HM2040a VOLTAGE CONTROLLED FILTER CIRCUIT DESCRIPTION The HM2040 is a four section filter whose cutoff frequency can be exponentially controlled over a 10,000 to 1 range. This flexible building block can be used in virtually any active filter design including lowpass, highpass, bandpass and notch. Rolloff characteristics can be selected to be Butterworth, Bessel, Chevyshev or any other filter type.
FEATURES
APPLICATIONS
+/- 15V Supplies
Voltage Controlled Filters
4 Filter Sections in One Package
Parametric Equalizers
Low Noise
Music Synthesizers
Low Distortion
Music Phase Shifters
Low Control Feed-through
Tracking Filters
10,000:1 Sweep Range
Low Distortion Sine VCO’s
G = Variable Transconductance Amplifier B = High Input Impedance Buffer CTRL
IN3
1
16
V+
CAP3
2
15
CAP2
CAP
OUT
IN
G OUT3
3
14
IN2
IN4
4
13
OUT2
CAP4
5
12
CAP1
OUT4
6
11
IN1
GND
7
10
OUT1
CTRL
8
9
V-
CAP
EXPONENTIAL FUNCTION GENERATOR
B
OUT
IN
Pin Diagram
Hearn Morley Ground Floor, 7 West Mall, Clifton, Bristol
[email protected] 01179737690
G
OUT
IN
G
OUT
IN
G
B
CAP
B
CAP
Block Diagram
B
Specifications Vs=+/-15V, TA=25oC
SPECIFICATION
CONDITIONS
Functional Range Input Offset, each cell ∆Input Offset, 4 cells in series
MIN
Vcntl=0mV,-90mV Vctrl=0mV,+90mV Vctrl=0 20Hz-20kHz, Vctrl=-90mV F=1kHz, Vctrl=-90mV Vctrl=0
Transconductance Equiv. Input Noise, each cell Distortion (THD), Ein=30mVpp Tempco of Transconductance Control Sensitivity Tempco of Control Sensitivity Power Supply Current Buffer Slew Rate Buffer Output Sink Current
TYP
MAX
10,000:1 2 0.6 0.6 1/5k 0.5 0.1 +0.5 -18 3300 3 2 575
1/6k
Vctrl=0 569
5 3 3 1/4k
UNIT mV mV mV mhos uV RMS % %/oC mV/Oct ppm/oC mA V/usec
5.5 585
Absolute Maximum Ratings Any pin to VCurrent at any pin Operating Temperature Storage Temperature Power Dissipation
36V 20mA 0-70oC -40 to +100oC 1W
Applications Figures Filter Type
Figure
Gain (K)
Lowpass – Real Pole 1 -R2/R1 Highpass – Real Pole 2 1 Allpass 3 1 State Variable LP 4 -R2/R1 State Variable BP 4 R2/R1 State Variable HP 4 -R2/R1 4-Pole Lowpass 5 -(R2/R1)^4 *=R5(2R1+R2)/(R1(R4_R5)); R4||R5 = R1||(R2/2) G = Variable Transconductance Amplifier
G
200G/R2C 200G/R2C 200G/R2C 200G/R3C 200G/R3C 200G/R3C 200G/R2C
XFER char. ⁄ -K/(s+1) s/(s+1) (s-1)/(s+1) -K/(s2+ds+1) Ks/(s2+ds+1) -Ks2/(s2+ds+1) K^4/(s+1)^4
2 2 2 * * * -
B = High Input Impedance Buffer
B
G
C R1
d=1/Q
G
B
B
C1
C
R2 R 200R
Figure 1 – Lowpass Real Pole
200R
Figure 2-Highpass Real Pole
Hearn Morley Ground Floor, 7 West Mall, Clifton, Bristol
[email protected] 01179737690
R1
R2 200R
Figure 3-Allpass (Phase-shift)
x
e
51k
V/Oct. 1k
+3300ppm/C G
B
G
B
G
B
G
B 100k
1n
INPUT
(20Vpp Max)
100k
1n
R5 10k 200R
1n
R10 10k
10k
1n
R13 10k
200R
10k 200R
R16 10k
10k
2 10k
200R
1
OUTPUT
3 TL072
Resonance 20k 10k
Hearn Morley Ground Floor, 7 West Mall, Clifton, Bristol
[email protected] 01179737690
(Reverse Log.)