM324ADTBR2GOSTR |
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