參數(shù)資料
型號(hào): AD9273BSVZ-50
廠商: Analog Devices Inc
文件頁數(shù): 17/48頁
文件大小: 0K
描述: IC ADC ASD OCTAL 50MSPS 100-TQFP
標(biāo)準(zhǔn)包裝: 1
類型: AAF,ADC,交叉點(diǎn)開關(guān),LNA,VGA
分辨率(位): 12 b
采樣率(每秒): 50M
數(shù)據(jù)接口: 串行,SPI?
電壓電源: 模擬和數(shù)字
電源電壓: 1.8V,3V
工作溫度: -40°C ~ 85°C
安裝類型: 表面貼裝
封裝/外殼: 100-TQFP 裸露焊盤
供應(yīng)商設(shè)備封裝: 100-TQFP-EP(14x14)
包裝: 托盤
產(chǎn)品目錄頁面: 780 (CN2011-ZH PDF)
AD9273
Rev. B | Page 24 of 48
LNA Noise
The short-circuit noise voltage (input-referred noise) is an impor-
tant limit on system performance. The short-circuit input-referred
noise voltage for the LNA is 1.4 nV/√Hz at a gain of 21.3 dB,
including the VGA noise at a VGA postamp gain of 27 dB. These
measurements, which were taken without a feedback resistor,
provide the basis for calculating the input noise and noise figure
(NF) performance of the configurations shown in Figure 41.
VOUT
UNTERMINATED
+
LI-x
RIN
RS
VOUT
RESISTIVE TERMINATION
+
LI-x
RIN
RS
VOUT
ACTIVE IMPEDANCE MATCH
+
LI-x
RIN
RFB
1 + A/2
RS
RIN =
0
70
30
-10
4
Figure 41. Input Configurations
Figure 42 and Figure 43 are simulations of noise figure vs. source
resistance (RS) results using these configurations and an input-
referred noise voltage of 6 nV/√Hz for the VGA. Unterminated
(RFB = ∞) operation exhibits the lowest equivalent input noise
and noise figure. Figure 43 shows the noise figure vs. RS rising at
low RS—where the LNA voltage noise is large compared with the
source noise—and at high RS due to the noise contribution from
RFB. The lowest NF is achieved when RS matches RIN.
The main purpose of input impedance matching is to improve the
transient response of the system. With resistive termination, the
input noise increases due to the thermal noise of the matching
resistor and the increased contribution of the LNA’s input
voltage noise generator. With active impedance matching,
however, the contributions of both are smaller (by a factor of
1/(1 + LNA Gain)) than they would be for resistive termination.
Figure 42 shows the relative noise figure performance. In this
graph, the input impedance was swept with RS to preserve the
match at each point. The noise figures for a source impedance of
50 Ω are 7.3 dB, 4.2 dB, and 2.8 dB for the resistive termination,
active termination, and unterminated configurations, respectively.
The noise figures for 200 Ω are 4.5 dB, 1.7 dB, and 1.0 dB,
respectively.
Figure 43 shows the noise figure as it relates to RS for various values
of RIN, which is helpful for design purposes.
10
100
1k
0
1.5
3.0
4.5
6.0
7.5
9.0
10.5
12.0
RS ()
NO
IS
E
F
IG
UR
E
(
d
B)
07
03
0-
18
2
UNTERMINATED
SHUNT TERMINATION
ACTIVE
TERMINATION
Figure 42. Noise Figure vs. RS for Shunt Termination,
Active Termination Matched, and Unterminated Inputs, VGAIN = 0.8 V
10
100
1k
0
1.5
3.0
4.5
6.0
7.5
9.0
10.5
12.0
RS ()
NO
IS
E
F
IG
UR
E
(
d
B)
07
03
0-
18
3
UNTERMINATED
RIN = 200
RIN = 100
RIN = 75
RIN = 50
Figure 43. Noise Figure vs. RS for Various Fixed Values of RIN,
Active Termination Matched Inputs, VGAIN = 0.8 V
相關(guān)PDF資料
PDF描述
AD9272BSVZ-40 IC ADC OCT 12BIT 40MSPS 100-TQFP
VE-B4J-MY-S CONVERTER MOD DC/DC 36V 50W
MAX199BCNI+ IC DAS 12BIT 8CH 28-DIP
VE-B44-MY-S CONVERTER MOD DC/DC 48V 50W
MS3124P22-55S CONN RCPT 55POS JAM NUT W/SCKT
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AD9273BSVZRL-25 功能描述:模數(shù)轉(zhuǎn)換器 - ADC 12Bit 25 MSPS Octal ADC RoHS:否 制造商:Analog Devices 通道數(shù)量: 結(jié)構(gòu): 轉(zhuǎn)換速率: 分辨率: 輸入類型: 信噪比: 接口類型: 工作電源電壓: 最大工作溫度: 安裝風(fēng)格: 封裝 / 箱體:
AD9273BSVZRL-40 功能描述:模數(shù)轉(zhuǎn)換器 - ADC 12Bit 40 MSPS Octal ADC RoHS:否 制造商:Analog Devices 通道數(shù)量: 結(jié)構(gòu): 轉(zhuǎn)換速率: 分辨率: 輸入類型: 信噪比: 接口類型: 工作電源電壓: 最大工作溫度: 安裝風(fēng)格: 封裝 / 箱體:
AD9273BSVZRL-50 功能描述:模數(shù)轉(zhuǎn)換器 - ADC 12Bit 50 MSPS Octal ADC RoHS:否 制造商:Analog Devices 通道數(shù)量: 結(jié)構(gòu): 轉(zhuǎn)換速率: 分辨率: 輸入類型: 信噪比: 接口類型: 工作電源電壓: 最大工作溫度: 安裝風(fēng)格: 封裝 / 箱體:
AD9273XBCZ 功能描述:IC ADC 制造商:analog devices inc. 系列:* 零件狀態(tài):上次購買時(shí)間 標(biāo)準(zhǔn)包裝:1
AD9276 制造商:AD 制造商全稱:Analog Devices 功能描述:Octal LNA/VGA/AAF/12-Bit ADC and CW I/Q Demodulator