 |
Motor de Búsqueda de Datasheet de Componentes Electrónicos |
|
|
Motor de Búsqueda de Datasheet de Componentes Electrónicos |
|
ADF4213BRU Datasheet(PDF) 9 Page - Analog Devices |
|
||||||||||||||||||||||||||||||
ADF4213BRU Datasheet(HTML) 9 Page - Analog Devices |
|
|
9 / 20 page  REV. A ADF4210/ADF4211/ADF4212/ADF4213 –9– TEMPERATURE – C 100 –40 0 20 40 60 80 –100 –70 –80 –90 –60 –20 VDD = 3V VP = 5V TPC 19. ADF4213 Reference Spurs vs. Temperature (836 MHz, 30 kHz, 3 kHz) CIRCUIT DESCRIPTION REFERENCE INPUT SECTION The reference input stage is shown below in Figure 2. SW1 and SW2 are normally-closed switches. SW3 is normally-open. When power-down is initiated, SW3 is closed and SW1 and SW2 are opened. This ensures that there is no loading of the REFIN pin on power-down. BUFFER TO R COUNTER REFIN 100k NC SW2 SW3 NO NC SW1 POWER-DOWN CONTROL NC = NO CONNECT Figure 2. Reference Input Stage RF/IF INPUT STAGE The RF/IF input stage is shown in Figure 3. It is followed by a 2-stage limiting amplifier to generate the CML (Current Mode Logic) clock levels needed for the prescaler. AVDD AGND 2k 2k 1.6V BIAS GENERATOR RFINA RFINB Figure 3. RF/IF Input Stage PRESCALER (P/P + 1) The dual modulus prescaler (P/P + 1), along with the A and B counters, enables the large division ratio, N, to be realized (N = PB + A). The dual-modulus prescaler, operating at CML levels, takes the clock from the RF/IF input stage and divides it down to a manageable frequency for the CMOS A and B counters in the RF and If sections. The prescaler in both sections is programmable. It can be set in software to 8/9, 16/17, 32/33, or 64/65. See Tables IV and VI. It is based on a syn- chronous 4/5 core. RF/IF A AND B COUNTERS The A and B CMOS counters combine with the dual modulus prescaler to allow a wide ranging division ratio in the PLL feedback counter. The counters are specified to work when the prescaler output is 200 MHz or less, when VDD = 5 V. Typically, they will work with 250 MHz output from the prescaler. Thus, with an RF input frequency of 2.5 GHz, a prescaler value of 16/17 is valid, but a value of 8/9 is not valid. Pulse Swallow Function The A and B counters, in conjunction with the dual modulus prescaler make it possible to generate output frequencies which are spaced only by the Reference Frequency divided by R. The equation for the VCO frequency is as follows: fVCO = [(P × B) + A] × f REFIN/R fVCO = Output Frequency of external voltage controlled oscillator (VCO). P = Preset modulus of dual modulus prescaler (8/9, 16/17, etc.). B = Preset Divide Ratio of binary 13-bit counter (3 to 8191). A = Preset Divide Ratio of binary 6-bit A counter (0 to 63). fREFIN = External reference frequency oscillator. R = Preset divide ratio of binary 15-bit programmable refer- ence counter (1 to 32767). 13-BIT B- COUNTER 5-BIT A- COUNTER PRESCALER P/P + 1 FROM RF INPUT STAGE MODULUS CONTROL N = BP + A LOAD LOAD TO PFD Figure 4. RF/IF A and B Counters RF/IF COUNTER The 15-bit RF/IF R counter allows the input reference fre- quency to be divided down to product the input clock to the phase frequency detector (PFD). Division ratios from 1 to 32767 are allowed. |
Número de pieza similar - ADF4213BRU |
|
Descripción similar - ADF4213BRU |
|
|
|
Enlace URL |
| Política de Privacidad |
| ALLDATASHEET.ES |
| ¿ALLDATASHEET es útil para Ud.? [ DONATE ] |
Todo acerca de Alldatasheet | Publicidad | Contáctenos | Política de Privacidad | Intercambio de Enlaces | Lista de Fabricantes 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 |
Spanish ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
