参数资料
型号: MAX7408CUA+
厂商: Maxim Integrated Products
文件页数: 12/12页
文件大小: 0K
描述: IC FILTER LOWPASS 5TH 8UMAX
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: 15kHz
滤波器数: 1
滤波器阶数: 5th
电源电压: 4.5 V ~ 5.5 V
安装类型: 表面贴装
封装/外壳: 8-TSSOP,8-MSOP(0.118",3.00mm 宽)
供应商设备封装: 8-uMAX
包装: 管件
配用: MAXFILTERBRD+-ND - BOARD EVAL MAX7408/7415/418-7425
MAX7408/MAX7411/MAX7412/MAX7415
5th-Order, Lowpass, Elliptic,
Switched-Capacitor Filters
_______________________________________________________________________________________
9
Clock Signal
External Clock
These SCFs are designed for use with external clocks
that have a 40% to 60% duty cycle. When using an
external clock, drive the CLK pin with a CMOS gate
powered from 0 to VDD. Varying the rate of the external
clock adjusts the corner frequency of the filter:
Internal Clock
When using the internal oscillator, the capacitance
(COSC) on CLK determines the oscillator frequency:
Since COSC is in the low picofarads, minimize the stray
capacitance at CLK so that it does not affect the inter-
nal oscillator frequency. Varying the rate of the internal
oscillator adjusts the filter’s corner frequency by a
100:1 clock-to-corner frequency ratio. For example, an
internal oscillator frequency of 100kHz produces a
nominal corner frequency of 1kHz.
Input Impedance vs. Clock Frequencies
The MAX7408/MAX7411/MAX7412/MAX7415’s input
impedance is effectively that of a switched-capacitor
resistor (see the following equation), and is inversely
proportional to frequency. The input impedance values
determined by the equation represent the average input
impedance, since the input current is not continuous. As
a rule, use a driver with an output resistance less than
10% of the filter’s input impedance.
Estimate the input impedance of the filter by using the
following formula:
where fCLK = clock frequency and CIN = 1pF.
Low-Power Shutdown Mode
The MAX7408/MAX7411/MAX7412/MAX7415 have a
shutdown mode that is activated by driving SHDN low.
In shutdown mode, the filter supply current reduces to
0.2A, and the output of the filter becomes high imped-
ance. For normal operation, drive SHDN high or con-
nect to VDD.
Applications Information
Offset (OS) and Common-Mode (COM)
Input Adjustment
COM sets the common-mode input voltage and is
biased at mid-supply with an internal resistor-divider. If
the application does not require offset adjustment, con-
nect OS to COM. For applications where offset adjust-
ment is required, apply an external bias voltage
through a resistor-divider network to OS, as shown in
Figure 3. For applications that require DC level shifting,
adjust OS with respect to COM. (Note: Do not leave OS
unconnected.) The output voltage is represented by
these equations:
where (VIN - VCOM) is lowpass filtered by the SCF and
OS is added at the output stage. See the
Electrical
VV
V
typical
OUT
IN
COM
OS
COM
DD
(
)
()
=
+
=
2
Z
1
(f
C )
IN
CLK
IN
=
×
fOSC(kHz)
k
COSC(pF)
=
f
C
CLK
=
100
PASSBAND
STOPBAND
GAIN
(dB)
FREQUENCY
fC
fS
fC
fS
fC
TRANSITION RATIO =
RIPPLE
VDD
VSUPPLY
IN
CLK
GND
INPUT
OUTPUT
50k
OUT
0.1
F
0.1
F
0.1
F
CLOCK
SHDN
COM
OS
MAX7408
MAX7411
MAX7412
MAX7415
Figure 2. Elliptic Filter Response
Figure 3. Offset Adjustment Circuit
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相关代理商/技术参数
参数描述
MAX7408CUA+ 功能描述:有源滤波器 5th-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
MAX7408CUA+T 功能描述:有源滤波器 5th-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
MAX7408CUA-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
MAX7408EPA 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
MAX7408EPA+ 功能描述:有源滤波器 5th-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