参数资料
型号: MAX7404CPA+
厂商: Maxim Integrated Products
文件页数: 12/12页
文件大小: 0K
描述: IC FILTER LOWPASS 8-DIP
产品培训模块: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
标准包装: 50
滤波器类型: 椭圆,低通开关电容器
频率 - 截止或中心: 10kHz
滤波器数: 1
滤波器阶数: 8th
电源电压: 2.7 V ~ 3.6 V
安装类型: 通孔
封装/外壳: 8-DIP(0.300",7.62mm)
供应商设备封装: 8-PDIP
包装: 管件
MAX7400/MAX7403/MAX7404/MAX7407
8th-Order, Lowpass, Elliptic,
Switched-Capacitor Filters
_______________________________________________________________________________________
9
Detailed Description
The MAX7400/MAX7403/MAX7404/MAX7407 family of
8th-order, lowpass filters provides sharp rolloff with
good stopband rejection. All parts operate with a
100:1 clock-to-corner frequency ratio and a 10kHz
maximum corner frequency. These devices accept a
single +5V (MAX7400/MAX7403) or +3V (MAX7404/
MAX7407) supply. Figure 1 shows the functional dia-
gram.
Most switched-capacitor filters (SFCs) are designed
with biquadratic sections. Each section implements two
filtering poles, and the sections can be cascaded to
produce higher-order filters. The advantage of this
approach is ease of design. However, this type of
design is highly sensitive to component variations if any
section’s Q is high. The MAX7400 family uses an alter-
native approach, which is to emulate a passive network
using switched-capacitor integrators with summing and
scaling. The passive network can be synthesized using
CAD programs or can be found in many filter books.
Figure 2 shows a basic 8th-order ladder elliptic filter
structure.
A switched-capacitor filter that emulates a passive lad-
der filter retains many of the same advantages. The
component sensitivity of a passive ladder filter is low
when compared to a cascaded biquadratic design,
because each component affects the entire filter shape
rather than a single pole-zero pair. In other words, a
mismatched component in a biquadratic design has a
concentrated error on its respective poles, while the
same mismatch in a ladder filter design spreads its
error over all poles.
Elliptic Characteristics
Lowpass, elliptic filters such as the MAX7400/MAX7403/
MAX7404/MAX7407 provide the steepest possible rolloff
with frequency of the four most common filter types
(Butterworth, Bessel, Chebyshev, and Elliptic). Figure 3
shows the 8th-order elliptic filter response. The high Q
value of the poles near the passband edge combined
with the stopband zeros allows for the sharp attenua-
tion characteristic of elliptic filters, making these
devices ideal for anti-aliasing and post-DAC filtering in
single-supply systems (see the
Anti-Aliasing and Post-
DAC Filtering section).
In the frequency domain, the first transmission zero
causes the filter’s amplitude to drop to a minimum level.
Beyond this zero, the response rises as the frequency
increases until the next transmission zero. The stopband
begins at the stopband frequency, fS. At frequencies
above fS, the filter’s gain does not exceed the gain at fS.
The corner frequency, fC, is defined as the point where
the filter output attenuation falls just below the passband
ripple. The transition ratio is defined as the ratio of the
stopband frequency to the corner frequency:
r = fS / fC
The MAX7400/MAX7404 have a transition ratio of 1.5
and a typical stopband rejection of 82dB. The
MAX7403/MAX7407 have a transition ratio of 1.2 (pro-
viding the steepest rolloff) and a typical stopband
rejection of 60dB.
2
INT
CLOCK
IN
1
COM
8
CLK
SHDN
7
4
5
6
3
VDD
OUT
OS
GND
BIAS
SCF
LOGIC
OFFSET
ADJ
MAX7400
MAX7403
MAX7404
MAX7407
VDD
Figure 1. Functional Diagram
C10
C11
C9
L3
L5
L7
C8
R2
C4
C2
VIN
+
-
V0
L1
R1
C6
Figure 2. 8th-Order Ladder Filter Network
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相关代理商/技术参数
参数描述
MAX7404CPA+ 功能描述:有源滤波器 8th-Order Lowpass Elliptic Filter RoHS:否 制造商:Maxim Integrated 通道数量:1 截止频率:150 KHz 电源电压-最大:11 V 电源电压-最小:4.74 V 最大工作温度:+ 85 C 安装风格:Through Hole 封装 / 箱体:PDIP N 封装:Tube
MAX7404CSA 功能描述:有源滤波器 RoHS:否 制造商:Maxim Integrated 通道数量:1 截止频率:150 KHz 电源电压-最大:11 V 电源电压-最小:4.74 V 最大工作温度:+ 85 C 安装风格:Through Hole 封装 / 箱体:PDIP N 封装:Tube
MAX7404CSA+ 功能描述:有源滤波器 8th-Order Lowpass Elliptic Filter RoHS:否 制造商:Maxim Integrated 通道数量:1 截止频率:150 KHz 电源电压-最大:11 V 电源电压-最小:4.74 V 最大工作温度:+ 85 C 安装风格:Through Hole 封装 / 箱体:PDIP N 封装:Tube
MAX7404CSA+T 功能描述:有源滤波器 8th-Order Lowpass Elliptic Filter RoHS:否 制造商:Maxim Integrated 通道数量:1 截止频率:150 KHz 电源电压-最大:11 V 电源电压-最小:4.74 V 最大工作温度:+ 85 C 安装风格:Through Hole 封装 / 箱体:PDIP N 封装:Tube
MAX7404CSA-T 功能描述:有源滤波器 RoHS:否 制造商:Maxim Integrated 通道数量:1 截止频率:150 KHz 电源电压-最大:11 V 电源电压-最小:4.74 V 最大工作温度:+ 85 C 安装风格:Through Hole 封装 / 箱体:PDIP N 封装:Tube