数据搜索系统,热门电子元器件搜索
  Chinese  ▼
ALLDATASHEETCN.COM

X  

AD7475BR 数据表(PDF) 10 Page - Analog Devices

部件名 AD7475BR
功能描述  1 MSPS, 12-Bit ADCs
Download  16 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
制造商  AD [Analog Devices]
网页  http://www.analog.com
标志 AD - Analog Devices

AD7475BR 数据表(HTML) 10 Page - Analog Devices

Back Button AD7475BR Datasheet HTML 6Page - Analog Devices AD7475BR Datasheet HTML 7Page - Analog Devices AD7475BR Datasheet HTML 8Page - Analog Devices AD7475BR Datasheet HTML 9Page - Analog Devices AD7475BR Datasheet HTML 10Page - Analog Devices AD7475BR Datasheet HTML 11Page - Analog Devices AD7475BR Datasheet HTML 12Page - Analog Devices AD7475BR Datasheet HTML 13Page - Analog Devices AD7475BR Datasheet HTML 14Page - Analog Devices Next Button
Zoom Inzoom in Zoom Outzoom out
 10 / 16 page
background image
REV. A
AD7475/AD7495
–10–
When no amplifier is used to drive the analog input, the source
impedance should be limited to low values. The maximum source
impedance will depend on the amount of total harmonic distortion
(THD) that can be tolerated. The THD will increase as the source
impedance increases and performance will degrade. Figure 10
shows a graph of the total harmonic distortion versus source
impedance for various analog input frequencies.
SOURCE IMPEDANCE – Ohms
–90
1
100
–80
–70
–60
–50
10000
–40
fIN = 500kHz
fIN = 10kHz
fIN = 100kHz
fIN = 200kHz
10
1000
–30
–20
–10
Figure 10. THD vs. Source Impedance for Various Ana-
log Input Frequencies
Figure 11 shows a graph of total harmonic distortion versus analog
Input frequency for various supply voltages while sampling at
1 MSPS with an SCLK of 20 MHz.
INPUT FREQUENCY – kHz
10
100
–95
–93
–91
–87
1000
–85
VDD = VDRIVE = 3.60V
VDD = VDRIVE = 2.70V
VDD = VDRIVE = 5.25V
VDD = VDRIVE = 4.75V
–83
–81
–79
–77
–75
–89
Figure 11. THD vs. Analog Input Frequency for Various
Supply Voltages
Digital Inputs
The digital inputs applied to the AD7475/AD7495 are not limited
by the maximum ratings which limit the analog inputs. Instead,
the digital inputs applied can go to 7 V and are not restricted by
the VDD + 0.3 V limit as on the analog inputs.
Another advantage of SCLK and
CS not being restricted by the
VDD + 0.3 V limit is the fact that power supply sequencing issues
are avoided. If
CS or SCLK are applied before V
DD, there is no
risk of latch-up as there would be on the analog inputs if a
signal greater than 0.3 V were applied prior to VDD.
VDRIVE
The AD7475/AD7495 also has the VDRIVE feature. VDRIVE
controls the voltage at which the serial interface operates. VDRIVE
allows the ADC to easily interface to both 3 V and 5 V processors.
For example, if the AD7475/AD7495 were operated with a VDD
of 5 V, and the VDRIVE pin could be powered from a 3 V supply.
The AD7475/AD7495 has better dynamic performance with a
VDD of 5 V while still being able to interface to 3 V digital parts.
Care should be taken to ensure VDRIVE does not exceed VDD by
more than 0.3 V. (See Absolute Maximum Ratings.)
Reference Section
An external reference source should be used to supply the 2.5 V
reference to the AD7475. Errors in the reference source will result
in gain errors in the AD7475 transfer function and will add the
specified full-scale errors on the part. A capacitor of at least 0.1
µF
should be placed on the REF IN pin. Suitable reference sources
for the AD7475 include the AD780, the AD680, and the AD1852.
The AD7495 contains an on-chip 2.5 V reference. As shown in
Figure 12, the voltage that appears at the REF OUT pin is inter-
nally buffered before being applied to the ADC, the output
impedance of this buffer is typically 10
Ω. The reference is capable
of sourcing up to 2 mA. The REF OUT pin should be decoupled
to AGND using a 100 nF or greater capacitor.
If the 2.5 V internal reference is to be used to drive another device
that is capable of glitching the reference at critical times, then the
reference will have to be buffered before driving the device. To
ensure optimum performance of the AD7495 it is recommended
that the Internal Reference not be over driven. If the use of an
external reference is required the AD7475 should be used.
V
REF OUT
25
40k
160k
Figure 12. AD7495 Reference Circuit
MODES OF OPERATION
The mode of operation of the AD7475/AD7495 is selected by
controlling the (logic) state of the
CS signal during a conversion.
There are three possible modes of operation, Normal Mode,
Partial Power-Down Mode, and Full Power-Down Mode. The
point at which
CS is pulled high after the conversion has been
initiated will determine which power-down mode, if any, the device
will enter. Similarly, if already in a power-down mode,
CS can
control whether the device will return to Normal operation or
remain in power-down. These modes of operation are designed to
provide flexible power management options. These options can be
chosen to optimize the power dissipation/throughput rate ratio for
differing application requirements.
Normal Mode
This mode is intended for fastest throughput rate performance as
the user does not have to worry about any power-up times with
the AD7475/AD7495 remaining fully powered all the time.
Figure 13 shows the general diagram of the operation of the
AD7475/AD7495 in this mode.
The conversion is initiated on the falling edge of
CS as described in
the Serial Interface section. To ensure the part remains fully pow-
ered up at all times,
CS must remain low until at least 10 SCLK
falling edges have elapsed after the falling edge of
CS. If CS is
brought high any time after the 10th SCLK falling edge, but


类似零件编号 - AD7475BR

制造商部件名数据表功能描述
logo
Analog Devices
AD7475BR AD-AD7475BR Datasheet
453Kb / 24P
   1 MSPS,12-Bit ADCs
REV. B
AD7475BR AD-AD7475BR Datasheet
453Kb / 24P
   1MSPS,12-Bit ADCs
REV. B
AD7475BR-REEL AD-AD7475BR-REEL Datasheet
453Kb / 24P
   1 MSPS,12-Bit ADCs
REV. B
AD7475BR-REEL AD-AD7475BR-REEL Datasheet
453Kb / 24P
   1MSPS,12-Bit ADCs
REV. B
AD7475BR-REEL7 AD-AD7475BR-REEL7 Datasheet
453Kb / 24P
   1 MSPS,12-Bit ADCs
REV. B
More results

类似说明 - AD7475BR

制造商部件名数据表功能描述
logo
Analog Devices
AD7475 AD-AD7475_V01 Datasheet
519Kb / 24P
   1 MSPS,12-Bit ADCs
Rev. D
AD7495ARZ AD-AD7495ARZ Datasheet
453Kb / 24P
   1 MSPS,12-Bit ADCs
REV. B
AD7908BRUZ AD-AD7908BRUZ Datasheet
456Kb / 32P
   8-Channel, 1 MSPS, 8-/10-/12-Bit ADCs
REV. D
EVAL-AD7922 AD-EVAL-AD7922_15 Datasheet
862Kb / 16P
   Evaluation Board for 1 MSPS, 2-Channel, 12-/10-Bit ADCs
REV. 0
EVAL-AD7912 AD-EVAL-AD7912_15 Datasheet
862Kb / 16P
   Evaluation Board for 1 MSPS, 2-Channel, 12-/10-Bit ADCs
REV. 0
AD7476 AD-AD7476_15 Datasheet
560Kb / 25P
   1 MSPS, 12-/10-/8-Bit ADCs in 6-Lead SOT-23
Rev. F
AD7478 AD-AD7478_15 Datasheet
560Kb / 25P
   1 MSPS, 12-/10-/8-Bit ADCs in 6-Lead SOT-23
Rev. F
AD7470 AD-AD7470_15 Datasheet
529Kb / 21P
   1.75 MSPS, 4 mW 10-Bit/12-Bit Parallel ADCs
REV. B
AD7470 AD-AD7470_03 Datasheet
325Kb / 20P
   1.75 MSPS, 4 mW 10-Bit/12-Bit Parallel ADCs
REV. B
AD7477AAKS AD-AD7477AAKS Datasheet
466Kb / 24P
   1 MSPS, 12-/10-/8-Bit ADCs in 6-Lead SOT-23
Rev. F
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16


数据表 下载

Go To PDF Page


链接网址




隐私政策
ALLDATASHEETCN.COM
ALLDATASHEET是否为您带来帮助?  [ DONATE ] 

关于 Alldatasheet   |   广告服务   |   联系我们   |   隐私政策   |   链接交换   |   制造商名单
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com