AN3001 MA-COM | Alldatasheet
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Technical content
Visit www.macomtech.com for additional data sheets and product information. changes to the product(s) or information contained herein without notice. diodes. This can also be noted on the Smith Chart. through the vector modulator.
- Case 1. If the diodes in the bottom VVA are set to an impedance of 50 ohms, the bottom VVA will be in a high loss state. The output of the top VVA will have a phase of 0 ° or 180°, depending on the impedance of the terminating diodes. See the “A” or “/A” labels.
- Case 2. If the diodes in the top VVA are set to an impedance of 50 ohms, the top VVA will be in a high loss state. The output of the bottom VVA will have a phase of -90 ° or 90°, depend- ing on the impedance of the terminating di- odes. See the “B” or “/B” labels.
- Case 3. If the output of the top VVA has a phase of 0° with a magnitude of 1, and the out- put of the bottom VVA has a phase of 90° with a magnitude of 1, the re sultant vector will have a magnitude of 1.414 (square root of 2) at an angle of 45°. Definition of RF Parameters It is helpful to define some of the parameters used to specify the electrical performance of a vector modulator, so that the specifications are clearly understood. Note that this type of vector modulator is designed to have continuous phase shift over 360°. Reference Loss : This is the minimum loss where all phases from 0 ° to 360 ° are available. This is measured at the center fr equency of the specified band. Attenuation Range : This is the attenuation (relative to the reference loss), where the performance of the vector modulator is defined. For example, if a vector modulator has an attenuation range of 10 dB, and a reference loss of 12 dB, the vector modulator will operate over an absolute loss range between 12 and 22 dB. Note that in the case of SA90-0001, the vector modulator has a higher at- tenuation range than the specified range, but the attenuation is difficult to control, and the phase line- arity and amplitude ripple start to degrade. Frequency Band (MHz) Band Model Number Model Number of Prototype with Driver Availability 925 - 960 GSM MAMDCC0005 MAMDCC0005-DC000 Q2 2002 1930 - 1990 PCS MAMDCC0002 MAMDCC0002-DC000 In Stock 2040 - 2240 UMTS SA90-0001 SA90-0001-DC000 In Stock
Table 1. Selection Guide for Vector Modulator
Visit www.macomtech.com for additional data sheets and product information. changes to the product(s) or information contained herein without notice. components on the schematic. It is important to have the inductors as close to the vector modulator as possible. between the inductors and as close as possible to the inductors, as shown in the PC board layout. scale package (CSP) was used to minimize the amount of PC board space that the end user would require. circuit. The lines in the bias circuit should be approximately 6 mils wide to minimize cross coupling. vices, but low enough to avoid damaging internal circuitry during proper solder reflow operations. Figure 3. Schematic of Dual Linearizer Driving Vector Modulator
Visit www.macomtech.com for additional data sheets and product information. changes to the product(s) or information contained herein without notice. Table 2. Selection Table for Bias Inductors Figure 4. Transfer Function of Test to Determine Reference Loss
Visit www.macomtech.com for additional data sheets and product information. changes to the product(s) or information contained herein without notice. Figure 5. Phase and Attenuation of MAMDCC0006, Vector Modulator Linearized with
- Tic marks on x,y axes refer to reflecti on coefficient in increments of 0.1V Reflection coefficients vary from –0.5 to +0.5 on both
- Data is for vector modulators driv en by linearizers per attached schematic.
- Inputs to the linearizers vary from 0 to 5V.
- The phase with the inputs to both linearizers se t to +5V is arbitrarily called zero degrees.
Visit www.macomtech.com for additional data sheets and product information. changes to the product(s) or information contained herein without notice. Figure 6. Phase and Attenuation of MAMDCC0006 vs. Bias Current
- The phase with the inputs to both linearizer s set to +15V is arbitrarily called zero.