Design Techniques for Microwave and Millimeter Wave CMOS Broadband Amplifiers

Transcription

1 ein Technique for Microwave an Millimeter Wave MOS Broaban Ampliier x ein Technique for Microwave an Millimeter Wave MOS Broaban Amplifier Shawn S. H. Hu an Jun-e Jin ept. of Electrical Enineerin, National Tin Hua Univerity Taiwan. Introuction The microwave an millimeter wave broaban amplifier i one of the key circuit block for hih-pee optical communication ytem. It i alo of extreme importance for wieban wirele communication operatin within microwave frequency rane. Previouly reporte reult were motly eine uin compoun emiconuctor III V (Maji-Ahy et al., 99; Maua et al., 3; Shiematu et al., ) or SiGe (Mullrich et al., 998; Weiner et al., 3) technoloie to take avantae of the uperior tranitor characteritic. ately, MOS technoloy with continuouly cale feature ize attract much attention of circuit einer for wieban amplifier application owin to the impreive cut-off an maximum ocillation frequencie (han et al., 8). onierin the requirement of moern interate circuit ein uch a low cot, low power conumption, an hih interation level with other circuit block, MOS technoloy i of reat potential for microwave an millimeter wave broaban amplifier application. Thi chapter provie the funamental ein concept of broaban amplifier uin the moern MOS technoloy. Variou ein technique are introuce for achievin hih performance microwave broaban amplifier. The main ein conieration an current tren are alo icue. We will ive a brief overview about the application of broaban amplifier an backroun information in ection. Section icue the conieration of tranitor an inuctive component in tanar MOS proce for broaban amplifier ein. Section 3 review ifferent ein technique for broaban amplifier with an emphai on the inuctor peakin technique. The banwith enhancement ratio (BWE) of each approach i calculate. In ection 4, recent avance on MOS broaban amplifier ein for microwave application are reporte. We propoe a pi-type inuctive peakin (PIP) technique to realize a 4 Gb/ tranimpeance amplifier (TIA) in.8-m MOS technoloy (Jin & Hu, 8). We alo propoe an aymmetrical tranformer peakin (ATP) technique to achieve a miniaturize 7 GHz broaban amplifier in.3-m MOS technoloy (Jin & Hu, 8). The core area i only ~.5 mm an the Gain-Banwith Prouct (GBP) i up to 3 GHz which i amon the hihet compare with other reporte work with imilar or even more avance technoloie. Finally, ection 5 provie the cloin remark of thi chapter an alo ome recommenation of further tuy on MOS broaban amplifier for microwave an millimeter wave application.

2 346 Microwave an Millimeter Wave Technoloie: Moern UWB antenna an equipment. Application of microwave an millimetre wave broaban amplifier The block iaram of a typical fiber-optic communication ytem i hown in Fi. (a). In the tranmitter ie, the laer river () amplifie the inal to moulate the laer ioe for convertin the electrical inal to optical inal. In the receivin en, a photo etector convert the weak optical inal that tranmit throuh the fiber back to the electrical inal, followe by a tranimpeance amplifier (TIA) an limitin amplifier (A) to amplify the photo current. Amon the front-en circuit block in a fiber-optic communication ytem, the, TIA, an A are all broaban amplifier. urrently, the ata rate of the ytem increae from -Gb/ (O-9) to 4-Gb/ (O-768) or even up to 8-Gb/ (O-536), an the eman increae a well for thee amplifier with a banwith up to microwave an millimeter frequency rane. Another main application of broaban amplifier i for wirele communication. The concept of broaban communication i to tranmit the ata in a certain banwith uch that the ata rate can increae an the emitte power can reuce. The wier the banwith, the reater the information-carryin capacity. There are ome pecific ban for the broaban communication uch a multichannel multipoint itribution ervice (MMS, - 3 GHz), worlwie interoperability for microwave acce (WiMax, - GHz), ultra-wie ban (UWB, GHz an GHz), an raio atronomy (9 KHz-75 GHz). A typical block iaram of a wirele communication ytem i hown in Fi. (b). For broaban application, the two front-en amplifier incluin the low noie amplifier (NA) an the power amplifier (PA) both have a wieban frequency repone. Fiber TIA aer river imiter etimer Antenna (a) (b) Fi.. (a) Block iaram of a typical fiber-optic communication ytem (b) block iaram of a typical wirele communication ytem. Switch PA NA VO Mixer Mixer. ein conieration for MOS broaban amplifier. MOS tranitor Tranitor play an extremely critical role in microwave circuit ein, ince the circuit conit of only a few tranitor in mot cae. Fiure how the mall-inal moel of a MOSFET, where i the poly ate reitance an i ue to the junction reitance. The four terminal are ate (G), rain (), ource (S), an boy (B). The ate-ource capacitance an ate-rain capacitance are important to the hih frequency repone of the tranitor. The capacitance b an b repreent the paracitic capacitance of the boy noe to the ource an rian terminal, repectively. G S + v m v mb v b r o b Fi.. Equivalent circuit moel of a MOS tranitor. b B

3 ein Technique for Microwave an Millimeter Wave MOS Broaban Ampliier 347 By nelectin the ource paraitic reitance an the econ orer effect from the boy noe, the unity current ain cut-off frequency f T an maximum ocillation frequency f max of a tranitor can be expree a: m ft () ( ) f max ( )( f T f T ) () where m i the tranconuctance an i the output conuctance (/r ). Accorin to the equation, the reitive an capacitive paraitic are the main limitation of the tranitor f T an f max, which can be minimize throuh the tranitor layout an election of tranitor eometry. In eneral, the ate reitance can be reuce by employin the tranitor with a multi-finer topoloy an a hort with of each finer. The ate with W of each finer typically ue i in a rane of to 3 m for F ein if f max i the major ein conieration. A lare finer number n can increae the tranconuctance for hih-ain amplifier ein, while f max reuce with the increae total ate with ue to the increae of paraitic. Note that f T i relatively le enitive to the increae finer number ince the increae of m compenate the aitional paraitic capacitance. Fiure 3 how the f T an f max of.3-m NMOS a function of W an n bae on the founry provie tranitor moel. A hown in the fiure, the tranitor of a loner W (5 m) have hiher f T compare to that of a horter W (. m) with the ame n, which can be attribute to the increae rate of m i hiher than that of the paraitic capacitance a W increae from. m to 5 m. It can alo be oberve that f T oe not increae inificantly with n. On the other han, the tranitor with a horter W preent hiher f max reultin from the lower ate reitance, maller output conuctance, an alo the lower (uner the ame n). A the total finer number increae, f max ecreae inificantly mainly ue to the increae paraitic capacitance an output conuctance. Frequency (GHz) fmax ft V =.65 V, V =.3 V W =. m W = 5m Finer number Fi. 3. Tranitor (.3-m NMOS) f T an f max a function of the finer with W an finer number n. (W =. m an 5 m ) The paraitic can alo be reuce by the interconnect layout in the tranitor. The wirin effect coul be inificant on the correponin paraitic capacitance an reitance

4 348 Microwave an Millimeter Wave Technoloie: Moern UWB antenna an equipment epecially for avance technoloy with a mall feature ize (han et al., 8). For tranitor with a mall ate lenth uch a 65 nm, the paraitic oriinate from the tranitor interconnect are critical to the overall frequency repone. By chanin the ource, rain an ate interconnect in the tranitor, the capacitive an reitive paraitic can be reuce effectively leain to improve cut-off frequency f T an maximum ocillation frequency f max. For example, we propoe uin the rin-type ate tructure an the reuce number of interconnect layer in 65 nm N-MOSFET. The f T an f max are improve up to % an % repectively without chanin any proce tep. Fiure 4 how the comparion of the typical layout uin the meaner-type ate with four interconnect metal layer (M ~ M 4 ) from the founry an the propoe tranitor layout with the rin-type ate an only two interconnect layer (M ~ M ). The correponin cro ection are alo preente a inicate in the fiure (A-A, B-B, an - ). A can be een, the minimize metal interconnect layer can inificantly reuce the iewall paraitic capacitance an the via inuce paraitic reitance leain to improve f T an f max. The improve tranitor characteritic are beneficial to broaban amplifier performance. Via (a) Via (b) Fi. 4. Tranitor layout an the correponin cor ection (a) typical foury provie layout (b) propoe layout approach. The iewall paraitic capacitance an the via inuce paraitic reitance are both reuce in (b).. Inuctive component ompare with the low frequency amplifer uin analo circuit ein approache, one major ifference for microwave amplifier i the ue of inuctive paive component. In eneral, the inuctive component are utilize for the matchin network in microwave circuit. In aition, with inuctive component, the paraitic capacitance which limit the hih pee operation of a MOSFET can be reonate out to achieve wieban characteritic. For MOS I ein, the inuctive component uch a inuctor an tranformer are uually eine a a piral hape to maximize the inuctance while minimize the chip area. ein of piral inuctor mainly conier the with w of the line, pacin between the line, an the metal thickne t. The founry often provie a thick top metal layer for hih Q inuctor ein, which ha a rane aroun m to 3 m. The pacin i limite by the technoloy, an the minimum value i uually employe for hih inuctance an mall chip area. The minimum with of the metal line i alo limite by the technoloy. The conume

5 ein Technique for Microwave an Millimeter Wave MOS Broaban Ampliier 349 chip area reuce if uin a mall w, wherea the paraitic reitance coul increae an the inuctor quality factor (Q factor) coul rop. For a wier line, a hiher Q factor may be achieve, but the paraitic capacitance coul limit the operation frequency. Fiure 5 compare the quare an octaonal inuctor for the inuctance an Q bae on EM imulation. With the ame chip area ( m m), the octaonal ein ha a lihtly maller overall lenth an thu a maller inuctance. The octaonal ein alo ha le reitive paraitic reultin in a hiher Q. Note that the quare type inuctor i more uitable for wieban application ownin to it lower Q an therefore a wier banwith for reonance. Inuctance (nh) Square Octaonal Frequency (GHz) Fi. 5. omparion of piral inuctor with two iffent hap. (w= 4 m, = m, t=.3 m, inner iameter= 4 m) On-chip tranformer are alo wiely ue for microwave an millimeter wave amplifier ein. Tranformer provie flexible matchin an inuctive peakin capability with variable couplin ratio an alterable polarity. In ome cae, a tranformer i eentially equivalent to two inuctor with aitional mutual inuctance but conume an area imilr to one inuctor. The tranformer layout i alo imilar to a ymmetrical piral inuctor with a turn ratio cloe to one. Fiure 6 how ifferent layout of tranformer for mall turn ratio ein. The black line repreent the primary coil an rey line repreent the econary coil. The layout of type (a) ha a mall couplin factor becaue of le mutual inuctance, an i relatively imple to achieve the eire couplin factor. The ein of type (b) ha a moerate couplin factor. Type (c) ha a lare couplin factor while the quality factor i maller ue to the capaitive paraitic. Note that the econary ie conit of everal coil connecte in parallel to obtain a mall turn ratio. For thee tranformer with the winin in the ame metal layer, the maximum achieveable coupln factor mainly epen on the minimum metal pacin. Another ein hown in Fi. 6() ue two ajacent metal layer for the winin of the coil. A hih couplin factor can be achieve if a thin ielectric layer i between the two metal can be ue. Note that the paraitic capacitance i relatively lare, which coul limit the operation frequency. A eneral repentation of the equivalent circuit moel for an on-chip tranformer i hown in Fi. 6(e), where an repreent the ohmic loe ue to the reitivity of the inuctor metal line; p i the paraitic capacitance of each coil oriinate from the pial routin; m repreent the couplin capacitance between the primary an econary coil; ox i the oxie layer paraitic capacitance an i an i repreent the couplin an ohmic loe ue to the ilicon ubtrate. The coefficient M ecribe the inuctive couplin between the primary an the ecoary coil Q

6 35 Microwave an Millimeter Wave Technoloie: Moern UWB antenna an equipment (a) (b) (c) () (e) Fi. 6. (a)-() ifferent ein of tranformer (e) equivalent circuit moel of an on-chip tranformer. It i worth mentionin that co-ein of active an paive component i a ueful approach to optimize the performnce of microwave circuit. For the operation frequencie up to ten of GHz, the uneire reitive an capacitive component can eriouly erae the amplifier performance. A mentione earlier, interconnect in a tranitor i a critical iue for it frequency repone an the inuctive component are ueful for banwith enhancement. By co-ein of the tranitor interconnect an the inuctive component, the paraitic can be effectively minimize to enhance circuit performance. More etail will be icue later uin the propoe broaban amplifier a an example, in which the tranformer ein conier with the tranitor interconnect layout imultaneouly to reuce the paraitic. 3. ein Technique for Broaban Amplifier For the broaban amplifier eine by MOSFET, the circuit banwith i ultimately limite by the intrinic capacitance of the tranitor. ifferent approache were propoe for banwith extenion uch a f T oubler (Galal & azavi, 3), neative impeance converter (Galal & azavi, 3), neative Miller capacitance (Galal & azavi, 3; Mataya et al., 968), itribute amplifier (A) (Arbabian & Nikneja, 8; hien & u, 7), an inuctive peakin technique (Mohan et al., ; Galal & azavi, 3; Galal & azavi, 4), a hown in Fi. 7. The main ein concept in thee technique i all relate to how to reuce the impact of the paraitic capacitance on the circuit. ompare with the conventional ifferential amplifier, the f T oubler topoloy reuce the input capacitance rouhly to half an thu the f T exten out to twice of the frequency. The neative impeance converter can enerate neative impeance to cancel the uneire paraitic for

7 ein Technique for Microwave an Millimeter Wave MOS Broaban Ampliier 35 banwith enhancement. The neative Miller capacitance technique ue the imilar concept to cancel the ate-rain capacitance of the tranitor to exten the banwith. ompare with the banwith enhancement uin paive component, thee technique utilize active component with a maller chip area while conume aitional power. Note that the effectivene of the banwith extenion i enitive to the bia conition an coul inuce uneire ocillation problem. V out- V out+ V in+ V in- M M M 3 V out- V out+ M4 M M M 3 M 4 I SS I SS I SS c ISS V in+ M M V in- I SS (a) (b) (c) / Input / M m v + v m v + v m v n + v n / MG / Output + v m v () Fi. 7. Banwith enhancement technique: (a) f T oubler (b) neative impeance converter (c) neative Miller capacitance () itribute amplifier (A), an (e) inuctive peakin. The A confiuration i a popular technique an Fi. 7() how the implifie circuit cheme for a MOS itribute amplifier. The reitor MG an M terminate the ate an rain line to minimize the etructive reflection for tability an ain flatne. With the inuctor an, the input an output artificial tranmiion line are contructe by incorporatin the equivalent ate an rain capacitance an, repectively. By a proper ein of the tranmiion line elay, the output inal from each tae i ae in phae reultin in a ain-banwith prouct much reater than that of an iniviual amplifier. It houl be mention that the A architecture normally conume a lare power an occupie a conierable amount of chip area for obtainin a hih ainbanwith prouct. Another attractive ein approach i the inuctive peakin technique. The funamental iea i to introuce a zero by an inuctor to cancel the oriinal pole an exten the circuit banwith. Fiure 7(e) how a imple example of the inuctive peakin topoloy, which i a common-ource (S) amplifier with hunt inuctor peakin. With a peakin inuctor connecte in erie with the loa reitor, the capacitive paraitic can be (e)

8 35 Microwave an Millimeter Wave Technoloie: Moern UWB antenna an equipment reonate out at the frequency aroun the oriinal pole to exten the circuit banwith. The inuctive peakin technique can achieve a lare banwith while maintain a mall power conumption. Variou inuctor peakin confiuration uch a hunt peakin, hunt-erie peakin (Fi. 8(a)), an T-coil peakin technique (Fi. 8(b)) will be analyze toether with the icuion of the banwith enhancement ratio (BWE) of each technique. Note that the comparion i bae on a funamental cacae common-ource topoloy, which i wiely ue for hih frequency broaban amplifier. The propoe wieban ein technique a will be illutrate in Section 4 alo employ the cacae confiuration. One funamental ifference between the A an the cacae topoloy i the overall ain of each tae for the former um up wherea that for the latter multiplie. A a reult, the power conumption an chip area can be effectively reuce uin the cacae confiuration. m v v out m v p v out k B (a) Fi. 8. (a) hunt-erie inuctive peakin (b) T-coil inuctive peakin. (b) 3. Shunt Peakin For the mall-inal equivalent circuit moel of a cacae S amplifier, a hown in Fi. 9, the 3-B banwith of each tae i etermine by the rain reitance, equivalent rain capacitance, an equivalent ate capacitance of the next tae. The ratio of to can be etermine from the founry provie moel for a more practical etimation, which i between.5 an 3.5 (.5 ~ 6 GHz) in.8-m MOS technoloy. Note that the ate-to-rain capacitance i plit by the Miller theorem an inclue in an in thi cae. To implify the circuit analyi, / i et to be 3 for the followin analyi. + v m v + v Fi. 9. Small-inal equivalent circuit moel of a cacae common-ource amplifier. The mot traihtforwar banwith enhancement technique i probably hunt peakin (Mohan et al., ), a hown in Fi. 7(e). By connectin an inuctor in erie with, the paraitic capacitance of the rain noe can be reonate out by a hunt reonance. An

9 ein Technique for Microwave an Millimeter Wave MOS Broaban Ampliier 353 alternative explanation i that the peakin inuctor introuce a zero to exten the circuit banwith. Bae on the tranimpeance tranfer function, the ein equation for can be erive an written a: m (3) With an m of.7, the maximum achievable BWE i.85 with a ain peakin of.5 B, a hown in Fi., curve (ii). Note that curve (i) i the normalize frequency repone of thi circuit without any banwith enhancement metho applie. 3. Shunt-erie Peakin The econ technique i hunt-erie peakin (ee Fi. 8(a)) which employ two inuctor, one inuctor i connecte in erie with an the other inuctor i in erie with. The ein equation for both inuctor can be written a: (4) 4 The circuit analyi preente in the oriinal publication (Galal & azavi, 4) how a BWE up to 3.46 with a ain peakin of.8 B bae on the aumption that / i one. However, the BWE reuce to.83 when / of 3 i ue, a hown in Fi., curve (iii). 3.3 T-oil Peakin A more effective technique i the T-coil peakin (Galal & azavi, 3) which utilize one tranformer an one capacitor a hown in Fi. 8(b). The primary coil p i connecte between the rain noe an, an the econary coil i between an. In aition, the brie capacitor B i connecte between the rain noe an. By nelectin, the ein equation for the tranformer an capacitor can be written a: 4 4 p (5) 4 k (6) 4 B (7) 6 For a flat roup elay repone, a of 3/ reult in a BWE of.8 if i nelecte. Note that the BWE obtaine in Fi., curve (iv) i reuce to.4 ince i taken into account for a fair comparion.

10 354 Microwave an Millimeter Wave Technoloie: Moern UWB antenna an equipment Normalize ain (B) i: without any peakin technique ii: hunt peakin iii: hunt-erie peakin iv: T-coil peakin Normalize frequency (ra/) Fi.. Frequency repone of uin ifferent inuctive peakin technique for banwith improvement. 4. Propoe Broaban ein Technique The above icue banwith enhancement technique are effective an have been ue in many MOS broaban amplifier. In thi ection, we introuce two ifferent inuctive peakin technique for wieban amplifier ein. 4. π-type Inuctor Peakin (PIP) Fiure. how the mall-inal equivalent circuit moel of a cacae S tae incluin the propoe PIP inuctor (,, an ), where an are the rain bia reitor. An improve BWE up to 3.3 can be obtaine uin the PIP inuctor peakin technique by incluin the rain capacitance, an uner an aumption that the ratio of / i 3. The banwith improvement by ain each peakin inuctor i ecribe a follow. v out m v Fi.. The equivalent circuit moel of one ain tae with the pi type inuctor peakin (PIP) technique.

11 ein Technique for Microwave an Millimeter Wave MOS Broaban Ampliier 355 If not conierin the inuctor, the rain current m v flow into,,, an, an enerate the output voltae v out. In thi cae, the 3-B banwith ω i limite by the reitive an capacitive loa. By inertin in erie with, the banwith i increae by a parallel reonance with an. If i alo ae, the banwith can be further enhance by a erie reonance with at hiher frequencie, which force more rain current to flow throuh an reach the output terminal. Finally, by introucin one more inuctor, an can be reonate in parallel with at even hiher frequencie to obtain a further improve banwith. Accorin to the circuit hown in Fi., Fi. i the frequency repone of the above four conition, where ω an the ain are both normalize. The raually improve banwith can be oberve a ain the three peakin inuctor tep by tep. An improve BWE up to 3.3 can be obtaine with the three PIP inuctor Normalize ain (B) Normalize frequency (ra/) i: without any inuctor ii: iii: + iv: + + Fi.. omparion of the banwith enhancement reult uin PIP technique uner ifferent number of peakin inuctor, where = 3 an =. Bae on the circuit in Fi., the tranimpeance tranfer function Z PIP () can be erive a follow: v v Z m out PIP (8) where (9)

12 356 Microwave an Millimeter Wave Technoloie: Moern UWB antenna an equipment The require inuctance for banwith improvement can be etermine analytically from the tranfer function. The numerator inclue two zero ( / ) an ( / ) an the enominator contain two pair of complex conjuate pole. By olvin the tranfer function with properly eine ampin factor (<.77), thee zero an pole can enhance the banwith effectively. The propertie of the pole an zero a ain the three peakin inuctor tep by tep are ummarize in Table. Note that thee value are obtaine by aumin the ain flatne i maller than. B. without PIP Zero Pole omplex pole ampin factor p. z.33, p.5, p, p.79 z.33, p., p3.37, p, p3, p, p z.5 z, p3, p.8, p4 3., p, p4.39, p, p Table. Propertie of the pole an zero of one ain tae with PIP uner ifferent number of peakin inuctor, where an ω n are the ampin factor an the corner frequency of the complex pole, repectively. Bae on the propoe PIP technique, a tranimpeance amplifier taretin at 4-Gb/ for O-768 application i realize in tanar.8-μm MOS technoloy. The 4-Gb/ TIA compoe of four cacae S tae for hih tranimpeance ain, a hown in Fi. 3. Ientical reitance for the rain bia reitor of each tae i employe, an the input an output impeance are eine a 5 Ω throuh the reitor M ~ M4. For a hihain conieration, a lare i preferre while the require peakin inuctance for PIP topoloy increae a well. A trae-off exit here ince a lare inuctor not only occupie more chip area but alo ha lower operation frequency. The reitive paraitic aociate with a lare inuctor alo erae the circuit performance. In practical ein, i ~ ohm an the inuctor are eine to be maller than the calculate value to reuce the reitive lo. V M3 M4 M M P4 P5 P4 P5 P4 P5 P7 P8 P P P6 P6 P6 P9 V out I in P3 M M M 3 M 4 Fi. 3. ircuit topoloy of the propoe 4-Gb/ MOS TIA with PIP.

13 ein Technique for Microwave an Millimeter Wave MOS Broaban Ampliier 357 Fiure 4 compare the ein of a TIA with an without uin the propoe PIP technique. With a tranimpeance ain Z T of 5 BΩ, the imulate banwith for the TIA with PIP i improve by a factor up to ~ (33.8 GHz/3. GHz) compare to that without applyin the PIP inuctor. 6 5 Z T (B) 4 3 TIA without PIP TIA with PIP Frequency (GHz) Fi. 4. Simulate frequency repone for the TIA with an without PIP. The TIA wa fabricate in.8-μm MOS technoloy with a chip area of.7.46 mm an meaure on-wafer with coplanar roun-inal-roun (GSG) probe. The meaure tranimpeance ain Z T i hown in Fi. 5 (a). The ain an the 3-B banwith are 5 BΩ an 3.5 GHz in the preence of an on-chip p of 5 ff at the input, repectively. Note that the p place at the input i to take the photoioe paraitic capacitance into conieration. Uner a.8 V upply voltae, the amplifier conume 6. mw, an a ain-banwith prouct per power fiure-of-merit (GBP/P c ) of 8. GHzΩ/mW i achieve. To meaure the tranient repone of the 4-Gb/ TIA, a hih pee 3 - PBS i applie. With an input current win of 74 μa pp, the output eye iaram at 4-Gb/ i hown in Fi. 5 (b) with an output voltae win of 63 mv pp. Z T (B) Z IN () 6 mv/iv Frequency (GHz) p/iv (a) (b) Fi. 5 Meaure (a) tranimpeance ain Z T an (b) eye iaram at 4 Gb/ ( 3 - PBS) of the amplifier uin PIP technique.

14 358 Microwave an Millimeter Wave Technoloie: Moern UWB antenna an equipment 4. Aymmetrical Tranformer Peakin (ATP) Tranformer are very ueful for enhancin the microwave circuit performance owin to the mutual inuctance. Amplifier eine with tranformer alo allow operation uner a low upply voltae. ompare to the inuctor peakin technique, peakin with tranformer can exten the banwith wherea with an improve area efficiency. Fiure 6 how the propoe aymmetrical tranformer peakin (ATP) technique for broaban amplifier ein. The baic ein i alo the cacae common-ource (S) confiuration to enhance the ain-banwith prouct. ompare with the typically ue cacoe topoloy a a unit ain block for microwave amplifier ein, the S ein i eaier for achievin low power ein ownin to the low upply voltae. Similar to other inuctor peakin technique, the baic iea of ATP i to reonate out the paraitic capacitance for banwith enhancement. Moreover, the tranformer ha the avantae of aitional mutual inuctor to reuce the require area of inuctor. The aymmetrical primary an econary coil can alo accommoate the unequale paraitic loain capacitance in a tranitor. Bae on the founry provie tranitor moel an ieal inuctive component, Fi. 7 how the comparion of three ein with the ame baic five-tae S confiuration. The reult inicate that thee ein preent a imilar low-frequency ain but with an obviou banwith ifference. Without applyin any peakin technique, the banwith i only 7. GHz (curve (i)), while the banwith can be inificantly enhance up to 69.7 GHz (curve (ii)) if the tranformer i ymmetrical. With the further improvement with aymmetrical coil in tranformer ein, the banwith increae up to aroun 8 GHz (curve (iii)). V M k S k S k S k S k S Input k S P M P M P M P M P M P Output Fi. 6. The propoe broaban amplifier uin aymmetrical tranformer peakin (ATP) technique. 8 5 i : Without any peakin technique ii : Symmetric tranformer peakin iii : Aymmetric tranformer peakin S (B) Frequency (GHz) Fi. 7. Simulate frequency repone with ifferent inuctive peakin technique.

15 ein Technique for Microwave an Millimeter Wave MOS Broaban Ampliier 359 The mall-inal equivalent circuit moel for one ain tae in the cacae S confiuration uin tranformer peakin technique i hown in Fi. 8, where i the ate capacitance of the next tae an k i the couplin factor. Bae on thi moel, the tranimpeance tranfer function Z T () from the current ource m v to the output voltae v out can be erive a: vout ZT mv () S k PS / 3 4 k k P S S A can be oberve from (), one zero (numerator) an two pair of complex pole (enominator) are introuce, an the ampin factor of the pole coul be maller than.77 if the circuit i properly eine. For the cae of P = S, the ein i not optimize ue to the inherently unequale loain capacitance ( ) from each ie of the tranformer. P S P P S P v out k m v S Fi. 8. Small-inal equivalent circuit moel for one ain tae uin tranformer peakin technique. The polarity of the tranformer i alo critical in thi ein. With a imilar confiuration but oppoite tranformer polarity, the erive Z T from () can be applie irectly except that all the in nee to be invere for the k-relate term. In other wor, the couplin coefficient k become neative in the oriinal equation. Thi ifference reuce the frequencie of the zero an the complex pole reultin in a maller BWE. Bae on the above analyi, the unequal inuctance an an appropriate tranformer polarity are both beneficial for banwith extenion. By uin the aymmetric tranformer T, the circuit banwith can be enhance up to 8.6 GHz with a ain flatne of ±. B by P =. nh, S =. nh, an k=.3, a hown in Fi. 7, curve (iii). It houl be mention that a co-ein appraoch i aopte to minimize the uneire paraitic an further enhance the amplifier performance. For millimeter wave ein, layout i critical for circuit performance. In thi tuy, the tranformer layout i co-eine with the tranitor for reucin the lo from interconnect paraitic an minimizin the chip area. In the aopte.3-m MOS technoloy, one-poly an eiht-metal layer (P8M) with variou metal thicknee an line pacin are available for tranformer ein. In typical ein, the top layer M8 i employe for inuctive component owin to the thicker metal for a lower conuctor lo. However, if conierin the interconnect an the overall circuit performance, M3 i a better choice for the tranformer winin. By uin M3 intea of M8, the aitional lo introuce by the metal/via connection from M3 to M8 can be

16 36 Microwave an Millimeter Wave Technoloie: Moern UWB antenna an equipment eliminate, which can be inificant at the frequency of interet. In aition, the minimum metal pacin of M8 i retricte to m, wherea the M3 layer provie a pacin of. m enablin a tranformer with an enhance couplin coefficient. Althouh the thickne of M3 i maller than M8, the kin effect a operatin at ten of GHz make the metal thickne not that critical. For achievin the eire inuctance ratio while maintainin ein implicity, two iniviually woun inuctor are cloely place to form a tranformer, a hown in Fi. 9 (a). Fiure 9 (b) i the chip microraph of the five-tae S broaban amplifier with aymmetrical tranformer peakin. The circuit area incluin the an F probin pa i mm, an the core area i only.48. mm (~.5 mm ). (a) Fi. 9. (a) On-chip aymmetric tranformer layout (b) chip microraph (area: mm, core area:.48. mm ) The broaban amplifier wa fabricate in a tanar P8M.3-μm MOS proce. The roun-inal-roun (GSG) F probe were ue for the on-wafer S-parameter meaurement from GHz to GHz, a hown in Fi. toether with the imulate reult. The meaure S at low frequencie i.3 B an the circuit banwith i 7.6 GHz uner a power conumption P of 79.5 mw. A ain-banwith prouct of 3 GHz an a GBP/P of.9 GHz/mW are achieve. The meaure revere iolation S i well below -3 B up to GHz. In aition, the meaure S an S are below -6. B an -.8 B repectively within the circuit banwith. The meaure output -B compreion point P B,out are. Bm, -. Bm, an -. Bm at 5 GHz, GHz, an GHz, repectively. (b) Manitue of S (B) Soli line: Simulation Symbol: Meaurement Phae of S (eree) Manitue of S (B) Phae of S (eree) Frequency (GHz) (a) Frequency (GHz) (b)

17 ein Technique for Microwave an Millimeter Wave MOS Broaban Ampliier Manitue of S (B) Phae of S (eree) Manitue of S (B) Phae of S (eree) Frequency (GHz) Frequency (GHz) (c) () Fi.. Meaure an imulate S-parameter of the propoe broaban amplifier uin the propoe aymmetric tranformer peakin (ATP). 5. oncluion In thi chapter, variou apect for the ein of microwave an millimeter wave broaban amplifier uin moern MOS technoloy were icue. Section briefly introuce the application of broaban amplifier in wireline/wirele communication ytem. Section illutrate the ein conieration of tranitor an inuctive component uin tanar MOS proce. The tranitor eometry an interconnect were hown to be critical to it hih frequency repone. The ein traeoff were alo analyze for piral inuctor an tranformer in MOS technoloy. In ection 3, ifferent ein technique for broaban amplifier were reviewe. Three inuctor peakin technique incluin hunt, hunt-erie, an T-coil approache were compare in etail. Section 4 focue on the banwith enhancement technique that we propoe for MOS broaban amplifier ein. With the propoe -type inuctive peakin (PIP) technique, a 4 Gb/ tranimpeance amplifier (TIA) wa realize in.8-m MOS technoloy. We alo propoe an aymmetrical tranformer peakin (ATP) technique to achieve a miniaturize 7 GHz broaban amplifier in.3-m MOS technoloy with a core area of only ~.5 mm. The PIP an ATP ein technique can be utilize for many hih-pee builin block in wireline/wirele communication ytem, uch a laer/moulator river, multiplexer/e-multiplexer, an low noie amplifier/power amplifier. The uccefully emontrate ein technique for enhancin the performance of MOS interate amplifier at microwave an millimeter wave frequencie enable further tuie for variou application. 6. eference Arbabian, A. & Nikneja, A. M. (8). A broaban itribute amplifier with internal feeback proviin 66GHz GBW in 9nm MOS. IEEE ISS i. Tech. Paper, pp , Feb. 8 han,. et al. (8). Wirin effect optimization in 65-nm low-power NMOS. IEEE Electron evice etter, 9,, (Nov. 8) pae number (45-48)

18 36 Microwave an Millimeter Wave Technoloie: Moern UWB antenna an equipment hien, J.-. & u,.-h. (7). 4Gb/ hih-ain itribute amplifier with cacae ain tae in.8μm MOS. IEEE ISS i. Tech. Paper, pp , Feb. 7 Galal, S. & azavi B. (3). -Gb/ limitin amplifier an laer/moulator river in.8- μm MOS technoloy. IEEE J. Soli-State ircuit, 38,, (ec. 3) pae number (38-46) Galal, S. & azavi B. (3). Broaban ES protection circuit in MOS technoloy. IEEE J. Soli-State ircuit, 38,, (ec. 3) pae number (334-34) Galal, S. & azavi B. (4). 4-Gb/ amplifier an ES protection circuit in.8-μm MOS technoloy. IEEE J. Soli-State ircuit, 39,, (ec. 4) pae number ( ) Jin, J.-. & Hu, S. S. H. (8). A 4-Gb/ tranimpeance amplifier in.8-μm MOS technoloy. IEEE J. Soli-State ircuit, 43, 6, (June 8) pae number ( ) Jin, J.-. & Hu, S. S. H. (8) A miniaturize 7-GHz broaban amplifier in.3-μm MOS technoloy. IEEE Tran. Microw. Theory Tech., 56,, (ec. 8) pae number (386-39) Majii-Ahy,. et al. (99). 5 GHz InP coplanar waveuie MMI itribute amplifier. IEEE Tran. Microw. Theory Tech., 38,, (ec. 99) pae number ( ) Maua, S. et al. (3). An over--ghz InPHEMT flip-chip itribute baeban amplifier with inverte microtrip line tructure for optical tranmiion ytem. IEEE J. Soli-State ircuit, 38, 9, (Sept. 3) pae number ( ) Mataya, J. A. Et al. (968). IF amplifier uin c compenate tranitor. IEEE J. Soli-State ircuit, S-3, 4, (ec. 968) pae number (4-47) Mohan, S. S. et al. (). Banwith extenion in MOS with optimize on-chip inuctor. IEEE J. Soli-State ircuit, 35, 3, (Mar. ) pae number ( ) Mullrich, J. et al. (998). 4Gbit/ tranimpeance amplifier in SiGe bipolar technoloy for the receiver in optical fibre TM link. Electron. ett., 34, 5, (Mar. 998) pae number (45 453) Shiematu, H. et al. (). A 49-GHz preamplifier with a tranimpeance ain of 5 BΩ uin InP HEMTS. IEEE J. Soli-State ircuit, 36, 9, (Sept. ) pae number (39 33) Weiner, J. S. et al. (3). SiGe ifferential tranimpeance amplifier with 5-GHz banwith. IEEE J. Soli-State ircuit, 38, 9, (Sept. 3) pae number (5 57)

19 Microwave an Millimeter Wave Technoloie Moern UWB antenna an equipment Eite by Ior Mini ISBN Har cover, 488 pae Publiher InTech Publihe online, March, Publihe in print eition March, How to reference In orer to correctly reference thi cholarly work, feel free to copy an pate the followin: Shawn S. H. Hu an Jun-e Jin (). ein Technique for Microwave an Millimeter Wave MOS Broaban Amplifier, Microwave an Millimeter Wave Technoloie Moern UWB antenna an equipment, Ior Mini (E.), ISBN: , InTech, Available from: InTech Europe Univerity ampu STeP i Slavka Krautzeka 83/A 5 ijeka, roatia Phone: +385 (5) Fax: +385 (5) InTech hina Unit 45, Office Block, Hotel Equatorial Shanhai No.65, Yan An oa (Wet), Shanhai, 4, hina Phone: Fax: