Datasheet ADF5000 (Analog Devices) - 8

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ADF5000 Data Sheet APPLICATION CIRCUIT
The ADF5000 can be connected either single-ended or differ- The positive input pin of the OP184 is biased at half the ADF4156 entially to any of the Analog Devices PLL family of ICs. It is charge pump supply (VP). This can be easily achieved using a recommended that a differential connection be used for best simple resistor divider, ensuring sufficient decoupling close to performance and to achieve maximum power transfer. The the +IN A pin of the OP184. This configuration, in turn, allows application circuit shown in Figure 10 shows the ADF5000 the use of a single positive supply for the op amp. Alternatively, used as the RF prescaler in a microwave 12 GHz PLL loop. The to optimize performance by ensuring a clean bias voltage, a low ADF5000 divides the 12 GHz RF signal down to 6 GHz, which noise regulator such as the ADP150 can be used to power the is input differentially into the ADF4156 PLL. An active filter resistor divider network or the +IN A pin directly. topology, using the OP184 op amp, is used to provide the wide tuning ranges typically required by microwave VCOs.
1.8nF 10pF 0.1µF 330Ω 47nF VDD1 VDD2 ADF4156 DECOUPLING PLL INTEGRATED ADF5000 RFOUT RFINA 220Ω RFIN CP PRESCALER 1kΩ OP184 V RFOUT RF P/2 INB OP AMP 820pF GND 1µF 1.8nF MICROWAVE 6dB ATTENUATION PAD VCO 18Ω RFOUT VTUNE 37Ω 150Ω 150Ω 18Ω
010
12GHz OUT
09129- Figure 10. ADF5000 Used as the RF Prescaler in a Microwave 12 GHz PLL Loop Rev. A | Page 8 of 12 Document Outline Features Applications General Description Functional Block Diagram Table of Contents Revision History Specifications Absolute Maximum Ratings ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Evaluation Board PCB PCB Material Stack-Up Bill of Materials Application Circuit Outline Dimensions Ordering Guide