MF4 Datasheet, PDF (1/14 Pages) National Semiconductor (TI) – MF4 4th Order Switched Capacitor Butterworth Lowpass Filter

July 1999
MF4 4th Order Switched Capacitor Butterworth
Lowpass Filter
General Description
The MF4 is a versatile, easy to use, precision 4th order But-
terworth low-pass filter. Switched-capacitor techniques elimi-
nate external component requirements and allow a
clock-tunable cutoff frequency. The ratio of the clock fre-
quency to the low-pass cutoff frequency is internally set to 50
to 1. A Schmitt trigger clock input stage allows two clocking
options, either self-clocking (via an external resistor and ca-
pacitor) for stand-alone applications, or for tighter cutoff fre-
quency control an external TTL or CMOS logic compatible
clock can be applied. The maximally flat passband frequency
response together with a DC gain of 1 V/V allows cascading
MF4 sections together for higher order filtering.
Features
n Low Cost
n Easy to use
n 8-pin mini-DIP or 14-pin wide-body S.O.
n No external components
n 5V to 14V supply voltage
n Cutoff frequency range of 0.1 Hz to 20 kHz
n Cutoff frequency accuracy of ± 0.3% typical
n Cutoff frequency set by external clock
n Separate TTL and CMOS/Schmitt-trigger clock inputs
Connection Diagram
Dual-In-Line Package
Block Diagram
DS005064-2
Order Number MF4CN-50
See NS Package Number N08E
TRI-STATE^® is a registered trademark of National Semiconductor Corp.
© 1999 National Semiconductor Corporation DS005064
DS005064-1
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