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参数资料
| 型号： | AD73311 |
| 厂商： | Analog Devices, Inc. |
| 英文描述： | Low Cost, Low Power CMOS General Purpose Analog Front End Processor(低成本、低功耗、CMOS通用模拟前端处理器) |
| 中文描述： | 低成本，低功耗CMOS通用模拟前端处理器（低成本，低功耗，的CMOS通用模拟前端处理器） |
| 文件页数： | 24/36页 |
| 文件大小： | 290K |
| 代理商： | AD73311 |
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AD73311
–24–
REV. A
It is also possible to subsample the DAC—update at a lower rate
than the sampling rate—to reduce the overhead on the DSP.
This, however, results in imaging of the subsampled bandwidth
into the normal bandwidth, which implies that higher perfor-
mance external anti-imaging filtering must be used to eliminate
the images.
The interpolator input also provides a minimum group delay
realization in situations where that is critical. Further reduction
in group delay is possible by accessing the digital sigma-delta
input at the expense of lower attenuation of images due to any
repetition of input samples. Figure 21 shows the spectral
response of the decoder being sampled at 64 kHz with its inter-
polator bypassed.
FREQUENCY – kHz
0
–1400
32
5
10
15
20
25
30
–20
–60
–80
–100
–120
–40
d
S/N+D = 58.557732
Figure 21. FFT (DAC 64 kHz Sampling—Interpolator
Bypassed)
Decoder Group Delay
The interpolator roll-off is mainly due to its sync-cubed function
characteristic, which has an inherent group delay given by the
equation.
Group Delay (Interpolator) =
Order
×
(
L
– 1)/2)
×
Tint
where:
Order
is the interpolator order (= 3),
L
is the interpolation factor (= 32) and
Tint
is the interpolation sample interval
(= 1/2.048e6)
=> Group Delay (Interpolator)
= 3*(32-1)/2*(1/2.048e6)
= 22.7
μ
s
The analog section has a group delay of approximately 25
μ
s.
DESIGN CONSIDERATIONS
Analog Input
The analog input signal to the codec can be dc coupled, pro-
vided that the dc bias level of the input signal is the same as the
internal reference level (REFOUT). Figure 22 shows the recom-
mended differential input circuit for the AD73311’s analog
input pins (VIN). The circuit of Figure 22 implements first-
order low-pass filters with a 3 dB point at 34 kHz; these are the
only filters that must be implemented external to the AD73311
to prevent aliasing of the sampled signal. Since the codec’s ADC
uses a highly oversampled approach that transfers the bulk of
the antialiasing filtering into the digital domain, the off-chip
antialiasing filter need only be of a low order. It is recommended
that for optimum performance that the capacitors used for the
antialiasing filter be of high quality dielectric (NPO).
REFCAP
VOLTAGE
REFERENCE
0.1
m
F
REFOUT
TO INPUT BIAS
CIRCUITRY
100
V
100
V
V
IN
0.047
m
F
0.047
m
F
VINN
VINP
AD73311
Figure 22. Example Circuit for Differential Input
(DC Coupling)
The AD73311’s on-chip 38 dB preamplifier can be enabled when
there is not enough gain in the input circuit; the preamplifier is
configured by bits IGS0–2 of CRD. The total gain must be
configured to ensure that a full-scale input signal produces a
signal level at the input to the sigma-delta modulator of the
ADC that does not exceed the maximum input range.
The dc biasing of the analog input signal is accomplished with
an on-chip voltage reference. If the input signal is not biased at
the internal reference level (via REFOUT), then it must be ac-
coupled with external coupling capacitors. C
IN
should be 0.1
μ
F
or larger. The dc biasing of the input can then be accomplished
using resistors to REFOUT as in Figure 23.
REFCAP
VOLTAGE
REFERENCE
0.1
m
F
REFOUT
TO INPUT BIAS
CIRCUITRY
100
V
100
V
V
IN
CIN
CIN
0.047
m
F
0.047
m
F
VINN
VINP
10k
V
10k
V
AD73311
Figure 23. Example Circuit for Differential Input
(AC Coupling)
相关PDF资料 |
PDF描述 |
|---|---|
| AD73322LARU | Low Cost, Low Power CMOS General-Purpose Dual Analog Front End |
| AD73322AR | Low Cost, Low Power CMOS General-Purpose Dual Analog Front End |
| AD73322AST | Low Cost, Low Power CMOS General-Purpose Dual Analog Front End |
| AD73322LAR | Low Cost, Low Power CMOS General-Purpose Dual Analog Front End |
| AD73322LAST | Low Cost, Low Power CMOS General-Purpose Dual Analog Front End |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AD73311AR | 制造商:Analog Devices 功能描述:Audio Codec 1ADC / 1DAC 16-Bit 20-Pin SOIC W 制造商:Rochester Electronics LLC 功能描述:SPEECH & TELEPHONY CODEC I.C. - Bulk 制造商:Analog Devices 功能描述:SPEECH/TELEPHONY CODEC SMD 73311 |
| AD73311AR-REEL | 制造商:Analog Devices 功能描述:Audio Codec 1ADC / 1DAC 16-Bit 20-Pin SOIC W T/R |
| AD73311ARS | 制造商:Analog Devices 功能描述:Audio Codec 1ADC / 1DAC 16-Bit 20-Pin SSOP |
| AD73311ARS-REEL | 制造商:Analog Devices 功能描述:Audio Codec 1ADC / 1DAC 16-Bit 20-Pin SSOP T/R 制造商:Rochester Electronics LLC 功能描述:SPEECH & TELEPHONY CODEC I.C. - Tape and Reel |
| AD73311ARSZ | 功能描述:IC ANALOG FRONT END 20-SSOP RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模拟前端 (AFE) 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 位数:- 通道数:2 功率（瓦特）:- 电压 - 电源，模拟:3 V ~ 3.6 V 电压 - 电源，数字:3 V ~ 3.6 V 封装/外壳:32-VFQFN 裸露焊盘 供应商设备封装:32-QFN（5x5） 包装:带卷 (TR) |
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