CURTIS ELECTROMUSIC SPECIALTIES ~ CEM 3312 MS ae ee Voltage Controlled Envelope Generator The CEM 3312 is a self-con- tained, precision ADSR type envelope generator intended for musical instruments and other sound generation applications. A unique feature of this device is an additonal control input, called Peak, which allows the overall amplitude of the envelope waveform to be varied without affecting any of the time constants. Thus, amount of envelope can be precisely controlled and without the need for an extra VCA. The Peak control input may be varied from 0 to +6.5 volts, causing the envelope amplitude to vary from 0 to +5 volts. Attack, decay, and release times are exponentially voitage controllable over a wide range, and the sustain level is linearly voltage controllable from 0 to 100% of the peak voltage. The novel design approach pioneered by Curtis still provides the best control voltage rejection in the industry. In addition, much care has been given in the design to allow superior tracking and repeatability of all parameters from unit to unit without trimming (such as using an external resistor for Rx instead of the wide tolerance monolithic resistor used in competing units). Finally, the control voltage required for.all five inputs ranges from zero to positive, allowing easy interface to the system Sample & Holds. Precise, flexible, and low in cost, the CEM 3312 is the ideal choice for dynamic polyphonic envelope generation. Features m New Parameter, called Peak, for Controlling the Amplitude of the ADSR Waveform = Eliminates Envelope Amount VCA # True RC Envelope Shape # All Control Inputs Range Zero to a Positive Voltage for Easy Interface to Sample & Holds. # Exceptionally Low Control Voltage Feedthrough. Accurate Exponential Time Control Scales = Good Repeatability and Tracking Between Units Without External Trim m Independent Gate and Trigger Circuit Block and Connection Diagram ATTACK RELEASE DECAY PEAK 10K 40K [> 470.2) 470 2) 470 16 15 14 13 ENVELOPE OUTPUT A, D,S, &R CONTROL VOLTAGES RANGE FROM 0 To +5V PEAK CONTROL VOLTAGE RANGES FROM 0 TO +6.5V TO VARY OUTPUT FROM 0 TO +5V GATE =CEM 3312 Electrical Characteristics Voc = +15.0V) Veg = -15.0V) Rx = 24K Tay = 20C Parameter Minimum Typical Maximum Units Time Control Range 50,000:1 250,000:1 _ _ Attack Asymptote Voitage (V7) 1 6.1 6.5 6.9 Vv Attack Peak Voltage(Vp) | 4.7 5.0 5.3 Vv PeakC.V. Range 0 6.5 Vv Envelope Amplitude to Peak C.V. Ratio .735 765 .795 Peak C.V. Input Impedance 3.2 4.3 5.4 Kohm Sustain C.v. Range? 0 _ +5.0 Vv Time Constants C.V. Range? 0 _ +240 mV Control Scaie Factor +58.5 +60 +61.5 mV/Decade| Temperature Coefficient of Control Scale + 3,000 +3,300 +3,600 ppm ATK,DCY,RLS Scate Tracking 300 0 +300 pV/Decade Exponential Full Scale Control Accuracy 4 50nA < Ig < 50puA _ 0.3 1.5 % 2nA <Ig <200HA 2 10 % Attack C.V. Feedthrough 5 6 90 pV Decay C.V. Feedthrough? NONE Release C.V. Feedthrough 5 NONE Attack Asymptote Error (Vo Vop) -3 +10 +23 mv Sustain Final Voltage Error (Vo Ves) -3 +10 +23 mV Release Final Voltage Error (yo) -3 +10 +23 mV RC Curve Asymptote Error 6 VCA,D,R =9 _ -6, 60 uv VCA,D,R = +240mVv _ -125 1250 mv Input Current (Ijjy) to Output Current (IQ) Ratio, Vca.D,R =0 Charge Current (ATK) 75. 1 1.3 Discharge Current (DCY,RLS) 83 1 1.2 Buffer Input Current (Igo) _ -0.5 -5 nA Op Amp Input Current (lp) -150 - 400 800 nA Gate Threshoid 2.0 2.3 2.6 Vv Gate Input Current +5 +25 +100 uA Trigger Pulse Required to Trigger Envelope +1.1 +1.3 +1.5 Vv Trigger Input Impedance 2.4 3 4 Kohm Time Control Input Current -0.5 _ 2500 . nA Sustain Control Input Current 150 400 - 800 nA Output Current Sink Capability - 420 560 - 700 HA Buffer Output Impedance 100 200 350 ohm Positive Supply Voltage Range +10.5 _ +18 v Negative Supply Voltage Range 8 4.5 -18 Vv Supply Current 5.6 7.5 9.4 mA Input and Output Waveforms 5.0V PEAK = 6.5V SUSTAIN = 2.5V PEAK = 6.5V SUSTAIN = 2.5V PEAK = 4.0V SUSTAIN = 1.5V | { 1.5V MIN. t OUTPUT TRIGGER GATE Covered by U.S. Patent #4,004,141. Curtis Electromusic Specialties (CES) assumes no responsibility 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. 1980 Notes Note 1: Peak C.V. input pin left open. Note 2: Must never be greater than Peak C.V. Note 3: Nominal for 10,000:1 time constant range. Can be larger. See Hints. Note 4: Scale factor determined at mid-range. Spec represents total deviation from ideal at range extremities. Note 5: Output is at either sustain final voltage or release final voltage. VCA:DR varies 0 to +240mvV. Note 6: Spec represents the difference between the actual final voltages (attack asymptote voltage, sustain final voltage, and release final voltage in the case of attack, decay, and release respectively) and the apparent voltage to which the output seems to be approaching asymptotically. Note 7: Spec also represents time constant variation between units for VCA-D-R = 9. Note 8: Current limiting resistor required when Vee > 6.0 volts. l {Px Tz J 16 Output 15 13 12 "1 10 t acooahd aon AO fw Nh VQQOO0000 RX Figure 1: Connection to External Buffer