~National
~ Semiconductor
MF5 Universal Monolithic Switched Capacitor Filter
General Description
The MF5 consists of an extremely easy to use, general pur-
pose CMOS active filter building block and an uncommitted
op amp. The filter building block, together with an external
clock and a few resistors, can produce various second order
functions. The filter building block has 3 output pins. One of
the output pins can be configured to perform highpass, all-
pass or notch functions and the remaining 2 output pins
perform bandpass and lowpass functions. The center fre-
quency of the filter can be directly dependent on the clock
frequency or it can depend on both clock frequency and
external resistor ratios. The uncommitted op amp can be
used for cascading purposes, for obtaining additional all-
pass and notch functions, or for various other applications.
Higher order filter functions can be obtained by cascading
several MF5s or by using the MF5 in conjuction with the
MF10 (dual switched capacitor filter building block). The
MF5 is functionally compatible with the MF10. Any of the
classical filter configurations (such as Butterworth, Bessel,
Cauer and Chebyshev) can be formed.
Features
II Low cost
III 14-pin DIP or 14-pin Surface Mount (SO) wide-body
package
II Easy to use
II Clock to center frequency ratio accuracy ± 0.6%
II Filter cutoff frequency stability directly dependent on
external clock quality
II Low sensitivity to external component variations
II Separate highpass (or notch or allpass), bandpass, low-
pass outputs
II foXQ range up to 200 kHz
III Operation up to 30 kHz (typical)
III Additional uncommitted op-amp
Block and Connection Diagrams
v- 81
BP lP
14
INVI
AGND
elK
50/100
l8hn----I
~2
INV2
-A2
13
V
AGNO D2
TLIH/S066-1
All Packages
BP
N/AP/HP
INV1
S1
V+
l Sh 7
14 lP
13 V02
INV2
AGND
V-
50/100
Order Number MF5CN
See NS Package Number N14A
Order Number MF5CWM
See NS Package Number M14B
8 elK
Top View
TLIH/S066-2
1-119
