Electronic Components Datasheet Search |
|
CF5072BA-1 Datasheet(PDF) 2 Page - Nippon Precision Circuits Inc |
|
CF5072BA-1 Datasheet(HTML) 2 Page - Nippon Precision Circuits Inc |
2 / 8 page CF5072BA SEIKO NPC CORPORATION —2 FUNCTIONAL DESCRIPTION Oscillator Equivalent Circuit The oscillator can be represented by the equivalent circuit shown below. The crystal unit is connected to XIN, and the other terminal is connected to the LS and RP network. A varicap is added with cathode connected to XR, and anode connected to XC. The control voltage is applied to the VC pin, with high-resistance element connected between VC and XR built-in. Oscillator internal capacitors (design value) Selecting external constants The LS and RP values should be selected such that both (a) the resonance point in the loop formed by LS and C0, CL, CVC is higher than the crystal oscillator frequency, and (b) the resonance point does not satisfy the oscillation condition. (C0 is the crystal shunt capacitance, CL is the oscillator equivalent circuit capacitance, and CVC is the varicap capacitance.) In the oscillator circuit, if the crystal capacitance C0 is 2.85pF, the varicap (CVC) is a HVC350B (Renesas), and the oscillator frequency is 155.52MHz, then values in the order LS = 220nH, RP = 2.2kΩ or LS = 180nH, RP = 1.8kΩ will satisfy the conditions above. The optimal values for LS and RP will vary with crystal charac- teristics, oscillator frequency, and varicap diode, thus the values selected should be thoroughly evaluated. Note. RP is a damping resistor to prevent parasitic oscillation due the combined effects of the external inductor (expander coil) and varicap capacitance/internal capacitance. It is recommended that RP be connected in parallel with LS. Version Internal capacitance [pF] (design value) C1 C2 CF5072BA 11.2 14.4 XC XIN VSS1 XR VC LS RP RVC RS C2 C1 100pF To differential converter VC input X'tal CVC |
Similar Part No. - CF5072BA-1 |
|
Similar Description - CF5072BA-1 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |