_CEM 3374 Dual Voltage Controlled Oscillator The CEM 3374 contains two completely independent precision voltage controlled oscillators intended for musical instruments and other sound generating applications. Each VCO features accurate linear and exponential frequency control inputs, allowing easy chromatic note generation, FM synthesis effects, and a sweepable range in excess of 50,000:1. Generating simultaneous triangle and sawtooth waveform outputs, each oscillator also includes hard sync and soft sync inputs for generating a wide variety of synchronized waveforms. The sync on oscillator A causes the triangle and sawtooth to immediately reset to zero, while the sync on oscillator B causes the waveforms to reverse direction. Variable pulse waveforms may be obtained simply by adding an inexpensive comparator. For temperature compensa- tion, the 3374 includes an on-chip temperature sensor which generates an output voltage, nominally +2.5V, proportional to chip temperature (i.e., with a TC of +3300ppm); by ensuring that the exponential control voltage is derived from this sensor output (for instance, by applying it tothe reference input of the system DAC), unsurpassed oscillator stabilities can be achieved. Requiring an absolute minimum of external components, the CEM 3374 offers high performance tone generation at rock bottom cost. Block and Connection Diagram CURTIS ELECTROMUSIC SPECIALTIES SYNC B FREQUENCY B +15V Avie (3340 TYPE) CNTL. INPUT Y +2.5V @ +3300 ppm 100pF. | w eG S3M +18V make [ot A 1000} SB SB 4 VTHB Cee] o 18|Ycc 17 16 15 14 13 REF 10| + Cc ml = | TRI TO SAW CONV. 6.8K -1 SVE ec WwW 3 = 5K = a R. MIRROR] = a V+ = TRI TO SAW CONV. "4 7 t -5V 47K 04 1000pF|_ . pF "sop I SYNC A I - FREQUENCY A (STANDARD) CNTL. INPUT Features Two Independent VCOs in a Single DIP Low Cost Per VCO Few External Parts Wide Sweep Range High Temperature Stability Accurate Linear and Expo- nential Control Glitchless Triangle and Sawtooth Waveforms from Buffered Outputs m Three Types of Sync m= Linear FM Synthesis Non Lock-up of Oscillator Waveform Phases, Even at Identical FrequenciesCEM 3374 Electrical Characteristics Voc = +15V Veg = 5V Cy = 1000pF Ta = 20C CONNECTION OF 3374 INTO TYPICAL SYSTEM Curtis Electromusic Specialties (CES) assumes no reponsibility for use of any circuitry described are implied. CES reserves the right, at any time without notice, to change said circuitry. Printed U.S.A. 1984 Parameter Minimum Typical Maximum Units Frequency Control Range 50K:1 500k:1 _ Exponential Scale Factor +17.0 +17.9 +19.0 mV/octave Exponential Scale Error! _ 0.05 0.20 % High Frequency Scale Error2 Untrimmed _ 3 7 % Trimmed _ 0.10 0.30 % Sensor Output Voitage 2.2 2.5 2.8 Vv VCO Stability? VFREQ = OmV _ +50 +100 ppm VFREQ = 90mV _ + 150 +500 ppm Unit to Unit Variation in Initial Frequency, VFREQ = 0 _ 0.2 +0.4 octave Maximum VCO Frequency _ _ 500 KHz Maximum Capacitor Charge/Discharge Current 350 450 550 vA Linear Input Offset Voltage 0 +7 +15 mV TC of Linear Offset Voitage _ 40 80 pvc Linear Input Bias Current -50 - 100 250 nA TC of Linear Input Bias Current - 2000 -500 +1000 ppm Exponential Input Bias Current4 -0.3 - 0.7 -1.3 > BA Triangle Buffer Input Current _ +0.3 +3 nA Triangle Waveform Lower Level -10 0 +10 mV Triangle Waveform Upper Level +4.85 +5.0 +5.15 Vv Triangle Waveform Symmetry 45 50 55 % Sawtooth Waveform Lower Level | -25 0 +25 mV Sawtooth Waveform Upper Level +9.4 +10.0 +10.6 Vv Buffer Output impedance Triangle _ 25 40 ohm Sawtooth _ 100 150 ohm Buffer Sink Capability Triangle 8 1.0 1.3 mA Sawtooth 0.3 0.4 0.5 mA Frequency Sensitivity to Load Change Triangle _ 3.0 5.0 %K ohm Sawtooth NONE Frequency Difference Between Oscillators for Lock-up _ .002 .006 % Sync A Input Impedance 25 50 100 Kohm Sync A Threshold 8,7 -1.0 _ 1.4 Vv Sync B Input Impedance 5.4 6.8 8.5 Kohm Sync B Threshold 8:9 +0.1 ~ +0.3 Vv Sync B Reference Voltage -1.3 1.5 -1.7 Vv Positive Supply Voltage +10 _ +16 v Negative Supply Voltage -4.5 _ -7.0 Vv Positive Supply Current +7.5 +9.5 +12.0 mA Negative Supply Current -6.5 8.0 -10.0 mA ; 1m wo g | oa > mammmmmoc Fe & _| | REFERENCE 5 [_ 3 cEM 3374 Fe oe SYSTEM a& 1 7 5 g3 DAC $3 Pe esr 7] DAC 23 5.9K aa OUTPUT I ; 1002 005 Notes Note 1. 5Hz to 1KHz Note 2. Droop at 10KHz (ICHARGE/ DISCHARGE = 100pA). Trimming is accomplished with 500 ohm to 3K ohm resistor and 10nF capacitor parallel network in series with timing capacitor. Note 3. Exponential control voltage, VEREQ; derived from termperature sensor output. VEREQ = 90mV represents 10 octave range. Note 4. At 10KHz (ICHARGE/ DISCHARGE = 100A). At other frequencies, current is scaled proportionally. Note 5. Minimum recommended load is 5K to ground. Note 6. With respect to Voc Note 7. Maximum input should be limited ; to 5V Peak or at least 10K resistor put - in series with this input to limit current. Note 8. With respect to Sync B reference voltage (Nominal voltage at pin 16). Note 9. Maximum input should be limited to +2V Peak. . so. oo oo a oo oo. ) CEM3374 1 6 1000pF 470 2 HI-FREQUENCY SCALE TRIM PULSE WIDTH oa s 47pF 100K \ 4.7K >< co earn ooo = 14 n M3374 2 ce = 1 5 z ec uw PULSE WAVEFORM GENERATION Qe . No circuit licenses