Moteur de recherche de fiches techniques de composants électroniques |
|
ADF4217L Fiches technique(PDF) 10 Page - Analog Devices |
|
ADF4217L Fiches technique(HTML) 10 Page - Analog Devices |
10 / 24 page REV. C ADF4217L/ADF4218L/ADF4219L –10– The A and B counters, in conjunction with the dual modulus prescaler, make it possible to generate output frequencies that are spaced only by the Reference Frequency divided by R. The equation for the VCO frequency is as follows: fP B A f R VCO REF IN =× ()+ []× / fVCO = Output frequency of external voltage controlled oscillator (VCO). P = Preset modulus of dual modulus prescaler (8/9, 16/17, and so on). B = Preset divide ratio of binary 11-bit counter (ADF4217L/ ADF4218L), binary 13-bit counter (ADF4219L). A = Preset divide ratio of binary 6-bit A counter (ADF4217L/ ADF4218L), binary 5-bit counter (ADF4219L). fREF IN =Output frequency of the external reference frequency oscillator. R = Preset divide ratio of binary 14-bit programmable reference counter (1 to 16383). The ADF4219L has an R divide of 15 bits. R COUNTER The 14-bit R counter allows the input reference frequency to be divided down to produce the reference clock to the phase frequency detector (PFD). Division ratios from 1 to 16,383 are allowed. The extra R15 bit on the ADF4219L allows ratios from 1 to 32767. PHASE FREQUENCY DETECTOR (PFD) AND CHARGE PUMP The PFD takes inputs from the R counter and N counter and produces an output proportional to the phase and frequency difference between them. Figure 5 is a simplified schematic. R DIVIDER N DIVIDER CP OUTPUT R DIVIDER N DIVIDER D1 Q1 CLR1 U1 U3 DELAY ELEMENT HI UP D2 Q2 CLR2 U2 HI DOWN VP CHARGE PUMP CP CPGND Figure 5. PFD Simplified Schematic MUXOUT AND LOCK DETECT The output multiplexer on the ADF4217L family allows the user to access various internal points on the chip. The state of MUXOUT is controlled by P3, P4, P11, and P12. See Tables IV and VII. Figure 6 shows the MUXOUT section in block diagram form. IF ANALOG LOCK DETECT IF R COUNTER OUTPUT IF N COUNTER OUTPUT IF/RF ANALOG LOCK DETECT RF R COUNTER OUTPUT RF N COUNTER OUTPUT RF ANALOG LOCK DETECT MUX CONTROL MUXOUT DVDD DGND Figure 6. MUXOUT Circuit Lock Detect MUXOUT can be programmed for analog lock detect. The N-channel open-drain analog lock detect should be operated with an external pull-up resistor of 10 k Ω nominal. When lock has been detected, it is high with narrow low going pulses. INPUT SHIFT REGISTER The functional block diagram for the ADF4217L family is shown on page 1. The main blocks include a 22-bit input shift register, a 14-bit R counter, and an N counter. The N counter is comprised of a 6-bit A counter and an 11-bit B counter for the ADF4217L and the ADF4218L. The 18-bit N counter on the ADF4219L is comprised of a 13-bit B counter and a 5-bit A counter. Data is clocked into the 22-bit shift register on each rising edge of CLK. The data is clocked in MSB first. Data is transferred from the shift register to one of four latches on the rising edge of LE. The destination latch is determined by the state of the two con- trol bits (C2, C1) in the shift register. These are the two LSBs, DB1 and DB0, as shown in the timing diagram of Figure 1. The truth table for these bits is shown in Table I. Table I. C2, C1 Truth Table Control Bits C2 C1 Data Latch 00 IF R Counter 01 IF AB Counter (and Prescaler Select) 10 RF R Counter 11 RF AB Counter (and Prescaler Select) |
Numéro de pièce similaire - ADF4217L |
|
Description similaire - ADF4217L |
|
|
Lien URL |
Politique de confidentialité |
ALLDATASHEET.FR |
ALLDATASHEET vous a-t-il été utile ? [ DONATE ] |
À propos de Alldatasheet | Publicité | Contactez-nous | Politique de confidentialité | Echange de liens | Fabricants 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 |