參數(shù)資料
型號(hào): MAX1403EVL11
廠商: Maxim Integrated Products
文件頁(yè)數(shù): 22/36頁(yè)
文件大?。?/td> 0K
描述: EVAL KIT FOR MAX1403
產(chǎn)品培訓(xùn)模塊: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
標(biāo)準(zhǔn)包裝: 1
ADC 的數(shù)量: 1
位數(shù): 18
采樣率(每秒): 480
數(shù)據(jù)接口: 串行
輸入范圍: ±VREF/增益
在以下條件下的電源(標(biāo)準(zhǔn)): 16.9mW @ 480SPS
工作溫度: 0°C ~ 70°C
已用 IC / 零件: MAX1403
已供物品: 2 板,CD
MAX1403
+3V, 18-Bit, Low-Power, Multichannel,
Oversampling (Sigma-Delta) ADC
______________________________________________________________________________________
29
Digital Filter
The on-chip digital filter processes the 1-bit data
stream from the modulator using a SINC3 or SINC1 fil-
ter. The SINC filters are conceptually simple, efficient,
and extremely flexible, especially where variable reso-
lution and data rates are required. Also, the filter notch
positions are easily controlled since they are directly
related to the output data rate (1 / data word period).
The SINC1 function results in a faster settling response
while retaining the same frequency response notches
as the default SINC3 filter. This allows the filter to settle
faster at the expense of resolution and quantization
noise. The SINC1 filter settles in one data word period.
With 60Hz notches (60Hz data rate), the settling time
would be 1 / 60Hz or 16.7ms, whereas the SINC3 filter
would settle in 3 / 60Hz or 50ms. Toggle between these
filter responses using the FAST bit in the global setup
register. Use SINC1 mode for faster settling and switch
to SINC3 mode when full accuracy is required. Switch from
the SINC1 to SINC3 mode by resetting the FAST bit low.
The DRDY signal will go false and will be reasserted
when valid data is available, a minimum of three data-
word periods later.
The digital filter can be bypassed by setting the MDOUT
bit in the global setup register. When MDOUT = 1, the
raw output of the modulator is directly available at DOUT.
Filter Characteristics
The MAX1403 digital filter implements both a SINC1
(sinx/x) and SINC3 (sinx/x)3 lowpass filter function. The
transfer function for the SINC3 function is that of three
cascaded SINC1 filters described in the z-domain by:
and in the frequency domain by:
where N, the decimation factor, is the ratio of the modu-
lator frequency fM to the output frequency fN.
Figure 10 shows the filter frequency response. The
SINC3 characteristic cutoff frequency is 0.262 times the
first notch frequency. This results in a cutoff frequency
of 15.72Hz for a first filter notch frequency of 60Hz. The
response shown in Figure 10 is repeated at either side
of the digital filter’s sample frequency (fM) and at either
side of the related harmonics (2fM, 3fM, . . .).
The response of the SINC3 filter is similar to that of a
SINC1 (averaging filter) filter but with a sharper rolloff.
The output data rate for the digital filter corresponds
with the positioning of the first notch of the filter’s fre-
quency response. Therefore, for the plot of Figure 10
where the first notch of the filter is at 60Hz, the output
data rate is 60Hz. The notches of this (sinx/x)3 filter are
repeated at multiples of the first notch frequency. The
SINC3 filter provides an attenuation of better than
100dB at these notches.
Determine the cutoff frequency of the digital filter by the
value loaded into CLK, X2CLK, MF1, MF0, FS1, and FS0
in the global setup register. Programming a different
cutoff frequency with FS0 and FS1 does not alter the
profile of the filter response; it changes the frequency of
the notches. For example, Figure 11 shows a cutoff fre-
quency of 13.1Hz and a first notch frequency of 50Hz.
For step changes at the input, a settling time must be
allowed before valid data can be read. The settling time
depends upon the output data rate chosen for the filter.
The settling time of the SINC3 filter to a full-scale step
input can be up to four-times the output data period.
For a synchronized step input (using the FSYNC func-
tion or the internal scanning logic), the settling time is
three-times the output data period.
H(f)
1
N
sin N
f
sin
f
M
3
=
π
H(z)
1
N
1
z
1 – z
N
1
3
=
-160
-120
-140
-100
-80
-60
-20
-40
0
406080
20
100 120 140 160 180 200
FREQUENCY (Hz)
GAIN
(dB)
fCLKIN = 2.4576MHz
MF1, 0 = 0
FS1, 0 = 1
fN = 60Hz
Figure 10. Frequency Response of the SINC3 Filter (Notch at
60Hz)
相關(guān)PDF資料
PDF描述
AD586KRZ-REEL7 IC VREF SERIES PREC 5V 8-SOIC
MAX1280EVC16 EVAL KIT FOR MAX1280
LGU2G221MELA CAP ALUM 220UF 400V 20% SNAP
MAX1284EVC16 EVALUATION SYSTEM FOR MAX1284
381LX682M025J012 CAP ALUM 6800UF 25V 20% SNAP
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX1403EVSYSTEM 制造商:Maxim Integrated Products 功能描述:EVALUATION SYSTEM FOR THE MAX1403 - Boxed Product (Development Kits)
MAX1406C/D 功能描述:RS-232接口集成電路 RoHS:否 制造商:Exar 數(shù)據(jù)速率:52 Mbps 工作電源電壓:5 V 電源電流:300 mA 工作溫度范圍:- 40 C to + 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:LQFP-100 封裝:
MAX1406CAE 功能描述:RS-232接口集成電路 RoHS:否 制造商:Exar 數(shù)據(jù)速率:52 Mbps 工作電源電壓:5 V 電源電流:300 mA 工作溫度范圍:- 40 C to + 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:LQFP-100 封裝:
MAX1406CAE+ 功能描述:RS-232接口集成電路 15kV ESD-Protected 230kbps RS-232 LD/Rc RoHS:否 制造商:Exar 數(shù)據(jù)速率:52 Mbps 工作電源電壓:5 V 電源電流:300 mA 工作溫度范圍:- 40 C to + 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:LQFP-100 封裝:
MAX1406CAE+T 功能描述:RS-232接口集成電路 15kV ESD-Protected 230kbps RS-232 LD/Rc RoHS:否 制造商:Exar 數(shù)據(jù)速率:52 Mbps 工作電源電壓:5 V 電源電流:300 mA 工作溫度范圍:- 40 C to + 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:LQFP-100 封裝: