|
|
PDF MF8CCN Data sheet ( Hoja de datos )
| Número de pieza | MF8CCN | |
| Descripción | 4th-Order Switched Capacitor Bandpass Filter | |
| Fabricantes | National | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de MF8CCN (archivo pdf) en la parte inferior de esta página. Total 24 Páginas | ||
|
No Preview Available !
.com January 1995
MFt8aS4thhe-Oertd4eUr Switched Capacitor Bandpass FilterGeneral Description
The MF8 consists of two second-order bandpass filter
astages and an inverting operational amplifier The two filter
.Dstages are identical and may be used as two tracking sec-
ond-order bandpass filters or cascaded to form a single
w fourth-order bandpass filter The center frequency is con-
trolled by an external clock for optimal accuracy and may
w be set anywhere between 0 1 Hz and 20 kHz The ratio of
w clock frequency to center frequency is programmable to
100 1 or 50 1 Two inputs are available for TTL or CMOS
mclock signals The TTL input will accept logic levels refer-
enced to either the negative power supply pin or the ground
pin allowing operation on single or split power supplies The
oCMOS input is a Schmitt inverter which can be made to self-
oscillate using an external resistor and capacitor
.cBy using the uncommitted amplifier and resistors for nega-
tive feedback any all-pole (Butterworth Chebyshev etc )
filter can be formed This requires only three resistors for a
fourth-order bandpass filter Q of the second-order stages
Umay be programmed to any of 31 different values by the five
‘‘Q logic’’ pins The available Q values span a range from
t40 5 through 90 Overall filter bandwidth is programmed by
connecting the appropriate Q logic pins to either Va or Vb
Filters with order higher than four can be built by cascading
MF8s
Features
Y Center frequency set by external clock
Y Q set by five-bit digital word
Y Uncommitted inverting op amp
Y 4th-order all-pole filters using only three external
resistors
Y Cascadable for higher-order filters
Y Bandwidth response characteristic and center
frequency independently programmable
Y Separate TTL and CMOS clock inputs
Y 18 pin 0 3 wide package
Key Specifications
Y Center frequency range 0 1 Hz to 20 kHz
Y Q range 0 5 to 90
Y Supply voltage range 9V to 14V (g4 5V to g7V)
Y Center frequency accuracy 1% over full temperature
range
eeTypical Application Connection Diagrams
Dual-In-Line Package
ww.DataShFourth-Order Butterworth Bandpass Filter
TL H 8694– 1
Top View
TL H 8694– 2
Order Number MF8CCJ
or MF8CCN
See NS Package Number
J18A or N18A
w www.DataSheet4U.comC1995NationalSemiconductorCorporation TL H 8694
RRD-B30M115 Printed in U S A
1 page  
Typical Performance Characteristics
fCLK fo Ratio vs Clock
Frequency 50 1 Mode
fCLK fo Ratio vs Clock
Frequency 100 1 Mode
fCLK fo Ratio vs Supply
Voltage 50 1 and
100 1 Mode
fCLK fo Ratio vs
Temperature 100 1 Mode
fCLK fo Ratio vs
Temperature 50 1 Mode
Q vs Temperature
50 1 and 100 1
Q vs Supply Voltage
50 1 and 100 1
Q vs Clock Frequency
50 1 and 100 1
Q vs Clock Frequency
50 1 and 100 1
Op Amp Open Loop
Frequency Response
Positive Power
Supply Rejection
Negative Power
Supply Rejection
TL H 8694 – 24
5
5 Page 
1 0 Application Information (Continued)
fC1 and fC2 The filter’s lower and upper cutoff frequencies
These define the filter’s passband
fS1 and fS2 The boundaries of the filter’s stopband
BW The filter’s bandwidth BW e fC2 b fC1
SBW The width of the filter’s stopband SBW e fS2 b fS1
f0 The center frequency of the filter f0 is equal to the geo-
metric mean of fC1 and fC2 f0 e 0fC1fC2 f0 is also equal to
the geometric mean of fS1 and fS2
H0BP The nominal passband gain of the bandpass filter
This is normally taken to be the gain at f0
f0 BW The ratio of the center frequency to the bandwidth
For second-order filters this quantity is also known as ‘‘Q’’
SBW BW The ratio of stopband width to bandwidth This
quantity is also called ‘‘Omega’’ and may be represented by
the symbol ‘‘X’’
Amax The maximum allowable gain variation within the filter
passband This will depend on the system requirements but
typically ranges from a fraction of a dB to 3 dB
Amin The minimum allowable attenuation in the stopband
Again the required value will depend on system constraints
2) Choose a Butterworth or Chebyshev response charac-
teristic Butterworth bandpass filters are monotonic on ei-
ther side of the center frequency while Chebyshev filters
will have ‘‘ripple’’ in the passband but generally faster at-
tenuation outside the passband Chebyshev filters are spec-
ified according to the amount of ripple (in dB) within the
passband
3) Determine the filter order necessary to meet the re-
sponse requirements defined above This may be done with
the aid of the nomographs in Figures 8 and 9 for Butter-
worth and Chebyshev filters To use the nomographs draw
a line through the desired values on the AMAX AMIN scales
to the left side of the graph Draw a horizontal line to the
right of this point and mark its intersection with the vertical
line corresponding to the required ratio SBW BW The re-
quired filter order will be equal to the number of the curve
falling on or just above the intersection of the two lines This
is illustrated in Figure 10 for a Chebyshev filter with 1 dB
ripple 30 dB minimum attenuation in the stopband and
SBW BW e 3 From the Figure the required filter order is
6
4) The design tables in section 2 0 can now be used to find
the component values that will yield the desired response
for filters of order 4 through 12 The ‘‘Kn’’ give the ratios of
resistors ‘‘Rn’’ to RF and KQ is Q divided by f0 BW
As an example of the Tables’ use consider a fourth-order
Chebyshev filter with 0 5 dB ripple and f0 BW e 6 Begin by
choosing a convenient value for RF such as 100 kX From
the ‘‘0 5 dB Chebyshev’’ filter table K0 e R0 RF e 1 3405
This gives R0 e RF c 1 345 e 134 05k In a similar man-
ner R2 is found to equal 201 61k Q is found using the
column labeled KQ This gives Q e KQ c f0 BW e 8 4174
Table I shows the available Q values the nearest value is
8 5 which is programmed by tying pins 1 2 3 and 18 to Va
and pin 17 to Vb
Note that the resistor values obtained from the tables are
normalized for center frequency gain HOBP e 1 For differ-
ent gains simply divide R0 by the desired gain
5) Choose the clock-to-center-frequency ratio This will
nominally be 100 1 when pin 10 is connected to pin 12(Va)
and 50 1 when pin 10 is connected to pin 11(Vb) 100 1
generally gives a response curve nearer the ideal and fewer
(if any) problems with aliasing while 50 1 allows operation
over the highest octave of center frequencies (10 kHz to 20
kHz) Supply the MF8 with a clock signal of the appropriate
frequency to either the TTL or CMOS input depending on
the available clock logic levels
TABLE I Q and Clock-to-Center-Frequency Ratio
Versus Logic Levels on ‘‘Q-set’’ Pins
ABCDE
10000
11000
01000
10100
00100
01100
11100
01010
10010
10110
00010
11110
00110
11001
11010
11101
01001
10011
10101
01110
10001
10111
11011
11111
00101
01011
00111
00001
01101
00011
01111
50 1 mode
FCLK Fo
43 7
45 8
46 8
48 4
48 7
48 9
49 2
49 3
49 4
49 4
49 5
49 6
49 6
49 6
49 7
49 7
49 7
49 7
49 7
49 7
49 8
49 8
49 8
49 8
49 8
49 8
49 8
49 9
49 9
49 9
49 9
Q
0 45
0 71
0 96
20
25
30
40
50
57
64
76
85
10 6
11 7
12 5
13 6
14 7
15 8
16 5
17
19
22
27
30
33
40
44
57
68
79
90
100 1 mode
FCLK Fo
94 0
95 8
96 8
98 4
98 7
98 9
99 2
99 3
99 4
99 4
99 5
99 6
99 6
99 6
99 7
99 7
99 7
99 7
99 7
99 7
99 8
99 8
99 8
99 8
99 8
99 8
99 8
99 9
99 9
99 9
99 9
Q
0 47
0 73
0 98
20
25
30
40
50
57
64
76
85
10 6
11 7
12 5
13 6
14 7
15 8
16 5
17
19
22
27
30
33
40
44
57
68
79
90
11
11 Page | ||
| Páginas | Total 24 Páginas | |
| PDF Descargar | [ Datasheet MF8CCN.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| MF8CCJ | 4th-Order Switched Capacitor Bandpass Filter | National |
| MF8CCN | 4th-Order Switched Capacitor Bandpass Filter | National |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |