參數(shù)資料
型號(hào)： AD9225ARZRL
廠商： Analog Devices Inc
文件頁(yè)數(shù)： 2/25頁(yè)
文件大?。?/td> 0K
描述： IC ADC 12BIT 25MSPS 28SOIC
標(biāo)準(zhǔn)包裝： 1,000
位數(shù)： 12
采樣率（每秒）： 25M
數(shù)據(jù)接口： 并聯(lián)
轉(zhuǎn)換器數(shù)目： 7
功率耗散（最大）： 373mW
電壓電源： 單電源
工作溫度： -40°C ~ 85°C
安裝類(lèi)型： 表面貼裝
封裝/外殼： 28-SOIC（0.295"，7.50mm 寬）
供應(yīng)商設(shè)備封裝： 28-SOIC W
包裝： 帶卷 (TR)
輸入數(shù)目和類(lèi)型： 2 個(gè)單端，雙極；1 個(gè)差分，單極
–10–
AD9225
REFERENCE OPERATION
The AD9225 contains an on-board band gap reference that
provides a pin strappable option to generate either a 1 V or 2 V
output. With the addition of two external resistors, the user can
generate reference voltages other than 1 V and 2 V. Another
alternative is to use an external reference for designs requiring
enhanced accuracy and/or drift performance. See Table II for
a summary of the pin strapping options for the AD9225 refer-
ence configurations.
Figure 5 shows a simplified model of the internal voltage
reference of the AD9225. A pin strappable reference amplifier
buffers a 1 V fixed reference. The output from the reference
amplifier, A1, appears on the VREF pin. The voltage on the
VREF pin determines the full-scale input span of the ADC.
This input span equals
Full-Scale Input Span = 2
VREF
The voltage appearing at the VREF pin as well as the state of
the internal reference amplifier, A1, are determined by the volt-
age appearing at the SENSE pin. The logic circuitry contains
two comparators that monitor the voltage at the SENSE pin.
The comparator with the lowest set point (approximately 0.3 V)
controls the position of the switch within the feedback path of
A1. If the SENSE pin is tied to AVSS (AGND), the switch is
connected to the internal resistor network thus providing a
VREF of 2.0 V. If the SENSE pin is tied to the VREF pin via
a short or resistor, the switch will connect to the SENSE pin.
This short will provide a VREF of 1.0 V. An external resistor
network will provide an alternative VREF between 1.0 V and
2.0 V. The other comparator controls internal circuitry that will
disable the reference amplifier if the SENSE pin is tied AVDD.
Disabling the reference amplifier allows the VREF pin to be
driven by an external voltage reference.
A2
5k
LOGIC
DISABLE
A2
6.25k
LOGIC
A1
DISABLE
A1
1V
TO
A/D
AD9225
CAPT
CAPB
VREF
SENSE
REFCOM
6.25k
Figure 5. Equivalent Reference Circuit
The actual reference voltages used by the internal circuitry of
the AD9225 appears on the CAPT and CAPB pins. For proper
operation when using the internal or an external reference, it is
necessary to add a capacitor network to decouple these pins.
Figure 6 shows the recommended decoupling network. This
capacitive network performs the following three functions: (1)
along with the reference amplifier, A2, it provides a low source
impedance over a large frequency range to drive the ADC inter-
nal circuitry, (2) it provides the necessary compensation for A2,
and (3) it bandlimits the noise contribution from the reference.
The turn-on time of the reference voltage appearing between
CAPT and CAPB is approximately 15 ms and should be evalu-
ated in any power-down mode of operation.
0.1 F
10 F
0.1 F
CAPT
CAPB
AD9225
Figure 6. Recommended CAPT/CAPB
Decoupling Network
The ADC’s input span may be varied dynamically by changing the
differential reference voltage appearing across CAPT and CAPB
symmetrically around 2.5 V (i.e., midsupply). To change the refer-
ence at speeds beyond the capabilities of A2, it will be necessary to
drive CAPT and CAPB with two high speed, low noise amplifiers.
In this case, both internal amplifiers (i.e., A1 and A2) must be
disabled by connecting SENSE to AVDD, connecting VREF to
AVSS and removing the capacitive decoupling network. The exter-
nal voltages applied to CAPT and CAPB must be 2.0 V + Input
Span/4 and 2.0 V – Input Span/4, respectively, in which the input
span can be varied between 2 V and 4 V. Note that those samples
within the pipeline ADC during any reference transition will be
corrupted and should be discarded.
DRIVING THE ANALOG INPUTS
The AD9225 has a highly flexible input structure allowing it to
interface with single ended or differential input interface cir-
cuitry. The applications shown in this section and the Reference
Configurations section along with the information presented in
the Input and Reference Overview give examples of single-
ended and differential operation. Refer to Tables I and II for a
list of the different possible input and reference configurations
and their associated figures in the data sheet.
The optimum mode of operation, analog input range, and asso-
ciated interface circuitry will be determined by the particular
applications performance requirements as well as power supply
options. For example, a dc-coupled single-ended input would
be appropriate for most data acquisition and imaging applica-
tions. Many communication applications, which require a
dc-coupled input for proper demodulation, can take advantage
of the excellent single-ended distortion performance of the
AD9225. The input span should be configured so the system’s
performance objectives and the headroom requirements of the
driving op amp are simultaneously met.
Rev. C
相關(guān)PDF資料
PDF描述
LTC2857CDD-1#PBF IC TXRX RS485/RS422 8-DFN
AD9225ARSZRL IC ADC 12BIT 25MSPS 28SSOP
VE-26K-CU-F3 CONVERTER MOD DC/DC 40V 200W
LTC2851CMS8#PBF IC TXRX RS485 20MBPS 8-MSOP
T 3650 000 CONN MALE 14POS CABLE MNT GOLD
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AD9225-EB 制造商:Analog Devices 功能描述: 制造商:Analog Devices 功能描述:DEV TOOLS, EVAL BD FOR AD9225 - Bulk
AD9226 制造商:AD 制造商全稱(chēng):Analog Devices 功能描述:Complete 12-Bit, 65 MSPS ADC Converter
AD9226_01 制造商:AD 制造商全稱(chēng):Analog Devices 功能描述:Complete 12-Bit, 65 MSPS ADC Converter
AD9226ARS 功能描述:IC ADC 12BIT 65MSPS 28-SSOP RoHS:否 類(lèi)別:集成電路 (IC) >> 數(shù)據(jù)采集 - 模數(shù)轉(zhuǎn)換器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,500 系列:- 位數(shù):12 采樣率（每秒）:3M 數(shù)據(jù)接口:- 轉(zhuǎn)換器數(shù)目:- 功率耗散（最大）:- 電壓電源:- 工作溫度:- 安裝類(lèi)型:表面貼裝 封裝/外殼:SOT-23-6 供應(yīng)商設(shè)備封裝:SOT-23-6 包裝:帶卷 (TR) 輸入數(shù)目和類(lèi)型:-
AD9226ARSRL 功能描述:IC ADC 12BIT 65MSPS 28-SSOP RoHS:否 類(lèi)別:集成電路 (IC) >> 數(shù)據(jù)采集 - 模數(shù)轉(zhuǎn)換器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:2,500 系列:- 位數(shù):12 采樣率（每秒）:3M 數(shù)據(jù)接口:- 轉(zhuǎn)換器數(shù)目:- 功率耗散（最大）:- 電壓電源:- 工作溫度:- 安裝類(lèi)型:表面貼裝 封裝/外殼:SOT-23-6 供應(yīng)商設(shè)備封裝:SOT-23-6 包裝:帶卷 (TR) 輸入數(shù)目和類(lèi)型:-
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫(xiě)一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*