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参数资料
| 型号： | LTC2272CUJ |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | ADC |
| 英文描述： | 1-CH 16-BIT PROPRIETARY METHOD ADC, SERIAL ACCESS, PQCC40 |
| 封装： | 6 X 6 MM, PLASTIC, QFN-40 |
| 文件页数： | 16/44页 |
| 文件大小： | 767K |
| 代理商： | LTC2272CUJ |
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LTC2273/LTC2272
23
22732fa
APPLICATIONS INFORMATION
INPUT DRIVE CIRCUITS
Input Filtering
A rst order RC lowpass lter at the input of the ADC
can serve two functions: limit the noise from input cir-
cuitry and provide isolation from ADC S/H switching. The
LTC2273/LTC2272 have very broadband S/H circuits, DC
to 700MHz; it can be used in a wide range of applications;
therefore, it is not possible to provide a single recom-
mended RC lter.
Figures 3, 4a and 4b show three examples of input RC
ltering at three ranges of input frequencies. In general,
it is desirable to make the capacitors as large as can be
tolerated—this will help suppress random noise as well
as noise coupled from the digital circuitry. The LTC2273/
LTC2272 do not require any input lter to achieve data sheet
specications; however, no ltering will put more stringent
noise requirements on the input drive circuitry.
Transformer Coupled Circuits
Figure 3 shows the LTC2273/LTC2272 being driven by
an RF transformer with a center-tapped secondary. The
secondary center tap is DC biased with VCM, setting the
ADC input signal at its optimum DC level. Figure 3 shows
a 1:1 turns ratio transformer. Other turns ratios can be
used; however, as the turns ratio increases so does the
impedance seen by the ADC. Source impedance greater
than 50
Ω can reduce the input bandwidth and increase
high frequency distortion. A disadvantage of using a
transformer is the loss of low frequency response. Most
small RF transformers have poor performance at frequen-
cies below 1MHz.
Center-tapped transformers provide a convenient means
of DC biasing the secondary; however, they often show
poor balance at high input frequencies, resulting in large
2nd order harmonics.
Figure 4a shows transformer coupling using a transmis-
sion line balun transformer. This type of transformer has
much better high frequency response and balance than
ux coupled center tap transformers. Coupling capacitors
are added at the ground and input primary terminals to
allow the secondary terminals to be biased at 1.25V. Figure
4b shows the same circuit with components suitable for
higher input frequencies.
0.1μF
AIN
+
AIN
–
4.7pF
2.2μF
4.7pF
VCM
LTC2273/
LTC2272
ANALOG
INPUT
0.1μF
T1
1:1
T1 = MA/COM ETC1-1-13
RESISTORS, CAPACITORS
ARE 0402 PACKAGE SIZE
EXCEPT 2.2μF
22732 F04a
5Ω
10Ω
25Ω
10Ω
5Ω
Figure 4a. Using a Transmission Line Balun Transformer.
Recommended for Input Frequencies from 100MHz to 250MHz
0.1μF
AIN
+
AIN
–
2.2μF
2.2pF
VCM
LTC2273/
LTC2272
ANALOG
INPUT
0.1μF
T1
1:1
T1 = MA/COM ETC1-1-13
RESISTORS, CAPACITORS
ARE 0402 PACKAGE SIZE
EXCEPT 2.2μF
22732 F04b
5Ω
25Ω
5Ω
Figure 4b. Using a Transmission Line Balun Transformer.
Recommended for Input Frequencies from 250MHz to 500MHz
Figure 3. Single-Ended to Differential Conversion
Using a Transformer. Recommended for Input
Frequencies from 5MHz to 150MHz
35Ω
50Ω
35Ω
10Ω
5Ω
0.1μF
AIN
+
AIN
–
8.2pF
2.2μF
8.2pF
VCM
LTC2273/
LTC2272
T1
T1 = MA/COM ETC1-1T
RESISTORS, CAPACITORS
ARE 0402 PACKAGE SIZE
EXCEPT 2.2μF
22732 F03
相关PDF资料 |
PDF描述 |
|---|---|
| LTC2273CUJ | 1-CH 16-BIT PROPRIETARY METHOD ADC, SERIAL ACCESS, PQCC40 |
| LTC2272IUJ#TR | 1-CH 16-BIT PROPRIETARY METHOD ADC, SERIAL ACCESS, PQCC40 |
| LTC2273IUJ#TR | 1-CH 16-BIT PROPRIETARY METHOD ADC, SERIAL ACCESS, PQCC40 |
| LTC2273IUJ | 1-CH 16-BIT PROPRIETARY METHOD ADC, SERIAL ACCESS, PQCC40 |
| LTC2274CUJ#TR | 1-CH 16-BIT PROPRIETARY METHOD ADC, SERIAL ACCESS, PQCC40 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC2272CUJ#PBF | 制造商:Linear Technology 功能描述:ADC Single Pipelined 65Msps 16-bit Serial 40-Pin QFN EP 制造商:Linear Technology 功能描述:IC ADC 16BIT 65MSPS 40-QFN 制造商:Linear Technology 功能描述:A/D Converter IC 制造商:Linear Technology 功能描述:IC, ADC, 16BIT, 65MSPS, QFN-40; Resolution (Bits):16bit; Sampling Rate:65MSPS; Supply Voltage Type:Single; Supply Voltage Min:3.135V; Supply Voltage Max:3.465V; Supply Current:300mA; Digital IC Case Style:QFN; No. of Pins:40 ;RoHS Compliant: Yes |
| LTC2272CUJ#TRPBF | 制造商:Linear Technology 功能描述:ADC Single Pipelined 65Msps 16-bit Serial 40-Pin QFN EP T/R 制造商:Linear Technology 功能描述:IC ADC 16BIT 65MSPS 40-QFN |
| LTC2272CUJ-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:16-Bit, 80Msps/65Msps Serial Output ADC |
| LTC2272CUJ-TR | 制造商:LINER 制造商全称:Linear Technology 功能描述:16-Bit, 80Msps/65Msps Serial Output ADC |
| LTC2272CUJ-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:16-Bit, 80Msps/65Msps Serial Output ADC |
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