~ CEM 3350 CURTIS ELECTROMUSIC SPECIALTIES Dual Voltage Controlled State Variable Filter The CEM 3350 is a dual voltaged controlled state-variable filter intended for electronic musical instruments and other signal processing applications. Each filter provides both voltage control of center/cut-off frequency over more than 12 octaves and voltage control of Q from 1/2 to greater than 40. All control scales are exponential, allowing for easier control of the parameters over their wide range. Although the two filters are completely independent, they may be easily interconnected to form a wide variety of filter responses. Each filter also provides two signal inputs: For signals applied to the fixed gain input, the output will remain constant as the Q is varied, while for signals applied to the variable gain input, the output decreases as Q is increased. The input signai may be proportioned between these two inputs to provide any desired characteristic. Finally, each filter provides two simultaneous outputs, making directly available low-pass and band-pass, or band-pass and high-pass responses depending upon where the input signal is applied. Able to operate over a wide supply range, the versatile CEM 3350 allows new and unique filter responses to be created with a high degree of voltage control over the defining parameters. Block and Connections Diagram VCF #2 HIGH PASS VCE #2 OUTPUT SIGNAL IN RESONANCE CNTL. INPUT FREQUENCY CNTL. INPUT 2 8 20022 J] i Ir gb] t Cip Vip ve] | Vor GND to +12V Vec| Yep} Viv 16 47K $ All OP AMPS ARE LOW NOISE BI-FET TYPES 22K VCF #1 - LOWPASS VCF #1 OUTPUT SIGNAL INPUT dl as Cp Qo a 10K RESONANCE FREQUENCY CNTL.INPUT CNTL. INPUT VCF #2 BANDPASS OUTPUT VCF #1 BANDPASS OUTPUT Features: m Low Cost # Two Independent State Variable Filters in a Single 16 Pin DIP Separate Frequency and Q Control Inputs for Each @ Wide Frequency Sweep and Q Control Range m Exponential Control Scales for Both Frequency and Q Two Simultaneous Outputs on Each: Low-Pass and Band-Pass or Band-Pass and High-Pass Possible # Two Simultaneous Inputs for Each: Fixed Gain and Variable Gain m Chip Configurable Into Many Unique V.C. Filters m Wide Supply Range: +3V to +16V CEM 3350 Electrical Characteristics Notes Note 1. Nominal for 1000:1 Sweep Veco = +12V) Veg = -12V Ine = 400UA Ta = 20C Note 2. With Q Enhancement _ ; . - Note 3. +60mV < Vor < +260mV. Most Parameter Minimum = Typical = Maximum Units of this error occurs at higher transconduc- Frequency Control Range 12 13.5 octaves tance portion of scale. Frequency C.V. Input Range! +60 _ +260 mV aopears st Von or Vee pin 260mV. As Frequency Control Scale Factor, Midrange -~18.5 -19.6 20.6 mV/octave Note 5. 150mV<Voq <+40mvV. As Q Control Range? 0.05 _ oscillation appears at Vcp or Vpp pin. Q C.V. Input Range +40 - 150 mV Note 6. Vig or Viy = 40 mvV.P.P. Q Control Scale Factor, Midrange -62 65 -68 mvV/10x Note 7. Vcr = 0. As appears at Vcp or Maximum Q Without Enhancement 30 50 _ Vep pin. 20KHz bandwidth. Note 8. Varies proportionally with Tempco of Frequency and Q Control Scales | +3000 +3300 +3600 ppm transconductance. Exponential Error of Frequency Note 9. Varies inversely with and Q Control Scales3 3.0 10 % transconductance. Note 10. Total supply voltage across the Transconductance of Frequency : Transconductors, Vcr = 0 4900 6900 9700 mho chip should not exceed 26V. Transconductance of Q 1/2 CEM 3350 Transconductor, VCF .Q = 9 3200 4900 7400 mho Maximum Transconductance of Frequency and Q Ttransconductors 11,000 14,200 18,500 umho Tempco of Transconductance atVcf.qg=0] 3000 3300 3600 ppm Frequency Control Feedthrough4 = 1.0 4.0 mV Q Control Feedthrough5 1.0 3.0 mv Output DC Offset, midrange _ 1.0 +5.0 mV Distortion in Passband _ 1.0 5.0 % : Output Noise _ 0.8 2.5 uV.R.M.S. Signal Input Bias Current, Vor,q = 08 0.6 1.4 2.8 BA Frequency and Q Control Input Bias Current 0.7 1.6 3.2 HA Transconductor Output Impedance? 1 + BANDPASS Vor,q =0 1.0 4.0 Mohm - ~ ouTPUT . Voltage at Pin 1 Referred to Veg 1.2 1.4 1.6 Vv USING BANDPASS OUTPUT Reference Current Range 10 _ 600 vA Positive Supply Current, Vcr,.q =0 _ 2.5 3.0 mA Negative Supply Current _ 6.5 7.5 mA Supply Voltage Range 19 +3 +16 Vv 1/2 CEM 3350 1/2 CEM 3350 ViF )- LOWPASS OUTPUT Ce FILTER INPUT y 2002 2 = . B.P. OUTPUT . FIGURE 6: Hi @ OVERLOAD LIMITER FIGURE 9: Q ENHANCEMENT USING LOWPASS OUTPUT o, CURTIS ELECTROMUSIC SPECIALTIES Curtis Electromusic Specialties (CES) assumes no reponsibility for use of any circuitry described. No circuit licenses are implied. CES reserves the right, at any time without notice, to change said circuitry. Printed U.S.A. 1984 Wo