参数资料
型号: AD8045ACPZ-REEL7
厂商: ANALOG DEVICES INC
元件分类: 运动控制电子
英文描述: 3 nV/Hz Ultralow Distortion, High Speed Op Amp
中文描述: OP-AMP, 1000 uV OFFSET-MAX, DSO8
封装: 3 X 3 MM, LEAD FREE, CSP-8
文件页数: 19/24页
文件大小: 474K
代理商: AD8045ACPZ-REEL7
AD8045
APPLICATIONS
LOW DISTORTION PINOUT
The AD8045 LFCSP package features Analog Devices new low
distortion pinout. The new pinout provides two advantages
over the traditional pinout. First, improved second harmonic
distortion performance, which is accomplished by the physical
separation of the noninverting input pin and the negative power
supply pin. Second, the simplification of the layout due to the
dedicated feedback pin and easy routing of the gain set resistor
back to the inverting input pin. This allows a compact layout,
which helps to minimize parasitics and increase stability.
Rev. A | Page 19 of 24
The traditional SOIC pinout has been slightly modified as well
to incorporate a dedicated feedback pin. Pin 1, previously a no
connect pin on the amplifier, is now a dedicated feedback pin. The
new pinout reduces parasitics and simplifies the board layout.
Existing applications that use the traditional SOIC pinout can
take full advantage of the outstanding performance offered by
the AD8045. An electrical insulator may be required if the SOIC
rests on the ground plane or other metal trace. This is covered
in more detail in the Exposed Paddle section of this data sheet.
In existing designs, which have Pin 1 tied to ground or to
another potential, simply lift Pin 1 of the AD8045 or remove the
potential on the Pin 1 solder pad. The designer does not need to
use the dedicated feedback pin to provide feedback for the
AD8045. The output pin of the AD8045 can still be used to pro-
vide feedback to the inverting input of the AD8045.
HIGH SPEED ADC DRIVER
When used as an ADC driver, the AD8045 offers results compa-
rable to transformers in distortion performance. Many ADC
applications require that the analog input signal be dc-coupled
and operate over a wide frequency range. Under these require-
ments, operational amplifiers are very effective interfaces to
ADCs. An op amp interface provides the ability to amplify and
level shift the input signal to be compatible with the input range
of the ADC. Unlike transformers, operational amplifiers can be
operated over a wide frequency range down to and including dc.
Figure 67 shows the AD8045 as a dc-coupled differential driver
for the
AD9244
, a 14-bit 65 MSPS ADC. The two amplifiers are
configured in noninverting and inverting modes. Both amplifi-
ers are set with a noise gain of +2 to provide better bandwidth
matching. The inverting amplifier is set for a gain of –1, while
the noninverting is set for a gain of +2. The noninverting input
is divided by 2 in order to normalize its output and make it
equal to the inverting output.
This dc-coupled differential driver is best suited for ±5 V
operation in which optimum distortion performance is required
and the input signal is ground referenced.
V
INA
V
INB
CML
AD9244
511
511
511
511
511
511
VIN
V
CML
– V
IN
AD8045
AD8045
0.1
μ
F
20pF
1
μ
F
0.1
μ
F
OP27
511
511
V
CML
+ V
IN
33
33
2.5k
100
0
Figure 67. High Speed ADC Driver
The outputs of the AD8045s are centered about the AD9244’s
common-mode range of 2.5 V. The common-mode reference
voltage from the AD9244 is buffered and filtered via the
OP27
and fed to the noninverting resistor network used in the level
shifting circuit.
The spurious-free dynamic range (SFDR) performance is
shown in Figure 68. Figure 69 shows a 50 MHz single-tone FFT
performance.
0
INPUT FREQUENCY (MHz)
100
1
10
S
120
100
80
60
40
20
0
AD8045
Figure 68. SFDR vs. Frequency
相关PDF资料
PDF描述
AD8045ARD 3 nV/Hz Ultralow Distortion, High Speed Op Amp
AD8045ARD-REEL 3 nV/Hz Ultralow Distortion, High Speed Op Amp
AD8045ARD-REEL7 3 nV/Hz Ultralow Distortion, High Speed Op Amp
AD8045ARDZ 3 nV/Hz Ultralow Distortion, High Speed Op Amp
AD8045ARDZ-REEL 3 nV/Hz Ultralow Distortion, High Speed Op Amp
相关代理商/技术参数
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AD8045AR 制造商:Analog Devices 功能描述:ULTRA-LOW DISTORTION HIGH SPEED AMPLIFIER - Bulk
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AD8045ARD-REEL 制造商:Analog Devices 功能描述:OP Amp Single Volt Fdbk 制造商:Analog Devices 功能描述:OP AMP SGL VOLT FDBK 6V/12V 8SOIC N EP - Tape and Reel
AD8045ARD-REEL7 制造商:Analog Devices 功能描述:OP Amp Single Volt Fdbk