Description The Model FDI-4423 Resistor Programmable Precision Quadrature Oscillator has two outputs that are 90 out of phase with each other.  The output frequency of the FDI-4423 is programmable using two resistors or two resistors and two capacitors.  It can be set to any frequency from 0.02 Hz to 20 kHz (and may work as low as 0.002 Hz). The FDI-4423 also has one uncommitted Op Amp that can be used in any way the user wishes.  It is packaged in a small 14-pin DIP package and works from non-critical ±12 Volt to ±18 Volt power supplies. The FDI-4423 will work very similar to the now discontinued Texas Instruments* (Burr-Brown*) 4423P Precision Quadrature Oscillator.  We recommend that the user test any implementation before placing large orders. Features/Benefits: Sine and Cosine Output. Resistor Programmable Outputs. Wide Frequency range: 0.2 Hz to 20 kHz Low Distortion: 0.2% (-54 dB) up to 5 kHz Easy Adjustments Small Size: 0.85" x 0.46" box   Applications Communication systems and electronics Medical electronics equipment and research Aerospace, navigation and sonar * Texas Instruments and Burr-Brown are registered trademarks of their respective companies.   Specifications (@ 25°C and Vs ±15 Vdc) Parameter Test Conditions FDI-4423 Units Min. Typ. Max. Frequency Initial frequency No Adjustment 20.0 21.0 22.0 kHz Frequency Range Using two resistor only 2   20 kHz Using two resistors and two capacitors 0.02   20k Hz Accuracy of Frequency Equation     ±1 ±5 % Stability vs Temperature (1)     ±50 ±100 ppm/°C Quadrature Phase Error     ±0.1   degrees Distortion Sine output (pin 1) 0.2Hz to 5kHz     0.2 % 5kHz to 20kHz     0.5 % Cosine Output (pin 7) 0.2Hz to 5kHz   0.2   % 5kHz to 20kHz   0.8   % Distortion vs Temperature     0.015   %/°C Output Amplitude (sine) At 20kHz 6.5 7 7.5 Vrms vs Temperature   0.05   %/°C vs Supply   0.4   V/V Output Current       20 mA Output Impedance     1   ohm Uncommitted Op Amp Input Offset Voltage     1.1   mV Input Bias Current     20   pA Input Impedance     10 12   ohm Output Impedance     1   ohm Unity Gain Bandwidth     8 10 MHz Output Current       20 mA Power Supply Rated Supply Voltage     ±15   V Supply Voltage Range   ±12   ±18 V Quiescent Current      ±9 ±15 mA Temperature Range Specified   0   +70 °C Storage   -55   +125 °C Pin-Out and Package Data FDI-4423 Typical Circuit Terminal Functions Terminal Description Terminal Name No. Name No. E1 1 Sine Output 8 Frequency Adjustment 2 Frequency Adjustment -Vcc 9 -15VDC 3 Frequency Adjustment +Vcc 10 +15VDC +In 4 Uncommitted Op amp Com 11 Ground -In 5 Uncommitted Op amp 12 Frequency Adjustment Output 6 Uncommitted Op amp 13 Frequency Adjustment E2 7 Cosine Output 14 Frequency Adjustment External Connections 20 kHz Quadrature Oscillator The FDI-4423 does not require and external components to obtain a 20 kHz quadrature oscillation.  The connection diagram is shown in Figure 1. Figure 1 Resistor Programmable Quadrature Oscillator For resistor programmable frequencies in the 2 kHz to 20 kHz frequency range the connection diagram is provided in Figure 2.  Note that only two resisters of equal value are required.  Resistor values are found using Equation 1.    (1) Where R is in KΩ and f is in kHz. Figure 2 Quadrature Oscillator Programmable to 0.02 Hz For oscillation frequencies below 2 kHz the addition of two resistors and two capacitors of equal value is required.  The connections of Figure 3 should be used.  The frequency of oscillation can be found using Equation 2.            (2) Where f is in Hz, C is in µFd, and R is in KΩ. Alternately you can select a capacitance using Figure 4 and calculate the resistance required using Equation 3. Where R is in KΩ, f is in Hz, and C is in µFd. Figure 3 Recommended Capacitor Values For best results use capacitor values shown in Figure 4 for each frequency range. It is important that the two capacitors be as close to the same value as possible. Frequency 2 kHz to 20 kHz 200 Hz to 2 kHz 20 Hz to 200 Hz 2 Hz to 20 Hz 0.2 Hz to 2 Hz 0.02 Hz to 0.2 Hz External Capacitors 0 0.01 µFD 0.1 µFD 1 µFD 10 µFD 100 µFD Figure 4 Recommended Capacitor Types           The FDI-4423 Quadrature Oscillator will only work with non-polarized capacitors with Dissipation Factors of less than 0.01 (or 1%).  Best results will be obtained using ceramic capacitors. Oscillation Amplitude Depending on the frequency it can take a long time to build up to the full output amplitude.  In general the lower the frequency the longer it takes the oscillation to start. There are two methods that can be used to shorten the start up time: Method one involves adding a large value resistor between pins 3 and 14 of the FDI-4423.  The lower this resistor the quicker the oscillation will start but the worse the distortion of the two outputs.  A typical value to try would be 100 KΩ. Method two is similar to method one but the resistor is inserted only during start up of the oscillation.  For instance if a 1 KΩ resistor in series with a push button is installed between pins 3 and 14 and the button pushed during start up the oscillator will start quickly and then will revert to low distortion after the button is released. Low Frequency Operation At low frequencies there may be problems getting the Quadrature Oscillator to start oscillating.  Placing a resistor between pins 3 and 14 can cure this problem.  For instance a 34KΩ resistor can be used in the 0.2 Hz to 2 Hz range. Uncommitted Op Amp Pins 4, 5, and 6 of the FDI-4423 are connected to an Op amp that is available to be used.  It can be used as a buffer or gain stage.  If this Op Amp is not used then pins 4 and 5 of the FDI-4423 should be connected to power supply ground. Package Information We hope the information given here will be helpful. The information is based on data and our best knowledge, and we consider the information to be true and accurate. Please read all statements, recommendations or suggestions herein in conjunction with our conditions of sale which apply to all goods supplied by us. We assume no responsibility for the use of these statements, recommendations or suggestions, nor do we intend them as a recommendation for any use which would infringe any patent or copyright.