PH97005

PH97005 PHILIPS | Alldatasheet

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Philips Semiconductors B.V. Low cost DECT Po wer Amplifier PH9 7005 Prelim in ary A pplication No te RNR-T4 5-97-M-0 931 Au th or L.C. Colussi Novemb er 2 1, 19 97 Discre te Se micon ducto rs Nijmege n Gerstwe g 2, 65 34 AE Nijme gen Th e Netherland s Key words PA, DEC T , DPO, B FG4 25W, B FG2 1W Abs trac t Ap plicatio n of n ew5 th g en eration discrete bipo la r RF tra nsistors facilitates d esign o f a low cost two-stage p owe r amp lifier f o r DECT syste ms, h aving a p owe r gain of 26 dB a nd an overall efficie ncy b ette r than 4 0%. T he amp lifie r ope ra te s f rom a sing le supp ly volta ge, in clude s bias ci r cui try for loa d pow er ad ju stmen t an d on/off switch in g and i s mou nted on a b il ay er p cb, requ irin g 10 x 20 mm . A descrip tion is given of the circu it desig n and the b oard layo ut, includ in g mea sureme nt results.

Philips Semiconductors B.V. Low cost DECT Power Amplifier PH97005 RNR-T45-97-M-0931 I NTRODU CTI ON Th is n ot e des cr ib es the ap pl ic at io n of t wo of th e ne w 5 th gen er at ion si li co n bi pol ar RF tr an si st or s i n SOT3 43R pl as ti c SMD p ack age i n a two- st age p owe r amp li fi er (PA ), des ig ned f or u se i n DEC T c or dl es s t e le pho ne sy st ems . Th ese t ra ns is to rs , man uf act ur ed ac co rd ing t o the ne w do ubl e- po ly pr oce ss, ar e cha ra ct er is ed by t he ir h ig h tr an si ti on f r equ enc y (f T > 20 GH z) at lo w su ppl y volt ag es , re sul t in g in a s upe ri or powe r ga in at mi cr owav e f r eq uen ci es, usu al ly a f i el d de di cat ed t o GaA s- dev ic es. Tw o l ay er s of p ol ysi l ic on ar e us ed: one f or c ont ac t ing t he b ase , yi el di ng a l ow ba se resi s tan ce a nd one t o for m t he e mit t er , re su lt i ng in a s te ep em it te r do pe pr of i le an d an ef f ect i ve em it t er wi dt h of 0 .5 m m. A bu ri ed N- l aye r ( c ol l ect or ) is pl ace d wi th in a P- su bst r at e, wh ic h is con nec te d to t he e mit t er pa ck age l ea d, wh ic h ena bl es th e di e t o b e pl ace d on t he g rou nd pl an e, r ed uci ng e mit t er i nd uct an ce an d t h erm al r esi s ta nce . Fi gu re 1 sh ows a cr os s se ct io n of a do ubl e- po ly bur i ed la ye r t r an si st or . F ig u re 1 :C ro ss secti o n an d p acka g e of th e d ou b le -p o ly b u ri ed l a yer RF t ra nsi sto rs. Wi th o nl y t wo do ubl e- po ly tr an si st or s a comp le te a mpl if i er l i ne- up ca n be real i sed , of f er in g 26 d Bm of o ut put powe r wi th mo re t ha n 26 dB po wer g ai n. T h e ampl i fi er re q u i re s a si ngl e su ppl y volt ag e of 3 .6 V a nd typi ca ll y ha s 44% ef f ic ie ncy . T he bi as in g c i rc ui tr y us es on ly o ne NPN t ra ns is to r pai r , whi c h a ls o pe rf or ms lo ad po wer a dj ust me nt an d on/ of f s wi tc hi ng func ti on s. Th ank s t o t he l ow c ompo nen t co unt and s imp le ma tc hi ng ne tw ork s the en ti re a mpl if i er ( in cl udi ng b ia s par t) onl y mea su res 1 0 x 20 mm. As c ompa re d t o a p rev i ous d emon st ra ti on b oar d, P H960 60 (Pre li mi nar y Ap pl ic at io n Not e RNR-T4 5-96 -T-83 8) t hi s on e of fer s lowe r add it i ona l co mpo nent co unt , bu t is le ss s ui ta bl e f o r PHS a ppl i cat i on. Th e mai n f e at ur es of th e PA ar e: - l ow co mpon ent co unt - s mal l si ze - h ig h eff i ci en cy - s in gl e sup pl y ope ra ti on 1 b as e 2 e mitt er 3 c ol le ct or 4 e mitt er

Philips Semiconductors B.V. Low cost DECT Power Amplifier PH97005 RNR-T45-97-M-0931 CHAR ACTER IS TIC S (unles s otherwis e specified the oper ating frequency is 1. 89 GHz, the supply voltage i s 3.6 V, the input power is 0 dBm and the per iod is 10 ms with a duty cycle of 1:8) Pa rame te r Sp eci fi ca ti on Ty pi cal Con di ti on Gen er al p a r a m e t ers Su ppl y vo lt ag e ( Vs )3 . 2 £ 3 .6 £ 4 .2 V Con tr ol vol t age ( Vc )o n s ta te : 3. 6 V of f s ta te : 0 V Fr eq uen cy rang e 1. 88 - 1.9 2 GHz Ty pe of ope ra ti on pu ls ed du ty c yc le £ 50% So urc e an d l oa d im peda nc e5 0 W Po wer g ai n ( Gp) ‡ 26 dB 26 .3 d B P o = 26 dB m Out pu t po wer ( Po) ‡ 26 dB m 26 .3 d Bm Av g. s upp ly c ur re nt 11 mA P o = 26 d Bm Ef f ic ie ncy ‡ 40% 44 % P o = 26 d Bm I npu t VSWR 2 : 1 I sol at i on (r el a tive t o in pu t po w er ) ‡ 50 dB 57 d B Vc = 0 V Sp uri ou s £ -6 0 dBc V s = 3. 2. .4 .2 V VSWR 6 : 1, al l p has es Le aka ge cu rr en t in o ff - st at e £ 10 mA Vc = 0 V Har mon ic s: 2 nd rd £ -3 0 dBm £ -3 0 dBm - 34 dBm - 13 dBm Lo ad mi sma tc h: No de gr ada ti on P o = 26 d Bm, Vs £ 4. 5 V VSWR 6 : 1, al l p has es Pr in te d ci rc ui t bo ar dF R 4 b i l ay er ta n d= 0. 02 ) Di men si ons 10 x 2 0 mm (i n cl u di n g bi as circu it ry) T ab l e 1: C ha ra cte ri stics o f th e DE CT P A PH 97 0 05 .

Philips Semiconductors B.V. Low cost DECT Power Amplifier PH97005 RNR-T45-97-M-0931 CI RCUI T DES CRIP T I ON Fi gu re 2 s hows c i rcu it di agr am of th e DECT PA i nc lu di ng bo th RF t r ans is to rs , mat ch in g ci rc ui ts an d bi asi ng c ir cu it . T he ap pen di x con ta in s t h e par t l is t o f t h e dem o b oar d. F ig u re 2 :C ircu it d ia g ra m o f t he D EC T PA d e mo bo a rd P H9 7 00 5 . RF tra nsi st or s Th e RF ch ain o f the PA c ons is ts o f two tran si st or s ta ges : a BF G 425 W ( Q1) wid eba nd tra nsi st or , op er at in g i n cla ss A an d a B FG21 W ( Q2) , o per at in g in c la ss AB . I n acc or dan ce wi t h t he a bov e se tt i ngs t he me asu re d sou rc e and l oad i mp edan ce s of b ot h t ra nsi st or s ar e gi ve n in t abl e 2. Tr ans is to r So urc e imp eda nce ( Zs) Lo ad imped anc e ( Zl) BF G425 W (V ce= 3. 6 V; Ic= 30 m A; f= 1. 89 G Hz) 12 + 0 .7 j W 52 + 1 02 j W BF G21W (V ce= 3. 6 V; Po= 26 d B m; f =1 .8 9 GH z) 8 - 4 .5 j W 12 - 3. 5 j W T ab l e 2 : S ou rce a n d lo ad i mp ed a n ce s o f th e ap p li e d RF tr an sist or s. Sma ll si gna l S- par ame te r da ta f or t he B FG42 5W as wel l a s la rg e si gna l Sp ic e par ame te rs o f bo th t he BF G42 5W a nd the BF G21W ar e av ail ab le o n f l op py di sc . Th e RF tr an si st or s hav e t w o emi tt er s lead s, wh ic h hav e t o b e car ef ul l y gr oun ded t o en sur e st ab le o per at i on and p er fo rma nce a cc ord in g t o s pec if i cat i on. Typ ic al l y, t he i ndu ct an ce of th e vi as h as t o be kept b el ow 0. 1 nH. Vs Vc RF in RF out TL1 TL2 TL3 TL4 C3 C5 TL5 TL6 TL7 TL8 C6 C8 C10 C11 C12 C13 Q3a Q3b

Philips Semiconductors B.V. Low cost DECT Power Amplifier PH97005 RNR-T45-97-M-0931 I mped anc e matc hi ng Th e imp eda nce ma tc hi ng pa rt con si st s of th re e s epa ra te s ect i ons : the inpu t, th e in te rs ta ge an d t he ou tp ut ma tc hi ng ne two rk s. T he pu rp ose o f thes e net wor ks is t o en abl e t h e RF tran si st or s to gi ve o pt imu m p er fo rma nce w it h re spe ct t o po wer g ai n, o ut put powe r an d ef fi ci en cy. Fo r t una te ly , t he imped anc e le vel s of th e ap p l i ed do ubl e- po ly tr an si st or s ar e n ot e xc ept i ona ll y hi gh o r lo w, s o t hey ’r e r a th er e asy t o ma tc h. Dec ou pl in g i s d one by usi ng c apa ci to rs C1 , C4 , C6, C8, C 11 an d C12, whi ch a re seri es r eso nan t at 1. 9 GHz. C apa ci to rs C7 ( wi th r es is to r R3 ) and C 9 are u sed t o su ppr es s lo w f re que ncy i ns ta bi li t y. At t h e inp ut s i de sh unt cap aci t or C2 a nd se ri es t ra nsmi ss io n li ne T L1 mat c h t he 5 0 W sou rc e t o t he ba se of Q1. B ase r es is to r R1 is us ed f o r bi as in g and ha s no ef f ect on mat ch in g. F ig . 3a : In pu t mat chi ng . Be twe en the co ll ec to r of Q1 and t he b ase o f Q2 mat ch in g is d one b y se ri es t ra nsm is si on lin e T L2 , sh unt ca pac it or C3 and s er ie s t r an smi ss io n li ne s TL4 a nd TL 6. B ot h s hu nt c apa ci to rs C3 a nd C5 ( par t ly ) co mpen sa te t he inf lu enc e of b ia s st ubs TL3 a nd TL5 , whi c h are b ot h sho rt er th an a qua rt er wave le ngt h. F ig . 3b : In te rsta ge m at ch i ng . Th e out pu t mat ch i s do ne by s er ie s t r an smi ss io n li ne TL 7 and s hun t ca pac it or C10. Aga in t hi s ca pac it or al so co mpen sa te s t h e in fl uen ce o f bi as s tu b TL6 . F ig . 3c: Ou tp ut ma tch in g . input Q1 TL1 output Q1 input Q2 TL2 TL3 TL4/TL6 TL5/C5 TL7 C10 output Q2

Philips Semiconductors B.V. Low cost DECT Power Amplifier PH97005 RNR-T45-97-M-0931 Bi asi ng Th e bi asi ng p ar t of t he P A is c ent er ed a rou nd a du al NP N t r ans is t or, Q3 a and b . Th e ci rc ui t of f er s a t e mper at ur e com pen sat ed b ia s vol t age f or b ot h t h e f i r st a nd the se con d RF st ag es. Unl i ke t he pr ev io us de mo bo ard P H960 60, th e ci rc ui t is act i va ted w hen Vc is h ig h, wh ic h is be yon d 2. 4 V. T he bi as o ut put v ol t age for t he f i rs t st ag e is a l i tt l e hi gher t h an for t he s eco nd st ag e. D ue t o s er ie s re si st or R 1, t he fis t sta ge is cur re nt d ri ve n and o per at es i n cl as s A. T h e se con d st age i s d ri ven b y at t he k nee v ol t age (0. 7 V) an d ope ra te s in c la ss AB . Se ri es r esi s to r R2 pr ot ec ts Q 2 fr om t h er mal r un away . Th e cur re nt de si gn of the P A d oes n’ t incl ud e any me asu res t o re duc e adj ac ent c han nel po wer d ue to s w it ch in g t r ans ie nt s. Th e sl ope o f th e RF pu ls e can be t oo s te ep an d h as to be r el axe d to c ompl y t o t he a ppr ova l sp eci f ic ati on . Th is c an be d one b y p la ci ng a ca pac it or at the b a s e o f Q3 a . Ex pe r ime nt al i nv est ig at io n has s hown t hat a 10 nF c apa ci tor ap pro xi mat el y o f fer s a 20 d B i mpr ove ment of t he ad ja cen t ch ann el po wer . Rec ommen dat i ons f or u s e Fi gu re 4 s hows h ow the PA sh oul d be c onn ect ed . F ig u re 4 :S ch e ma tic vie w of th e PA co n ne cti on s. I n pul se d con di ti on a t no min al s upp ly v ol ta ge an d out pu t po wer l ev el , the load c an be mi sma tc hed ( VSWR £ 6 : 1, al l ph ase s) wi t hou t da mage . Th e PA ca n a ls o be op er at ed in CW , bu t on ly w hen the ou tp ut i s pr op er ly ma tc hed wi t h 50 W . W he n a mis mat che d lo ad is app li ed w hen the am pli f ie r is ope ra te d in CW, th i s wi l l ca us e da mage o f the fin al s ta ge. C8 C9 C10 C11 C12 C13 R4R5 TL1 TL2 TL3 TL4 TL5 TL6 TL7 TL8 RF in RF out GND 3.6V supplypulse (active high)

Philips Semiconductors B.V. Low cost DECT Power Amplifier PH97005 RNR-T45-97-M-0931 BOAR D L AYOUT Fi gu re 5 s hows t he l ay out of t he P CB, wh ic h has th e fo l l owi ng p rop er ti es : t ype : FR 4 b il ay er ( ba cks i de gr oun d) h = 0. 71 mm t = 3 5 mm ( Cu c la ddi ng , no t co at ed) er = 4. 6 t and = 0. 02 F ig u re 5 :L ayo u t o f th e DE CT P A d e mo b oa rd . Al l r es is to rs a nd ca pac it or s us ed ar e Phi l ip s 060 3 SMD t y pe s. Ap pen di x A con ta in s t h e par t l i st of t h e demo b oar d. T he po si ti on o f co mpo nen ts C2 , C3 , C5 an d C10 is cr it i cal . Th e ar two rk f i le i s av ai la bl e on flo ppy d is c (DX F f o rma t) . C8 C9 C10 C11 C12 C13 R4R5 TL1 TL2 TL3 TL4 TL5 TL6 TL7 TL8

Philips Semiconductors B.V. Low cost DECT Power Amplifier PH97005 RNR-T45-97-M-0931 APP ENDI X Pa rt l i st D EC T PA de m o bo ard P H 970 05 Res i st or s R1 56 0 R2 56 R3 10 R4 22 0 R5 82 R6 33 0 R7 1 K Tr an smi ss ion l i nes TL 1 L = 6. 5 mm W = 0 . 45 mm TL 2 L = 3. 0 mm W = 0 . 15 mm TL 3 L = 7. 5 mm W = 0 . 15 mm TL 4 L = 2. 0 mm W = 1 . 15 mm TL 5 L = 7. 5 mm W = 0 . 15 mm TL 6 L = 2. 0 mm W = 1 . 15 mm TL 7 L = 5. 0 mm W = 0 . 45 mm TL 8 L = 6. 5 mm W = 0 . 15 mm Cap ac it or s C1 8. 2p C2 1. 8p C3 1. 8p C4 8. 2p C5 3. 3p C6 8. 2p C7 10 n C8 8. 2p C9 1n C10 2. 7p C11 8. 2p C12 8. 2p C13 1n Tr an si st or s Q1 BF G425 W Q2 BF G21W Q3 PUMX 1