參數資料
型號: AD8009-EB
廠商: Analog Devices, Inc.
英文描述: 1 GHz, 5,500 V/us Low Distortion Amplifier
中文描述: 1千兆赫,5,500 V的/我們的低失真放大器
文件頁數: 11/12頁
文件大?。?/td> 229K
代理商: AD8009-EB
AD8009
–11–
REV. B
Driving a Capacitive Load
A capacitive load, like that presented by some A/D converters,
can sometimes be a challenge for an op amp to drive depending
on the architecture of the op amp. Most of the problem is
caused by the pole created by the output impedance of the op
amp and the capacitor that is driven. This creates extra phase
shift that can eventually cause the op amp to become unstable.
One way to prevent instability and improve settling time when
driving a capacitor is to insert a resistor in series between the op
amp output and the capacitor. The feedback resistor is still
connected directly to the output of the op amp, while the series
resistor provides some isolation of the capacitive load from the
op amp output.
10 F
+
0.1 F
0.001 F
10 F
+
0.1 F
0.001 F
AD8009
49.9
+5V
5V
3
2
4
R
T
R
S
C
L
50pF
2V
STEP
7
6
R
F
R
G
G = + 2: R
F
= 301 = R
G
G = + 10: R
F
= 200 , R
G
= 22.1
Figure 39. Capacitive Load Drive Circuit
Figure 39 shows such a circuit with an AD8009 driving a 50 pF
load. With R
S
= 0, the AD8009 circuit will be unstable. For a
gain of +2 and +10, it was found experimentally that setting R
S
to 42.2
will minimize the 0.1% settling time with a 2 V step at
the output. The 0.1% settling time was measured to be 40 ns with
this circuit.
For smaller capacitive loads, a smaller R
S
will yield optimal
settling time, while a larger R
S
will be required for larger
capacitive loads. Of course, a larger capacitance will always
require more time for settling to a given accuracy than a smaller
one, and this will be lengthened by the increase in R
S
required.
At best, a given RC combination will require about 7 time
constants by itself to settle to 0.1%, so a limit will be reached
where too large a capacitance cannot be driven by a given
op amp and still meet the system’s required settling time
specification.
相關PDF資料
PDF描述
AD8010 200 mA Output Current High Speed Amplifier
AD8010AN 200 mA Output Current High Speed Amplifier
AD8010AR 200 mA Output Current High Speed Amplifier
AD8010AR-REEL 200 mA Output Current High Speed Amplifier
AD8010AR-REEL7 200 mA Output Current High Speed Amplifier
相關代理商/技術參數
參數描述
AD8009JRT 制造商:未知廠家 制造商全稱:未知廠家 功能描述:1 GHz 5-500 V/micros Low Distortion Amplifier(234.18 k)
AD8009JRT-EBZ 功能描述:BOARD EVAL FOR AD8009 RoHS:是 類別:編程器,開發(fā)系統(tǒng) >> 評估板 - 運算放大器 系列:- 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:1 系列:-
AD8009JRT-R2 制造商:Analog Devices 功能描述:OP Amp Single Current Fdbk
AD8009JRT-REEL 制造商:Analog Devices 功能描述:OP Amp Single Current Fdbk ±6V/12V 5-Pin SOT-23 T/R
AD8009JRT-REEL7 功能描述:IC OPAMP CF LDIST 175MA SOT23-5 RoHS:否 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 標準包裝:2,500 系列:- 放大器類型:通用 電路數:1 輸出類型:滿擺幅 轉換速率:0.11 V/µs 增益帶寬積:350kHz -3db帶寬:- 電流 - 輸入偏壓:4nA 電壓 - 輸入偏移:20µV 電流 - 電源:260µA 電流 - 輸出 / 通道:20mA 電壓 - 電源,單路/雙路(±):2.7 V ~ 36 V,±1.35 V ~ 18 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC(0.154",3.90mm 寬) 供應商設備封裝:8-SO 包裝:帶卷 (TR)