User manual PHILIPS BLF574

[. . . ] AN10714 Using the BLF574 in the 88 MHz to 108 MHz FM band Rev. 01 -- 26 January 2010 Application note Document information Info Keywords Abstract Content BLF574, 600 MHz performance, high voltage LDMOS, amplifier implementation, Class-B CW, FM band, pulsed power This application note describes the design and the performance of the BLF574 for Class-B CW and FM type applications in the 88 MHz to 108 MHz frequency range. NXP Semiconductors AN10714 Using the BLF574 in the 88 MHz to 108 MHz FM band Revision history Rev 01 Date 20100126 Description Initial version AN10714_1 © NXP B. V. All rights reserved. Application note Rev. 01 -- 26 January 2010 2 of 21 NXP Semiconductors AN10714 Using the BLF574 in the 88 MHz to 108 MHz FM band 1. [. . . ] In general, the following areas of the circuit have the most impact on the circuit operating frequency and PL(1dB) performance. The modification areas are listed in order of sensitivity, with the most sensitive tuning elements listed first. Effect of changing the output capacitors (C12 and C13): · This is a key tuning point in the circuit. This point has the strongest influence on the trade-off between efficiency and linearity. Effect of the length of the output balun (B2): · The frequency can be shifted by modifying this element. Typically, the longer the balun, the more the response is shifted to lower frequencies. Conversely, a short balun shifts the response to higher frequencies. Effect of changing the output 4 : 1 transformers (T3 and T4): · The frequency can be shifted by modifying these elements. In general, longer transformers shift the whole response to a lower frequency. Shortening the transformers shifts the response to higher frequencies. Changes in efficiency and PL(1dB) is seen when the characteristic impedance of these transformers is changed. Effect of changing the output capacitor (C14): · Changing this output capacitor has an effect of tilting the response over the band. The efficiency or PL(1dB) performance can be made more consistent over the band by modifying C14. Effect of adding capacitance off the drain (C10, C11, C15, and C16): · A small adjustment in the trade-off between efficiency and PL(1dB) performance can be made by changing these capacitors. AN10714_1 © NXP B. V. All rights reserved. Application note Rev. 01 -- 26 January 2010 10 of 21 NXP Semiconductors AN10714 Using the BLF574 in the 88 MHz to 108 MHz FM band 4. RF performance characteristics 4. 1 Continuous wave Table 2. Class-B performance of the BLF574 at 50 V/600 W This table summarizes the Class-B performance of the BLF574 at 50 V, IDq = 200 mA and Th = 25 °C. Input and output impedance The BLF574 input and output impedances are given in Table 3. These are generated from a first order equivalent circuit of the device and can be used to get the first-pass matching circuits. Table 3. Input and output impedance per section Input (Zi) 2. 020 - j26. 216 2. 020 - j13. 087 2. 020 - j8. 701 2. 020 - j6. 500 2. 021 - j5. 175 2. 021 - j4. 286 2. 022 - j3. 647 2. 023 - j3. 164 2. 023 - j2. 768 2. 024 - j2. 480 2. 025 - j2. 227 2. 026 - j2. 014 2. 028 - j1. 832 2. 029 - j1. 673 2. 030 - j1. 534 2. 032 - j1. 410 2. 033 - j1. 299 2. 035 - j1. 199 2. 037 - j1. 108 2. 039 - j1. 025 Output (Zo) 4. 987 - j0. 241 4. 947 - j0. 477 4. 882 - j0. 705 4. 794 - j0. 922 4. 685 - j1. 125 4. 559 - j1. 310 4. 418 - j1. 478 4. 266 - j1. 626 4. 106 - j1. 755 3. 941 - j1. 864 3. 773 - j1. 955 3. 605 - j2. 028 3. 439 - j2. 084 3. 275 - j2. 126 3. 116 - j2. 154 2. 962 - j2. 170 2. 814 - j2. 176 2. 673 - j2. 172 2. 538 - j2. 159 2. 410 - j2. 140 25 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425 450 475 500 Frequency (MHz) The convention for these impedances is shown in Figure 10. They indicate the impedances looking into half the device. Zo Zi 001aak541 Fig 10. [. . . ] All rights reserved. Application note Rev. 01 -- 26 January 2010 19 of 21 NXP Semiconductors AN10714 Using the BLF574 in the 88 MHz to 108 MHz FM band 11. Legal information 11. 1 Definitions Suitability for use -- NXP Semiconductors products are not designed, authorized or warranted to be suitable for use in medical, military, aircraft, space or life support equipment, nor in applications where failure or malfunction of an NXP Semiconductors product can reasonably be expected to result in personal injury, death or severe property or environmental damage. NXP Semiconductors accepts no liability for inclusion and/or use of NXP Semiconductors products in such equipment or applications and therefore such inclusion and/or use is at the customer's own risk. [. . . ]