CIRCUIT COLLECTION : OSCILLATORS

SECTION 1 .:. AUDIO FREQUENCY

CIRCUIT 1-1 : Wien Bridge Sine Wave Oscillator

Source: National Semiconductor, An Applications Guide for Op Amps

FEATURES :

• high purity sine-wave output
• minimum circuit complexity

CIRCUIT 1-2 : Phase Shift Oscillator

Source: National Semiconductor, LM 380 Datasheet

FEATURES :

• 3 x RC Phase Shifter
• Freq. approx. 4 kHz

CIRCUIT 1-3 : Wien Bridge Oscillator with AGC

Source: Texas Instruments, Op Amps For Everyone

FEATURES :

• The op amp is configured as an ac amplifier to ease biasing problems
• The diode rectifies the output voltage and applies it to the voltage divider formed by R1, R2

CIRCUIT 1-4 : Quadrature Oscillator

Source: Texas Instruments, Op Amps For Everyone

FEATURES :

• When R1xC1 = R2xC2 = R3xC3, the circuit oscillates at ω = 2πf = 1/RC.

CIRCUIT 1-5 : Wien Bridge Oscillator with Nonlinear Feedback

Source: Texas Instruments, Op Amps For Everyone

FEATURES :

• distortion doesn’t occur

CIRCUIT 1-6 : Classical Phase Shift Oscillator

Source: Texas Instruments, Op Amps For Everyone

FEATURES :

• undistorted sine wave available at the output

CIRCUIT 1-7 : Buffered Phase Shift Oscillator

Source: Texas Instruments, Op Amps For Everyone

FEATURES :

• undistorted sine wave available at the output

CIRCUIT 1-8 : Bubba Oscillator

Source: Texas Instruments, Op Amps For Everyone

FEATURES :

• The Bubba oscillator is another phase shift oscillator
• Four RC sections require –45° phase shift per section
• Very low distortion sine waves can be obtained

CIRCUIT 1-9 : Triangle Oscillator

Source: Texas Instruments, Op Amps For Everyone

FEATURES :

• The triangle oscillator produces triangle waves and square waves

SECTION 2 .:. CRYSTAL OSCILLATORS

CIRCUIT 2-1 : Typical Gate Oscillator

Source: Fairchild Semiconductor, HCMOS Crystal Oscillators

HINTS :

• Choose R2 to have approx. XC at Freq. of Operation
• Use equal capacitor values for Ca and Cb

CIRCUIT 2-2 : Gate Oscillator for Higher Frequencies

Source: Fairchild Semiconductor, HCMOS Crystal Oscillators

HINTS :

• If the Freq. is larger than 4 MHz, the additional Phase-Shift is done by the delay of the Gate.
• The value of C_L is approx. 1/ωC where ω=2pf, but not less than about 20 pF.

CIRCUIT 2-3 : Gate oscillator with improved stability

Source: Fairchild Semiconductor, HCMOS Crystal Oscillators

HINTS :

• A small C in series with the xtal acts as the xtal load and isolates the xtal from the rest.
• Ca and Cb are made large to swamp out the effects of Temp. / Supply Voltage change.

CIRCUIT 2-4 : Parallel Mode Overtone Circuit

Source: Fairchild Semiconductor, HCMOS Crystal Oscillators

HINTS :

• This circuit operates in the parallel mode just as the Pierce oscillator above.
• The resonant circuit LA-CB is an effective short at the fundamental frequency
• It is tuned somewhat below the deferred crystal overtone frequency.
• C_L is chosen to suppress operation in the fundamental mode.
• L_A may be tuned to produce maximum output.

CIRCUIT 2-5 : 74C14 XTAL Oscillator 100 kHz

Source: Linear Technology, Circuit Techniques for Clock Sources

HINTS :

• Please read the Application Note.

CIRCUIT 2-6 : 4049 XTAL Oscillator 1 MHz

Source: Linear Technology, Circuit Techniques for Clock Sources

HINTS :

• Please read the Application Note.

CIRCUIT 2-7 : 74LS04 XTAL Oscillator 10 MHz

Source: Linear Technology, Circuit Techniques for Clock Sources

HINTS :

• Please read the Application Note.

CIRCUIT 2-8 : 74LS04 XTAL Oscillator 5 MHz

Source: Linear Technology, Circuit Techniques for Clock Sources

HINTS :

• Please read the Application Note.

CIRCUIT 2-9 : 2N3904 XTAL Oscillator 20 MHz

Source: Linear Technology, Circuit Techniques for Clock Sources

HINTS :

• Please read the Application Note.

CIRCUIT 2-10 : LT1016 XTAL Oscillator 1...10 MHz

Source: Linear Technology, Circuit Techniques for Clock Sources

HINTS :

• Please read the Application Note.

CIRCUIT 2-11 : LT1016 XTAL Oscillator 10...25 MHz

Source: Linear Technology, Circuit Techniques for Clock Sources

HINTS :

• Please read the Application Note.

CIRCUIT 2-12 : 2N3904 XTAL Oscillator

Source: Linear Technology, Circuit Techniques for Clock Sources

HINTS :

• Please read the Application Note.

CIRCUIT 2-13 : Temperature Compensated Crystal Oscillator

Source: Linear Technology, Circuit Techniques for Clock Sources

HINTS :

• Please read the Application Note.

CIRCUIT 2-14 : Voltage Controlled Crystal Oscillator (VCXO)

Source: Linear Technology, Circuit Techniques for Clock Sources

HINTS :

• Please read the Application Note.

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