GENERAL DESCRIPTION The is a precision waveform generator IC capable of producing sine, square, triangular, sawtooth, and pulse waveforms, with a minimum number of external components and adjustments. The 8038A allows the elimination of the external distortion adjusting resistor which greatly improves the temperature drift of distortion, as well as lowering external parts count. Its operating frequency can be selected over eight decades of frequency, from 200KHz, by the choice of external R-C components. The frequency of oscillation is highly stable over a wide range of temperature and supply voltage changes. Both full frequency sweeping as well as smaller frequency variations (FM) can be accomplished with an external control voltage. Each of the three basic waveform outputs, (i.e., sine, triangle and square) are simultaneously available from independent output terminals. The XR-8038A monolithic waveform generator uses advanced processing technology and Schottky-barrier diodes to enhance its frequency performance. It can be readily interfaced with a monolithic phase-detector circuit, such as the XR-2228 to form stable phase-locked circuits. FEATURES Low Frequency Drift 50ppm/°C, Typical Simultaneous Sine, Triangle, and Square Wave Outputs Low Sine Wave Distortion THD 1% High FM and Triangle Linearity Wide Frequency Range to 200KHz Variable Duty Cycle to 98% Low Distortion Variation with Temperature APPLICATIONS Precision Waveform Generation Sweep and FM Generation Tone Generation Instrumentation and Test Equipment Design Precision PLL Design ABSOLUTE MAXIMUM RATINGS Power Supply 36V Power Dissipation (package limitation) Ceramic Package 750mW Derate Above +25°C 6.0mW/°C Plastic Package 625mW Derate Above +25°C 5mW/°C Storage Temperature Range to +150°C Small frequency deviation (FM) is accomplished by applying modulation voltage to Pins 7 and 8; large frequency deviation (sweeping) is accomplished by applying voltage to Pin 8 only. Sweep range is typically 1000:1. The square wave output is an open collector transistor; output amplitude swing closely approaches the supply voltage. Triangle output amplitude is typically 1/3 of the supply, and sine wave output reaches 0.22 of the supply voltage. The XR-8038A precision waveform generator produces highly stable and sweepable square, triangle, and sine waves across eight frequency decades. The is an advanced version of the XR-8038, with improved sine distortion temperature drift. The device time base employs resistors and a capacitor for frequency and duty cycle determination. The generator contains dual comparators, a flip-flop driving a switch, current sources, buffers, and a sine wave convertor. Three identical frequency outputs are simultaneously available. Supply voltage can range from to ±15V with dual supplies. Unadjusted sine wave distortion is typically less than 0.7% with the sine wave distortion adjust pin (Pin 1) open. Distortion levels may be improved by including a 100k potentiometer between the supplies, with the wiper connected to Pin 1. PIN ASSIGNMENT
ORDERING INFORMATION Part Number XR-8038ACN XR-8038ACP Package Ceramic Plastic Ceramic Plastic Operating Temperature to +70°C
ELECTRICAL CHARACTERISTICS Test Conditions: 3300pF, S1 closed, unless otherwise specified.
8038AM/8038A PARAMETERS GENERAL CHARACTERISTICS Supply Voltage, VS Single Supply Dual Supplies Supply Current V mA MIN TYP MAX MIN 8038AC TYP MAX UNITS CONDITIONS
FREQUENCY CHARACTERISTICS (Measured at Pin 9) Range of Adjustment Max. Operating Frequency Lowest Practical Frequency Max. Sweep Frequency of FM Input FM Sweep Range FM Linearity 10:1 Ratio Range of Timing Resistors Temperature Stability XR-8038A XR-8038AC Power Supply Stability OUTPUT CHARACTERISTICS Square-Wave Amplitude (Peak-to-Peak) Saturation Voltage Rise Time Fall Time Duty Cycle Adjustment Triangle/Sawtooth/Ramp Amplitude (Peak-to-Peak) Linearity Output Impedance Sine-Wave Amplitude (Peak-to-Peak) Distortion Unadjusted Adjusted THD/T x VSPLY V nsec % x VSPLY % x VSPLY % Measured at Pin = 100k Isink = 4.7k Measured at Pin = 100k IOUT = 1M (Notes = 1M (Notes ppm/°C %/V to +70°C (Note KHz Hz kHz % k ppm/°C S1 Open (Notes 3) S1 Open (Note 3) Values of RA and RA = RB, C1= 500µF (Low Leakage Capacitor)
Note 1: Currents through RA and RB not included. Note 2: VSUPPLY = 20V. Note 3: Apply sweep voltage at Pin 8. VCC (1/3 VSUPPLY 2) VPIN 8 VCC VSUPPLY = Total Supply Voltage across the IC Note VS 15V. Note 5: Pin 12 open circuited (No. 82k resistor as standard 8038). Note 6: Triangle duty cycle set at 50%, use RA and RB. Note RL is decreased distortion will increase, RL min 50k.