XR-2206 Monolithic Function Generator

Transcription

1 ...the analog plus company TM XR-0 Monolithic Function Generator FEATURES Low-Sine Wave Distortion, 0.%, Typical Excellent Temperature Stability, 0ppm/ C, Typ. Wide Sweep Range, 000:, Typical Low-Supply Sensitivity, 0.0%V, Typ. Linear Amplitude Modulation TTL Compatible FSK Controls Wide Supply Range, 0V to V Adjustable Duty Cycle, % TO % APPLICATIONS Waveform Generation Sweep Generation AM/FM Generation V/F Conversion FSK Generation Phase-Locked Loops (VCO) June -3 GENERAL DESCRIPTION The XR-0 is a monolithic function generator integrated circuit capable of producing high quality sine, square, triangle, ramp, and pulse waveforms of high-stability and accuracy. The output waveforms can be both amplitude and frequency modulated by an external voltage. Frequency of operation can be selected externally over a range of 0.0Hz to more than MHz. The circuit is ideally suited for communications, instrumentation, and function generator applications requiring sinusoidal tone, AM, FM, or FSK generation. It has a typical drift specification of 0ppm/ C. The oscillator frequency can be linearly swept over a 000: frequency range with an external control voltage, while maintaining low distortion. ORDERING INFORMATION Operating Part No. Package Temperature Range XR-0M Lead 300 Mil CDIP - C to C XR-0P Lead 300 Mil PDIP 0 C to C XR-0CP Lead 300 Mil PDIP 0 C to 0 C XR-0D Lead 300 Mil JEDEC SOIC 0 C to 0 C Rev..03 EXAR Corporation, 0 Kato Road, Fremont, CA 3 (0) -000 (0) -0

2 Timing Capacitor TC TC VCO GND BIAS 0 SYNCO Timing Resistors TR TR Current Switches Multiplier And Sine Shaper STO FSKI AMSI 3 MO WAVEA 3 WAVEA SYMA SYMA Figure. XR-0 Block Diagram Rev..03

3 AMSI STO MO TC TC TR TR SYMA SYMA WAVEA WAVEA GND SYNCO BIAS FSKI AMSI STO MO TC TC TR TR SYMA SYMA WAVEA WAVEA GND SYNCO BIAS FSKI Lead PDIP, CDIP (0.300 ) Lead SOIC (Jedec, ) PIN DESCRIPTION Pin # Symbol Type Description AMSI I Amplitude Modulating Signal Input. STO O Sine or Triangle Wave Output. 3 MO O Multiplier Output. Positive Power Supply. TC I Timing Capacitor Input. TC I Timing Capacitor Input. TR O Timing Resistor Output. TR O Timing Resistor Output. FSKI I Frequency Shift Keying Input. 0 BIAS O Internal Voltage Reference. SYNCO O Sync Output. This output is a open collector and needs a pull up resistor to. GND Ground pin. 3 WAVEA I Wave Form Adjust Input. WAVEA I Wave Form Adjust Input. SYMA I Wave Symetry Adjust. SYMA I Wave Symetry Adjust. Rev..03 3

4 DC ELECTRICAL CHARACTERISTICS Test Conditions: Test Circuit of Figure Vcc = V, T A = C, C = 0.0 F, R = 00k, R = 0k, R 3 = k Unless Otherwise Specified. S open for triangle, closed for sine wave. XR-0M/P XR-0CP/D Parameters Min. Typ. Max. Min. Typ. Max. Units Conditions General Characteristics Single Supply Voltage 0 0 V Split-Supply Voltage 3 3 V Supply Current 0 ma R 0k Oscillator Section Max. Operating Frequency MHz C = 000pF, R = k Lowest Practical Frequency Hz C = 0 F, R = M Frequency Accuracy % of f o f o = /R C Temperature Stability Frequency ppm/ C 0 C T A 0 C R = R = 0k Sine Wave Amplitude Stability ppm/ C Supply Sensitivity %/V V LOW = 0V, V HIGH = 0V, R = R = 0k Sweep Range 000: 000: 000: f H = f L f R = k f R = M Sweep Linearity 0: Sweep % f L = khz, f H = 0kHz 000: Sweep % f L = 00Hz, f H = 00kHz FM Distortion % 0% Deviation Recommended Timing Components Timing Capacitor: C F Figure Timing Resistors: R & R k Triangle Sine Wave Output Figure 3 Triangle Amplitude 0 0 mv/k Figure, S Open Sine Wave Amplitude mv/k Figure, S Closed Max. Output Swing Vp-p Output Impedance Triangle Linearity % Amplitude Stability db For 000: Sweep Sine Wave Distortion Without Adjustment.. % R = 30k With Adjustment % See Figure and Figure Notes Output amplitude is directly proportional to the resistance, R 3, on Pin 3. See Figure 3. For maximum amplitude stability, R 3 should be a positive temperature coefficient resistor. Bold face parameters are covered by production test and guaranteed over operating temperature range. Rev..03

5 DC ELECTRICAL CHARACTERISTICS (CONT D) XR-0M/P XR-0CP/D Parameters Min. Typ. Max. Min. Typ. Max. Units Conditions Amplitude Modulation Input Impedance k Modulation Range % Carrier Suppression db Linearity % For % modulation Square-Wave Output Amplitude Vp-p Measured at Pin. Rise Time 0 0 ns C L = 0pF Fall Time 0 0 ns C L = 0pF Saturation Voltage V I L = ma Leakage Current A = V FSK Keying Level (Pin ) V See section on circuit controls Reference Bypass Voltage V Measured at Pin 0. Notes Output amplitude is directly proportional to the resistance, R 3, on Pin 3. See Figure 3. For maximum amplitude stability, R 3 should be a positive temperature coefficient resistor. Bold face parameters are covered by production test and guaranteed over operating temperature range. Specifications are subject to change without notice ABSOLUTE MAXIMUM RATINGS Power Supply V Power Dissipation mW Derate Above C mw/ C Total Timing Current ma Storage Temperature C to 0 C SYSTEM DESCRIPTION The XR-0 is comprised of four functional blocks; a voltage-controlled oscillator (VCO), an analog multiplier and sine-shaper; a unity gain buffer amplifier; and a set of current switches. The VCO produces an output frequency proportional to an input current, which is set by a resistor from the timing terminals to ground. With two timing pins, two discrete output frequencies can be independently produced for FSK generation applications by using the FSK input control pin. This input controls the current switches which select one of the timing resistor currents, and routes it to the VCO. Rev..03

6 F FSK Input R R C VCO Current Switches Mult. And Sine Shaper Symmetry Adjust K XR-0 R3 0K K F F S THD Adjust 00 S = Open For Triangle = Closed For Sinewave Triangle Or Sine Wave Output Square Wave Output.K.K Figure. Basic Test Circuit Peak Output Voltage (Volts) 3 Triangle Sinewave R 3 in (K Figure 3. Output Amplitude as a Function of the Resistor, R3, at Pin 3 I CC (ma) 0 K 0K 30K K 0 C Max. Package Dissipation 0 (V) Figure. Supply Current vs Supply Voltage, Timing, R Rev..03

7 Timing Resistor ( ) 0M M 00K 0K MAXIMUM ÁÁÁÁÁÁ TIMING R ÁÁÁÁÁÁ ÁÁÁÁÁ NORMAL ÁÁÁÁÁ RANGE MINIMUM ÁÁÁÁÁ TIMING R ÁÁÁÁÁ TYPICAL ÁÁÁÁÁ VALUE ÁÁÁÁÁ K Frequency (Hz) 0 0 Normal Output Amplitude V V / DC Voltage At Pin Figure. R versus Oscillation Frequency. Figure. Normalized Output Amplitude versus DC Bias at AM Input (Pin ) Distortion (%) ÁÁÁÁÁÁÁ C = 0.0 F ÁÁÁÁÁÁÁ Trimmed For Minimum Distortion At 30 K 3 ÁÁÁÁÁÁÁ Timing R K( Distortion (%) 3 0 R=3K ÁÁÁ ÁÁÁÁ R L =0K ÁÁÁÁ V OUT =0.VRMS Pin 0 00 K 0K 00K M Frequency (Hz) Figure. Trimmed Distortion versus Timing Resistor. Figure. Sine Wave Distortion versus Operating Frequency with Timing Capacitors Varied. Rev..03

8 3 R=M C=0.0 F Frequency Drift (%) R=00K R=0K R=K R=K R=K R=0K R=00K R=K R=M ÁÁ Rc Sweep Input - V C I C R I T Pin or I B 3V - Ambient Temperature (C ) Figure. Frequency Drift versus Temperature. Figure 0. Circuit Connection for Frequency Sweep. F C VCO Mult. And Sine Shaper 3 S S Closed For Sinewave 00 M R R K Current Switches 0 3 XR-0 R 3 0K 0K F 0 F Triangle Or Sine Wave Output Square Wave Output.K.K Figure. Circuit tor Sine Wave Generation without External Adjustment. (See Figure 3 for Choice of R 3 ) Rev..03

9 F F = M RC R R K C VCO Current Switches 0 F Mult. And Sine Shaper 3 R 3 0K Symmetry Adjust K R B S Closed For Sinewave 3 S R A 00 Triangle Or Sine Wave Output Square Wave Output XR-0 0 F 0K.K.K Figure. Circuit for Sine Wave Generation with Minimum Harmonic Distortion. (R 3 Determines Output Swing - See Figure 3) F >V F <V F FSK Input R R C VCO Current Switches Mult. And Sine Shaper 3 00 FSK Output F=/RC F=/RC 0 3 R 3 XR-0 0K F 0 F.K.K Figure 3. Sinusoidal FSK Generator Rev..03

10 R R C VCO Current Switches F Mult. And Sine Shaper 3 Duty Cycle = f C R R R R R Sawtooth Output Pulse Output 0 3 XR-0 R 3 K F 0 F.K.K.K Figure. Circuit for Pulse and Ramp Generation. Frequency-Shift Keying The XR-0 can be operated with two separate timing resistors, R and R, connected to the timing Pin and, respectively, as shown in Figure 3. Depending on the polarity of the logic signal at Pin, either one or the other of these timing resistors is activated. If Pin is open-circuited or connected to a bias voltage V, only R is activated. Similarly, if the voltage level at Pin is V, only R is activated. Thus, the output frequency can be keyed between two levels. f and f, as: f = /R C and f = /R C For split-supply operation, the keying voltage at Pin is referenced to V -. Output DC Level Control APPLICATIONS INFORMATION Sine Wave Generation Without External Adjustment Figure shows the circuit connection for generating a sinusoidal output from the XR-0. The potentiometer, R at Pin, provides the desired frequency tuning. The maximum output swing is greater than V /, and the typical distortion (THD) is <.%. If lower sine wave distortion is desired, additional adjustments can be provided as described in the following section. The circuit of Figure can be converted to split-supply operation, simply by replacing all ground connections with V -. For split-supply operation, R 3 can be directly connected to ground. The dc level at the output (Pin ) is approximately the same as the dc bias at Pin 3. In Figure, Figure and Figure 3, Pin 3 is biased midway between V and ground, to give an output dc level of V /. Rev..03 0

11 With External Adjustment: The harmonic content of sinusoidal output can be reduced to -0.% by additional adjustments as shown in Figure. The potentiometer, R A, adjusts the sine-shaping resistor, and R B provides the fine adjustment for the waveform symmetry. The adjustment procedure is as follows:. Set R B at midpoint and adjust R A for minimum distortion.. With R A set as above, adjust R B to further reduce distortion. Triangle Wave Generation The circuits of Figure and Figure can be converted to triangle wave generation, by simply open-circuiting Pin 3 and (i.e., S open). Amplitude of the triangle is approximately twice the sine wave output. PRINCIPLES OF OPERATION Description of Controls Frequency of Operation: The frequency of oscillation, f o, is determined by the external timing capacitor, C, across Pin and, and by the timing resistor, R, connected to either Pin or. The frequency is given as: f 0 RC Hz and can be adjusted by varying either R or C. The recommended values of R, for a given frequency range, as shown in Figure. Temperature stability is optimum for k < R < 00k. Recommended values of C are from 000pF to 00 F. Frequency Sweep and Modulation: Frequency of oscillation is proportional to the total timing current, I T, drawn from Pin or : FSK Generation f 30I T (ma) Hz C( F) Figure 3 shows the circuit connection for sinusoidal FSK signal operation. Mark and space frequencies can be independently adjusted by the choice of timing resistors, R and R ; the output is phase-continuous during transitions. The keying signal is applied to Pin. The circuit can be converted to split-supply operation by simply replacing ground with V -. Timing terminals (Pin or ) are low-impedance points, and are internally biased at 3V, with respect to Pin. Frequency varies linearly with IT, over a wide range of current values, from A to 3mA. The frequency can be controlled by applying a control voltage, V C, to the activated timing pin as shown in Figure 0. The frequency of oscillation is related to VC as: Pulse and Ramp Generation f RC R R C V C 3 Hz Figure shows the circuit for pulse and ramp waveform generation. In this mode of operation, the FSK keying terminal (Pin ) is shorted to the square-wave output (Pin ), and the circuit automatically frequency-shift keys itself between two separate frequencies during the positive-going and negative-going output waveforms. The pulse width and duty cycle can be adjusted from % to % by the choice of R and R. The values of R and R should be in the range of k to M. where V C is in volts. The voltage-to-frequency conversion gain, K, is given as: K f V C 0.3 R C C Hz V CAUTION: For safety operation of the circuit, I T should be limited to 3mA. Rev..03

12 Output Amplitude: Maximum output amplitude is inversely proportional to the external resistor, R 3, connected to Pin 3 (see Figure 3). For sine wave output, amplitude is approximately 0mV peak per k of R 3 ; for triangle, the peak amplitude is approximately 0mV peak per k of R 3. Thus, for example, R 3 = 0k would produce approximately 3V sinusoidal output amplitude. Amplitude Modulation: Output amplitude can be modulated by applying a dc bias and a modulating signal to Pin. The internal impedance at Pin is approximately 00k. Output amplitude varies linearly with the applied voltage at Pin, for values of dc bias at this pin, within volts of / as shown in Figure. As this bias level approaches /, the phase of the output signal is reversed, and the amplitude goes through zero. This property is suitable for phase-shift keying and suppressed-carrier AM generation. Total dynamic range of amplitude modulation is approximately db. CAUTION: AM control must be used in conjunction with a well-regulated supply, since the output amplitude now becomes a function of. VR V VR V VR Int ni. Reg. VR V V Figure. Equivalent Schematic Diagram Rev..03

13 LEAD CERAMIC DUAL-IN-LINE (300 MIL CDIP) Rev..00 D E E Base Plane A A Seating Plane L B e B α c INCHES MILLIMETERS SYMBOL MIN MAX MIN MAX A A B B c D E E BSC. BSC e 0.00 BSC. BSC L α 0 0 Note: The control dimension is the inch column Rev..03 3

14 LEAD PLASTIC DUAL-IN-LINE (300 MIL PDIP) Rev..00 E D E Seating Plane A L B e B A A α e A e B C INCHES MILLIMETERS SYMBOL MIN MAX MIN MAX A A A B B C D E E e 0.00 BSC. BSC e A BSC. BSC e B L α 0 0 Note: The control dimension is the inch column Rev..03

15 LEAD SMALL OUTLINE (300 MIL JEDEC SOIC) Rev..00 D E H Seating Plane e B A C A α L INCHES MILLIMETERS SYMBOL MIN MAX MIN MAX A A B C D E e 0.00 BSC. BSC H L α 0 0 Note: The control dimension is the millimeter column Rev..03

16 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 here in 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 EXAR Corporation Datasheet June Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited. Rev..03