Quartz Crystal Units n Oscillation Circuits The following circuit diagrams are examples of the oscillation circuits recommended when crystal units are used. After determining your frequency range and overtone specifications, you can then establish various circuit elements and conditions depending on the choice of either an IC circuit or discrete transistor. IC circuit constants or circuit configurations vary among the different IC manufactures and such factors may have a subtle effect upon the oscillation of a crystal unit. For further details, please contact us. Crystal oscillation circuits for PLL VCC +5V 1. Frequency Range : 12 to 20 MHz Overtone Order : Fundamental Load Capacitance CL = 20 pF 22kΩ 8.2kΩ 1kΩ 0.01μF 1kΩ 0.01μF 47μF 0.01μF 5pF 100pF OUTPUT 0.01μF 10kΩ 24pF 100pF 1kΩ 1kΩ 4.7kΩ 2. Frequency Range : 3 to 25 MHz Overtone Order : Fundamental 74HCUO4AP 2 1 Frequency Range(MHz) C1=C2(pF) R1(Ω) Load Capacitance(pF) 3 to 4 33 4.7 k 20 4 to 5 33 3.3 k 20 5 to 6 33 2.2 k 20 6 to 9 22 1.0 k 16 9 to 10 22 470 16 10 to 15 15 470 12 15 to 20 15 470 12 20 to 25 10 470 10 C1=C2(pF) R1(Ω) Load Capacitance(pF) 3 to 4 33 6.8 k 20 4 to 5 33 4.7 k 20 5 to 6 33 3.3 k 20 6 to 9 22 2.2 k 16 9 to 10 22 1.0 k 16 10 to 15 15 470 12 15 to 20 10 330 12 20 to 25 7 330 10 C2 C1 7SU04F 2 2 4 IC1 R1(Ω) Load Capacitance(pF) 1.0 k 12 30 to 40 10 680 10 40 to 50 7 330 8 OUTPUT 1M *Please use an un-buffered type inverter. R1 C2 C1 2 15 4 IC2 7SHU04 2 4 IC1 C1=C2(pF) *Please use an un-buffered type inverter. 7SU04F 7SHU04 25 to 30 OUTPUT R1 4. Frequency Range : 25 to 50MHz Overtone Order : Fundamental Frequency Range(MHz) 4 1M 3. Frequency Range : 3 to 25 MHz Overtone Order : Fundamental Frequency Range(MHz) 3 4 OUTPUT IC2 1M R1 *Please use an un-buffered type inverter. C1 C2 cu07_091224_circuit1_e Quartz Crystal Units n Oscillation Circuits 7SHU04 5. Frequency Range : 30 to 60 MHz Overtone Order : 3rd overtone 7SHU04 IC1 IC2 2 2 4 4 OUTPUT 1M Frequency Range (MHz) R1(Ω) Load Capacitance (pF) C1(pF) C2(pF) L1(μH) 30 to 40 10 18 to 10 2.2 820 10 40 to 50 7 15 to 10 1.5 470 8 50 to 60 5 15 to 10 1.0 330 8 R1 1000pF C1 C2 6. Frequency Range : 16 to 80 MHz max Overtone Order : 3rd, 5th overtone Load Capacitance CL : Series resonance L1 *Please use an un-buffered type inverter. VCC +9V R2 22kΩ Reference electric specification for Tr fT : 900MHz COB : 1.4pF 1000pF C2 15 to 330pF L1 15 to 38t R1 4.7kΩ C1 22pF 7. Frequency Range : 80 to 140 MHz max Overtone Order : 3rd, 5th overtone Load Capacitance CL : Series resonance R3 10kΩ R4 820Ω C3 0.01μF OUT PUT C4 30 to 68pF Cv L1 8 to 10t C4 0.01μF C5 0.01μF 2 to 5t Reference electric specification for Q1 FT : 900MHz COB : 1.4pF C7 68pF Tr Q1 R1 680Ω C1 Open – 33pF OUT PUT C3 2 to 3pF C4 7 to 15pF C2 0.02pF R2 4.7kΩ R3 10kΩ CV C5 7 to 22pF T1 R4 3 to 4t 10kΩ T1 1 to 2t R5 220Ω C6 0.02μF E VCC +9V cu08_090920_circuit2_e Quartz Crystal Units n Oscillation Circuits OUT PUT 8. Example of Un-buffered IC Oscillation Circuit Connection 0.01μF Vdd 8 7 6 5 1 2 Rf 3 4 Gnd Rd To prevent coupling between input and output: • Position input pin 3 at a distance from output pin 7. • Inactivate the inverter at the center. C2 Rf=1MΩ Rd=100 to 10kΩ C1, C2=5 to 33pF C1 9. Example of IC Internal Oscillation Circuit Connection C-MOS To achieve correct operation: • When IC has Resistance R1 already embedded, its mounting is unnecessary. • Resistance R2 is necessary for the prevention of abnormal oscillation. • Use this circuitry as the base pattern. • Install Resistance R2 on to the output side after checking the IC terminal function. Xin Xout R1 R2 C1 R1=1MΩ R2=100 to 10kΩ C1, C2=5 to 33pF C2 Note for Mounting: 1. Use the shortest distance for lines connecting parts, including ground lines, in order to prevent the inclusion of unnecessary stray capacitance. 2. Do not allow any part of the oscillation circuit to cross over a signal line of any other circuit on the same circuit board. cu09_091224_circuit3_e