XR-8038A May 1994-4 Precision Waveform Generator GENERAL DESCRIPTION The XR-8038A 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 0.001Hz to 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. PIN ASSIGNMENT 1 14 NC 2 13 NC 3 12 SINE ADJ 4 11 –V OR GND 5 10 TIMING CAPACITOR +VCC 6 9 FM BIAS 7 8 SINE ADJ ~ DUTY CYCLE ADJ XR-8038A FM SWEEP INPUT ORDERING INFORMATION Part Number XR-8038AM XR-8038AN XR-8038AP XR-8038ACN XR-8038ACP Package Ceramic Ceramic Plastic Ceramic Plastic Operating Temperature –55°C to +125°C 0°C to +70°C 0°C to +70°C 0°C to +70°C 0°C to +70°C SYSTEM DESCRIPTION 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 0.001Hz to 200KHz Variable Duty Cycle 2% 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 The XR-8038A precision waveform generator produces highly stable and sweepable square, triangle, and sine waves across eight frequency decades. The XR-8038A 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 10V to 30V, or ±5V 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 100kΩ potentiometer between the supplies, with the wiper connected to Pin 1. 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 –65°C 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. XR-8038A ELECTRICAL CHARACTERISTICS Test Conditions: VS = ±5V to ±15V, TA = 25°C, RL = 1MΩ, RA = RB = 10kΩ, C1 = 3300pF, S1 closed, unless otherwise specified. 8038AM/8038A PARAMETERS MIN 8038AC TYP MAX MIN 10 ±5 12 30 ±15 15 TYP MAX UNITS 12 30 ±15 20 V V mA CONDITIONS GENERAL CHARACTERISTICS Supply Voltage, VS Single Supply Dual Supplies Supply Current 10 ±5 VS = ±10V (Note 1) FREQUENCY CHARACTERISTICS (Measured at Pin 9) Range of Adjustment Max. Operating Frequency 200 Lowest Practical Frequency Max. Sweep Frequency of FM Input FM Sweep Range FM Linearity 10:1 Ratio Range of Timing Resistors Temperature Stability XR-8038AM XR-8038A XR-8038AC Power Supply Stability 200 KHz 0.001 0.001 Hz 100 1000:1 0.1 100 1000:1 0.2 kHz 0.5 1000 50 50 1000 % kΩ S1 Open (Notes 2 & 3) S1 Open (Note 3) Values of RA and RB — ppm/°C TA = –55°C to +125°C 50 0.05 ppm/°C %/V TA = 0°C to +70°C (Note 4) 0.98 0.2 100 40 x VSPLY V nsec nsec % 0.5 — RA = RB, = 1.5kΩ, C1 = 680pF RL = 10K RA = RB = 1MΩ, C1= 500µF (Low Leakage Capacitor) — 100 0.05 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 0.9 0.98 0.2 100 40 2 0.3 0.2 0.9 0.4 98 0.33 0.05 200 0.22 0.7 0.5 0.5 2 0.3 0.2 1.5 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 4: 10V ≤ VS ≤ 30V or ±5V ≤ VS ≤ 15V. Note 5: Pin 12 open circuited (No. 82kΩ resistor as standard 8038). Note 6: Triangle duty cycle set at 50%, use RA and RB. Note 7: As RL is decreased distortion will increase, RL min ≈ 50kΩ. 2 0.5 98 0.33 0.1 200 0.22 0.8 0.5 0.3 3 x VSPLY % Ω x VSPLY % % % Measured at Pin 9 RL = 100kΩ Isink = 2mA RL = 4.7kΩ RL = 4.7kΩ Measured at Pin 3. RL = 100kΩ IOUT = 5mA RL = 100kΩ RL = 1MΩ (Notes 5, 6 & 7) RL = 1MΩ (Notes 5, 6 & 7) XR-8038A Notes 3 XR-8038A NOTICE EXAR Corporation reserves the right to make changes to the products contained in this publication in order to improve design, performance or reliability. EXAR Corporation assumes no responsibility for the use of any circuits described herein, conveys no license under any patent or other right, and makes no representation that the circuits are free of patent infringement. Charts and schedules contained herein are only for illustration purposes and may vary depending upon a user's specific application. While the information in this publication has been carefully checked; no responsibility, however, is assumed for inaccuracies. EXAR Corporation does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless EXAR Corporation receives, in writing, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized; (b) the user assumes all such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances. Copyright 1986 EXAR Corporation Data Sheet June 1994 Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited. 4