(gal OCR Output"First workshop on elcctn mics lor LH<` cxperirnents" Lrsbonne l l·l5 septembre l°)9F

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transistor technology

These results may contribute to prove the feasibility of l`ront—end electronics in bipolar

complementary bipolar process. Preliminary results ot some prototypes will be given.

(`hips have been made using rad-hard capability Harris Semiconductor UHF

lem-! area and 50pF capacitance. Performances and results will be presented.

noise lower than 2500 e- mis has been achieved in beam tests with PIN photodiodes of

with bipolar transistor devices for detector capacitances in the range of 10 to l()()pF. A

the CMS electronwgnctnc calommetcr. A fast low noise preamplifier has been designed

A from-end Lransinipcdamc prcamplmer is studied to be matched with photodetector in

ABS’1`RA<"|

43 Boil/mtlavl/tilt ll Nmwzz/m· IQMA h%22 V:/leurhanne cedex, France.

Insritul de P/zxxmym »\'nw/m11r‘¤* lie Lxwz, IN'2P#’—CNRS or lfniversiré Claude Bernard

M. (Lovot

_ _ _ of the LMS electromagnetic calorimeter.ream lifier in bi olar technolo for silicon hotodetectors P Y

Development of high speed low noise transimpedance

Octobrc 1995

LYCEN 9535Q[: ¢¢¢

resistance Rbb' = IOQ,with: collector current lc=().4mA, Beta = lltlt base spreadingENCD·i = k (2KT/RT + q(linv+lc/till c

ENC} = k.(2KT(Rbb'+Rs+l/2gm• + tjlcxt5.t”Rbb`lZJ.tCtl>2/rin the case of BJT,

l/fnoise: Af: l()'l4.gm=2(lmA/V, input capacitance (`in : Cgs+Cgd=20pF.

with; leakage current lL:5ttpA. transconductance

ENC yi = 2l<..Af.(Cin+Cd)

ENC pi = k t2KT/RT + q.(lL+limt> i input transistor. OCR Output

been selected with a collector current of about 390uA for theENC Se = kt2KT<Rs+().7/gm).(Cin+t `illpossibilities, The traditional grounded emitter topology hasin the case of JFET,between simplicity, consumption and extemal controlcalculations:The detailed circuit diagram in figure 4 is a compromiseThe following expressionsare used lor ENC[7·R]

hgure 3preamplifier is followed by a RC-CR filter amplifier.0.2pF

amplifier having a low feedback resistance value. The t¤F * MAFjunction field effect transistor (JFT€Tl followed by an ideal l agi: i *; l¤·#' » -{|— *~~W··’\/\/\/*·r···j ,The input device is a bipolar junction transistor (BIT; or a

FE M., .,bupj¤(§,_O mite I [q5*/Slk `\

The test capacitance is integrated on the circuit.figure buffer to drive 509 line.

integration cell = 5ns.front-end with RF (gain) and Cf (phase control).

39K<lr=tvcto·` m The circuit is composed of;

· A preamplifier simplified schematic is shown in figure 3.imtlltxzz

. T A PREAMPLIFIER DES IGN"i`“""’“

ltluns 3figure 2

BIT ——¢——— FET Q BJT ——-A--— FETcurrent sensitive conliguration shown in twurc

The equivalent noise charge has btw: out ulatetl lor the shaping fime (ns}

tl 2tl 40 60 80 100NOISE l€VAt.L¢\ l lr iwltttto +____._ ,`T

PbW()4 crystals.l it lit -q

obtained in tests beam are giwii tor ~\Pl>l— associated tol0nA

response and noise have been ineasured Some results ltltltl

configuration is proposed. Experirncntal results. transienthigh quality UHF devices. A transinipedance preamplifier "’g.¤:i°'..»·&' 2=oo . ...g --r...Pi--.i..of a lront—cnd with a good perforinzuicc is easier by the use ol ,sooo e .... . - .,':>\ /K ~/A ...... . Lbroadband and lovt noise preampltlicrs . Now, thc design _ r-·O°.' ,#'-6I *0]

»_,..0 ,Several publications proposed to use bipolar transistors in win r»·" #v-4» *-1 » gshaping time and relatively large photodetector capacitances. l(lj,ii;.__'_.-·O' /A

-*-1,-sltltltlbipolar junction transistor is a good teclmology for short

shaping is the best solution to soltc these problems and thetlitltl

processing time range typically trom ttl to Xtlns. A last

the variation ot` this parameter. The working conditions torsee in figure 2.clmracterislics of associated from-end must not change with

increases up to 10 nA or more due io rzadmtioii ellecl. The equivalent for bipolar and the field—effect transistor as we can

in initizil lgonditioiis. Lhc silicon nlctcclor lczikziuc currcnl For a 2()ns RC—CR shaping time the noise charge is practicallyrcccully Al’D’s which will bc probably uxcil Froin l or l() nA k = shaping factor, r=RC.nrc silicon solid suite dcviccs 3 PlN pliotodiodcs und more input parrallel resistance RT = 33K$2.

Thu plxuwscxxsnrs which are smdmg tm xhu CE\1S-EVAL serial resistance Rs = 59.

Detector: capacitance Cd = 50pF, linv = 10nA and 10ttA,and with the following parameters values;

1.3 x l.9mm

The chip layout is shown in figure o. lts area is equal to charge is not completly integrated inside the gate (eq.2). OCR Outputtesting must be used. capacitance above 50pF, the slope increases because the totalln order to limit these parasitic serial induetanee a direct die slope is constant. With a short gate tl60ns) and an inputwith pnp at the input is stable at nominal collector current. When the integration time increases. the curve shifts but theparasitic serial inductance. In these conditions. only the circuit gate = l6()ns: (ENCV = (17.1 Ciri)+ (I922)(2)2 2very easy to use but the wire bonding length introduces a gate = 250ns; (ENC)f = (16.0 Cin); + (2477)* (1)first test, the dies are mounted in dual in line package lt is function of input capacitance

Two complementary ASIC's have been processed. For the different gate values. The results are shown in figure 8 as aand calculation agree very well. The noise measurement in gated integrator mode is made for(l2.5ns/div), figure 5b. As we can see, experimental results input.(20ns/div) in comparaison with a typical measured response time: 5ns in the front—end and l0ns at the post-amplifierFigure 5a shows an example of simulatetl transient response integrations are used to match the detector signal processing

ligure 5 A discrete semiconductor version has been tested. Two

L;j,~•'DA _ __A__ irir l: Mudd ·‘` SMD prorofv_nr#I I lio,&** ii M kl'? I J

~ lbetter precision, the base spreading resistance Rbb`.additionnal integration of 100ns is used to determine, with aV — Y zssI,·-—TTy:[`—'iV , ,;et»¤·¤l * ” I

6>•t_. lo` Y I/I / mode. the total noise depends of the shaping time, Anl /lm e— eleE y‘V/ digitizing oscilloscope and a r.m.s. volmeter. In peaking

wwf e~+—ee; l I i.i. , .. I V; t . ,Another method to measure the r.m.s. noise voltage is to use a

figure 7

designer to predict the perfomiance ol tgircuit€,~——»»w_ __l ir 7 7t .ISEIN. ¥_ _»~~——ASIC development system. Its analysis capability allows the

‘‘“‘‘‘been done with Harris FAS'l“RA(`l<»ottw;ir·;. zi complete. . { Ft-; ` », .A;> CFD imirBu.—-acquisition 1V ?L]{ TZZLZ; `iiii 7 ` `F

reduces the radiation effect on devices) The simulation has ~—~»~` *’°tptautn Q

4GH2(pnp)i This dielectrically isolated ·, I()\/l ttcliiiiilogj.

ewv V l¢lASl-Vitrzmsition frequency (IT) viilut·i—. H(j}limipn> andSemiconductor UHF compiemeiitzuy bipolar process with

going to the integrator after suitable delay.specific integrated circuit is t:tri1ed out using Harris fraction diseiiminator to generate the gate signal, the other onenioumiiig devices) technology and then its implenientation in analog signal is splitted in two parts: one going to a constantFirsx this design has been evziluzued in SMD esurfaue gate. After front—end and post—amplifier (20db gain), the

noise charge by integrating the signal noise in a fixed timeiigurv method employed consists in the measurement of the r.m.s.

www ·-'EE

chain using gamma from a Cosource is used (figure 7). The57For noise measurements and calibration a classical analysis

$5*:* ga:NOISE PERFORMANCE

2%,.` ;Q') ij? 1,";n¤m

%' msu Y ` y ml figure 6

L M_ *i] vunrsv y »»L¢1?1.—r»L M:q;.. I »u4;c» V ` gx "’’

# M - ~’‘ 2::. m E@V(\0\N ?v¤·~4¢ balm] E EB`

tm

A-~ —?—— 4¤[;·mw>—# Yr~ . ;,»..2·s{:

§;w M »{’¤“r'+»-M+*· {wm ‘

v•c>vLC

Pulser equix alent noise charge = 2600e-ILMSphotodiode 1 lcmi, 50pF) and fora 100ns time gateobtained with the Harris chip coupled to PIN litunaniatsu

Figure 13 presents the results in gated integration mode. OCR Outputthan SMD prototype. Figure 10 shows the Co"' spectrum

with 100ns integration constant is used after posbampliiier.The Harris monolithic version is tested in the shine conditions

made with the same previous method. A fast shaping amplifier

Experimental noise measurements of the ASIC have beenHczrris ASI C pr0t0t)pe

figure l2BFRl82 trzmsistor.

E somv 25,0ns 0¤‘¤?‘46The value 0f Rbb’ obtained by these mcasurerrwnts is l2$2 for indi ls H C V C V éuitgioas

. .» .., Y \ addntonmal RC=1()Ons, (ENC)· = 1 1 1 3 Lu1;· + t196())W 2directot.1tput,(ENC)·* = (23.3 ( 1t11 ~ + 119-101~ at ei , I l O U `P` T l"`i`" C rrrr `L) jl“"£" Es i"— 1*

1 _ 1 J iHgun; 0

.,,,. .e.,, .,..m,4.t...,;,p4..,.~. 4-. 4

W.4. E troop? g ml W i 'mput cape" 1t\1z11» 111

0 20 40 60 so 100 M0 140 160

Mr " ‘‘»‘* r M TN M "1*"’“\ I I L J. ,, ,..,,.1, jiWW 0

M i·lh1» a assists;l%00 la -%

[BK Run 'IOOGS/5 Sample H————-·—+- —»-·»——-»-—4

2000with a total feedback capacitance CF = Cfi + Cfe = 0.67pF.ligure 12 (25ns/div) for three input capacitance, values and

5 ZSUO »•*/A Measured transient pulse responses on SOQ are shown in

E 3\’Ufigure ll

a i,1,.t..th,ishi.ahta_gmEE;iU} éFal} _ ll *1**

1~%—»l——l—%+—4Y {!p,1,,,43

· A r Hr7r—”

tg ’ aellrr wl ‘§tg};l(i5l 1 Lfi 1 , ,,, _ ,,,,_,;;_1000

`"`pf F ’ V ”""nmse n\&:as11rw`¤x—*¤· 1 +l`—»i1,_ :w2· .l11r

G 4.,,,: FE wif, ;__Y_ ;__ _,l nzciicr'»—•~ ,, t i j1 L 1 l ciéi ·a f1“`¥`“l"”i”] jyizxmplimudc zuamx

Thc ligurq “/ prcmnl the cxpuxi..;u\;¤ sumlh an peaking ee .,. 1—·—·—·-- ~+—r—·—, ` ——t~·· Asc 'l ` Y"/Vs? l 1 T ' T ll 1ye,1~1·,»·;~»%1—»~l;t—a

VI

Vex .tt. `,;.:.1;;‘g%:,t;;;:.?+r.$P~LT...ef—iigxmr

larger dynamic rangesiHPU[ (IPA {Hwf IQ}:limits of the processing time for detector signal, allows a

20 40 so ·»< iw Mu lmThis additionnal integration, which stays below the realistic¤’‘r ··" TM ‘ T M ‘· x‘*""·t·~·Tparallel to mtemal Cfi feedback capacitance (0.2pF) figure ll.1`= ;_k1Zz~ r .)5l*r'·>An external feedback capacitance (`fe (0.47pF) is added in

W ‘ gate : ’\*Ur`sji, 2000 ` -0 * Q, - figure lll` r/If ,0 ,s rr ” w I" ,_du» Inlinsflo //[Z- 25>0 ( -. 4 L 'k`,.h

4--A” - { »A" “ J5 3000 ee

, r,·/} $ }

112,06KcV3500,.1 *855

4000..,I/2

tax

t~ct>aa,·11 ettcrsasvtt eau ematiaous ccsv

20db step attenuation. figure 16 OCR Outputmodule for -4 charge injection values corresponding each to a (b)Figure 15 shows the output signals ot the Harris Dll.1-1

l(111ns/dtxtsio

80db. 1. 1,.11-1sigma equal to 5000e— and gain = 500. the dynamic range is20()ns integration time, the total charge is 25.10%-. With direcFor example, with a 2vo1ts maximum signal on 509 andsignal output to the smallest detectable signal. 1 ` rd, . .,.7.The dynamic range is the ratio ot the largest permissible

DYNAMIC RANGE mm 1 e—~ · 7 ~· - ~j ’1 i 1 111;:%..3Elt.é$,J _;__L(tE`t`*:i#§9•il*· T'? r ‘ 11i TT1-nt.;-in

keeping the total current constantlglperformances, several bipolar transistors can he paralleled, (alpnp UHFP3 transistor, we=50ttm . To achieve the best noise

1;·w nr l(1()ns/divistoriThe value of Rbb' obtained by these measurements is 90SZ for ... .-1.11 \‘RC : l()()nSZ (ENC); = (29.4 Ctm+118251z 2 FFT . E

RC = 20ns: (ENC)·(· = (36.9 Cim+ (14091z 2

figure 14 L 1 {Zta xw

0 20 40 60 >s~· 100 11*0 140 100 _ _/ v_ _ v_ Ftiurqatji. ` 2 } sun: | -- ;~,--» ~·»,» M TW ~--Y--1

72 hz as1000imag 45

-0 N.- eu .i00¤~V i3' `#°'

compared with a pulser response (figure 16a).-9* ·•<i ._’t1n> 2000 -——- 1 ;·—— r—r—·-¤~electrons. A long tail is observed for this crystal, figure 16b,avalanche photodiode C307l9E and excited by 4GeV

2 3000PbWO4 crystal of 23.52cm length coupled to EG&Gpresents the typical response registred with an hexagonal

E 4000.1- e—»»»e--»- » --~»-—»eV — /¤ Harris ASIC prototypes have been donellm. Figure 16(b)APD's. Hamamatsu and EG&G, associated to our SMD and

The measurements of the electronic noise due to the use of50001CERN BEAM TESTS

<»000 -.charge injection (Odb) and for 150ns base width pulse.

noise measurement (_peal<in;; (letertor) The output voltage limit, 2volts, is reached with a 40.10%For peaking detector mode: results are plotted in figure 14

figure 157 . 4 gate =150ns:(ENC1“ = (31.6 C1m— + (2.1(1812v

Rem 1 OD v 50 Ons 15:26:37gate = 250ns: (ENC); =(31.1(`in12 + ¢31(1(1»JMMCCWC M V `—M—u‘CQ¥A— 31 Aug 1995

figure U’+ ·—7é»11/

input c.ap.1mam» ap?) -j’ 3 i 1/ 1 1 Unstable `T I histogram2.10 Vorroe **-111/ 2 fe20 40 60 *0 11*** 1.71* 140 lol!

Refé Ampl.—~].----T..--¤-A,.‘—.._.I..*..]1 000 .” , 1 _...i— (- eerwe ‘ 0912. unstable histoqram

gy ·— gate: 25Um20DmVV‘"”“`1"`““"11\“7’T”53?;

Re1‘3 Ampl20dQ- 7 gate ](N|n:~ZODB -,Q histogram

er rr)L unstableR2 C—-‘— Refl Am 1 19.6mf/13 /¤ l -·-·-i»»·— ;;At&·;}5Un>

i@9.b@@histogram

'

E 3000 - —A·iP , ;¤¤YUnstable2.00mVF(‘1 i ur .. f 1i `i

Raft Ampl60dbA- r ,5 4000-.

Tek Rem 1 DOGS/s Average

4X ) ·- 1

5000-, supplies: +l()V and -8Vinjection at 0db = 40.100e

A - output signal on 50Qo0(1(1-_

—input capacitance, Cin : 12pFnoise measurexnemt r_;;.m~d ¤megr;m>r1

Test condition:

large dynamic range (2V output on 50SZtlow consumption == 15mW, (+1()\/) tor the tront-end.

peaking time =¤ 15ns,noise = 2500e- rms, gate=120ns. Harris ASIC prototypenoise ¤ 2100e- rms, gate=16()11s. SMD prototype.

For a 50pF input capacitance:

are measured.

The noise parameters of several transiinpedance prototypes

CONCLUSION

figure I>

0 20 40 he —0 100 120

25 0YA sl°* 50

I10] Y Benltammou et al., CMS TN/95-122 OCR OutputQ 75w ~ ‘>\1U proto Vol. NS—3(). N 1, February 1983, 319-323.

) ` é 100-J, e\A» x I9 H. Gatti, A. Hrisoho and P.F. Manfredi. IEEE Trans.Nucl. Science,0 ¤.¤iri~r~\$}t

cimento. Vol.9. N.l, 1986.$5 125.4 V #(-1,; detectors in e1ernentary—particle physics. Rivista del nuovo

QB} Ii. Gatti and P F. Manfredi, Processing the signals from solid—state150..* -·—1-·Nucl. Part. Sci. 1988. 38, 2l7·277.

III Veljko Radeka. Low-Noise Techniques In Detectors, Ann. Rev.175-{ ~·vr·*~experiments, Lisbon, September 1995.

200 16IW. Dabrowski et al., First workshop on electronics for LHCHamaiiitim. A"? I5] MA. Baturitsky et al . NIM A352 (1995) 604-609.

1992. 13()2—l306At gain 1()('I>. the noise is 25MeV for both prototypes Q4! I I Britton el til . 'I`rans.Nucl. Science. Vol. NS—39, N 5, OctoberAPD connected to SMD and Harris ASIC prototypes. 1989. 4074111.

l3iI\#I.MIV1i·r1i, Ii!`Ill1S.NLICi. Science. MI NS-36, N 1, FebruaryFigure 18 presents the noise metmurerneins tor Hzmizir1intsu—656for SMD.

Ill Afioltr. tl. Pessrnzl and P.G. Rancoita, NIM A292 (1990) 648At gain nertr 100, the noise is 25Me% mi i»\?4Et` iinti 155/1e\‘Il I P Iatron and M. Goyot, NIM. A2261 1984) 156-162.

REFERENCEfigure I T

Russia) for many profitable discussions and comments.l`” DU 4U ·w•‘~x·‘ (it thank B. llle (lPNLyon) and Y. Moussienko (I.N.R.,Moscow,

3. M .. .rr, W. NI04. support and integrated circuit layotrt . I would like also to

o · . - . Poneelet. SdM (Belgium), for prototype assistance, CAD

opportunity to be involved with RD32 and T. Melebeck, C.B` ` would like to thank J.C. Legrand of CERN for the

ACKNOWLEDGEMENTS=C § ioos} E .

match the ECAL dynamic range.

isn m integrate two channels (two gains) on single chip to$\¢fD—prt¤t··

down to values below 509.—r S \ i g *\ TZ y . .2 \ Q \reduce the input transistor base spreading resistance@’ ` 'iixrrh-ASIK200

(COB) technology to limit the connections length.use a smaller package (chip carrier) or chip on board

250The future improvments are :

EG&L§— APD and a typical Pbwk)4 crystal.

reached with APD’s photoreadout (EG&G and Hamamatsu)connected to SMD and Harris ASIC prototypesECAL electronic noise milestones requirements have beenFigure 17 shows the noise measurements tor EG&G—APDmonolithic preamplifier have been obtained. 1995 CMStype 2: Hamamatsu, S5345 (low C). 20mm¥. C`d=9()pFresults on the noise performance of the first run Harristype I; EG&G, C307 19E, 25mm·i- Cd=35pFelectronics in bipolar transistor technology. Encouragingof gzxin, respectively for two type oi APDS zu 27"(`These measurements show the feasability of front-endThe clccmmic noise in MeV has im·11 ¤11casu¤ui us za iu11u114m