data at 1.8 ghz (3v, 200ma) gain = 15db, p1dbout = 23dbm, nf = 3.3db, rlin > 12db, rlout > 7.7db start499 is a product of the start family (st advanced radio frequency transistor). housed in the ultra miniature 4-lead sot-343 (sc-70) surface mount plastic package, it embeds the state of the art silicon st technology. the amplifier application circuit is designed for use with 30mils thickness fr-4 printed circuit board material. this amplifier is realized with a microstrip line as matching elements and a small number of surface-mount components. a single pin (vcc=3v) for voltage supply is used. a 1 m f bypass capacitor to filter the supply at the common vcc node is also used he transistor's base is connected to the power supply through a choke inductor (microstrip line trl1) and the transistor's collector is connected to the voltage supply through a choke inductor (microstrip line trl4). figure 1: schematic design c b a c2 10n c5 2.2p c4 18p c8 10p c7 1.5p c9 100p c10 10n r3 20 j2 rf_out r2 150 c3 100p j1 rf_in trl1 trl2 trl3 trl4 1 2 vcc l1 12n 3v tr1 start499 c6 2p l2 39n + c1 1 m r1 1.3 k april 2002 1/4 AN1541 application note a medium power amplifier at 1.8 ghz using the npn si start499 transistor
AN1541 - application note 2/4 figure 2: demoboard layout table 1: bill of materials 31.6 mm 42.5 mm com ponent va lue unit size com m ent r1 1.3 kohm 0603 v arious r2 150 ohm 0603 various r3 20 ohm 0603 various c1 1 m f a -cas e v arious c2, c10 10 nf 0603 m urata (series grm 39) c3, c9 100 pf 0603 m urata (series grm 39) c4 18 pf 0603 m urata (series grm 39) c5 2.2 pf 0603 m urata (series grm 39) c6 2 pf 0603 m urata (series grm 39) c7 1.5 pf 0603 m urata (series grm 39) c8 10 pf 0603 m urata (series grm 39) l1 12 nh 0603 m urata (series lqp11a) l2 39 nh 0603 murata (series lqw 1608a) j3 dc connector various j1, j2 142-0701-881 s m a connector johnson tr1 start499 sot343 stmicroelectronics substrate fr4 h = 30 mils various figure 3: output power at 1db compression point 10 11 12 13 14 15 16 5 10152025 poutput (dbm) gain (db) p1dbcp (+23 dbm)
AN1541 - application note 3/4 s-parameters -16 -14 -12 -10 -8 -6 -4 -2 0 1600 1700 1800 1900 2000 frequency (mhz) s11 (db) -24 -22 -20 -18 -16 -14 -12 -10 1600 1700 1800 1900 2000 frequency (mhz) s12 (db) 11 12 13 14 15 16 17 18 1600 1700 1800 1900 2000 frequency (mhz) s21 (db) -12 -10 -8 -6 -4 -2 0 1600 1700 1800 1900 2000 frequency (mhz) s22 (db)
AN1541 - application note 4/4 information furnished is believed to be accurate and reliable. however, stmicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of stmicroelectronics. specification mentioned in this publication are subject to change without notice. this publication supersedes and replaces all information previously supplied. stmicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of stmicroelectronics. the st logo is a trademark of stmicroelectronics ? 2002 stmicroelectronics - printed in italy - all rights reserved stmicroelectronics group of companies australia - brazil - china - finland - france - germany - hong kong - india - italy - japan - malaysia - malta - morocco - singapore - spain - sweden - switzerland - united kingdom - u.s.a. http://w ww.st.com
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