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MATLAB/SIMULINK-Based High-Level Synthesis of Discrete-Time and Continuous-Time Sigma-Delta Modulators

Abstract

This paper describes a tool that combines an accurate SIMULINK-based time-domain behavioural simulator with a statistical optimizer for the automated high-level synthesis of ΣΔ Modulators (ΣΔMs). The combination of high accuracy, short CPU time and interoperability of different circuit models together with the efficiency of the optimization engine makes the proposed tool an advantageous alternative for ΣΔM synthesis. The implementation on the well-known MATLAB/SIMULINK platform brings numerous advantages in terms of data manipulation, flexibility and simulation with other electronic subsystems. Moreover, this is the first tool dealing with the synthesis of ΣΔMs using both Discrete-Time (DT) and Continuous-Time (CT) circuit techniques.

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MATLAB/SIMULINK-Based High-Level Synthesis of Discrete-Time and Continuous-Time Sigma-Delta Modulators

Author: Ruiz Amaya, Jesús; Rosa Utrera, José Manuel de la; Medeiro Hidalgo, Fernando; Fernández Fernández, Francisco Vidal; Río Fernández, Rocío del; Pérez Verdú, Belén; Rodríguez Vázquez, Ángel Benito
Publisher: Institute of Electrical and Electronics Engineers
Year: 2004
Source: https://idus.us.es/bitstreams/42e44fdc-10d6-4be1-9fc1-6572abf46407/download
(*)This wo k has been suppo ed by he EU ESPRIT IST P ojec
2001-34283/TAMES-2 and he Spanish CICYT P ojec TIC2001-0929/ADAVERE.
MATLAB/SIMULINK-Based High-Le el Syn hesis o Disc e e-Time and
Con inuous-Time 6' Modula o s
J. Ruiz-Amaya, J.M. de la Rosa, F. Medei o, F.V. Fe nández, R. del Río, B. Pé ez-Ve dú and A. Rod íguez-Vázquez
Ins i u o de Mic oelec ónica de Se illa  IMSE-CNM (CSIC)
Edi icio CICA-CNM, A da. Reina Me cedes s/n, 41012- Se illa, SPAIN
Phone: +34 95 5056666, Fax: +34 95 5056686, E-mail: [email p o ec ed]
Abs ac
This pape desc ibes a ool ha combines an accu a e
SIMULINK-based ime-domain beha iou al simula o wi h
a s a is ical op imize o he au oma ed high-le el syn he-
sis o
6'
Modula o s (
6'
Ms). The combina ion o high
accu acy, sho CPU ime and in e ope abili y o di e en
ci cui models oge he wi h he e iciency o he op imiza-
ion engine makes he p oposed ool an ad an ageous al e -
na i e o
6'
M syn hesis. The implemen a ion on he
well-known MATLAB/SIMULINK pla o m b ings nume -
ous ad an ages in e ms o da a manipula ion, lexibili y
and simula ion wi h o he elec onic subsys ems. Mo eo e ,
his is he i s ool dealing wi h he syn hesis o
6'
Ms using
bo h Disc e e-Time (DT) and Con inuous-Time (CT) ci cui
echniques(*).
1. In oduc ion
6' Analog o Digi al Con e e s (ADCs) ha e demon-
s a ed o be an a ac i e solu ion o he implemen a ion o
analog-digi al in e aces in sys ems-on-chip. Compa ed o
Nyquis - a e ADCs, 6' a chi ec u es p esen a be e pe -
o mance in e ms o esolu ion, speed and powe consump-
ion oge he wi h a high obus ness agains he una oidable
ci cui pa asi ics and ole ances [1][2][3]. Howe e , he
need o design high-pe o mance 6' ADCs in ad e se dig-
i al echnologies oge he wi h he e iginous a e imposed
by he echnology e olu ion has mo i a ed he in e es o
CAD ools which can op imize he design p ocedu e in
e ms o e iciency and sho ime- o-ma ke .
Fo his pu -
pose, se e al ools o o e sampling con e e syn hesis
ha e been epo ed in he las yea s [1][4][5][6][7]. These
ools use di e en syn hesis s a egies ha can be oughly
classi ied in o wo main ca ego ies [1][8]:
•Knowledge-based syn hesis- ools, which a e based on
cap u ing he knowledge o expe ienced designe s
[4][5]. Al hough he execu ion imes a e e y sho , he
esul s s ill mus be op imized because design p oce-
du es a e usually based on app oxima e equa ions and
e y simple models. Addi ionally, hey a e closed ools,
e.g., limi ed o a educed numbe o opologies and he
addi ion o new ones is a e y cos ly p ocess and usually
es ic ed o he ool de elope s.
•Op imiza ion-based syn hesis ools [1][6][7], which a e
based on an i e a i e op imiza ion p ocedu e wi h a pe -
o mance e alua o in he loop. Pe o mance e alua ion
can be done by means o equa ions o simula ions. In he
la e case, he cha ac e is ics o he simula o de e mine
he accu acy and openness o he ool.
Mos mode n app oaches [1][6][7] belong o he second
class o ools. Fig.1 shows he concep ual block diag am o
a con en ional op imiza ion-based syn hesis ool. The
design p ocess o a 6'0s a s om he high-le el modula-
o speci ica ions ( esolu ion, signal bandwid h, e c.). The
objec i e is o ge he building block speci ica ions (design
pa ame e s) ha op imize he pe o mance o he modula-
o ; ha is, hose speci ica ions which sa is y he modula o -
le el speci ica ions wi h he minimum powe consump ion
and silicon a ea. A each i e a ion o he op imiza ion p oce-
du e, ci cui pe o mances a e e alua ed a a gi en poin o
he design pa ame e space. Acco ding o such an e alua-
ion, a mo emen in he design pa ame e space is gene a ed
and he p ocess is epea ed again.
The i e a i e na u e o he op imiza ion p ocedu e
equi es a e y e icien mechanism o pe o mance e alu-
a ion. E en -d i en 6' beha io al simula ion is used in he
syn hesis app oaches in [1][6][7]. This echnique enables
e y e icien analysis while p o iding high accu acy le els.
In hese ools, bo h, simula ion engine and models, a e
implemen ed using a p og amming language like C. Modu-
la o lib a ies a e usually a ailable, con aining a limi ed
Fig. 1: Concep ual block diag am o an op imiza-
ion-based 6'M syn hesis ool.
New design
poin
Pe o mance
e alua ion
Specs
OK?
End No
Yes
Modula o
speci ica ions
Modula o
a chi ec u e
Ini ial design
poin
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numbe o a chi ec u es. Al hough a ex o g aphical in e -
ace is usually p o ided o c ea e new a chi ec u es, block
models canno be easily changed. On he o he hand, he
possible ci cui echniques used o implemen he modula-
o s a e cons ained by he capabili ies o he simula ion
engine and he a ailable block models. Fo his eason, he
syn hesis ools in [1][6][7] a e limi ed o disc e e- ime
Swi ched Capaci o (SC) 6'modula o s.
To o e come hese p oblems he p oposed
6'
syn hesis
Tool has been implemen ed using he MATLAB/SIMULINK
pla o m [9][10]. The embedded beha iou al simula o is
able o e icien ly e alua e he pe o mances o LowPass
(LP) o BandPass (BP)
6'
Ms implemen ed using ei he SC,
SwI ched Cu en (SI) o CT ci cui echniques. This enables
he syn hesis ool o deal wi h all hose ypes o
6'
Ms.
The implemen a ion on he MATLAB/SIMULINK pla -
o m p o ides a numbe o ad an ages: (a) i is a widely used
pla o m, amilia o a la ge numbe o enginee s, whe eas
special-pu pose ools [6][7] equi e o lea n a p op ie a y
ex -based o g aphical in e ace; (b) i has di ec access o
e y powe ul ools o signal p ocessing and da a manipu-
la ion; (c) i has comple e lexibili y o c ea e new
6'
M
a chi ec u es, and e en o include di e en blocks, ei he
con inuous- ime o disc e e- ime; and (d) i enables a high
lexibili y o he ex ension o he block lib a y whe eas add-
ing new blocks o models o exis ing lib a ies in p e ious
ools equi es he quali ied con ibu ion o a p og amme .
A comple e lis o non-ideali ies o he building blocks
o all ci cui echniques (SC, CT and SI) ha e been consid-
e ed [1][2][3]. The p ice o pay o he implemen a ion o
he beha io al models o he 6'M blocks (in eg a o s,
quan ize s, e c.) using elemen a y SIMULINK lib a y
blocks is a high compu a ional cos . To pallia e his p oblem
he beha io al models a e inco po a ed as SIMULINK
S- unc ions [11]. This app oach dec eases he compu a-
ional cos o accep able le els o syn hesis pu poses.
The op imiza ion ool a he co e o he syn hesis oolbox
con ains adap i e s a is ical op imiza ion echniques o
wide space explo a ion and de e minis ic echniques o
ine uning [1]. Besides, he addi ion o knowledge abou
speci ic a chi ec u es has been enabled. Such knowledge
can be coded using a s anda d p og amming language: C o
C++, is compiled a un- ime and inco po a ed in o he op i-
miza ion p ocess. This makes his syn hesis oolbox an op i-
miza ion-based syn hesis ool bu wi h he appealing
ea u es o knowledge-based sys ems.
This pape is o ganized as ollows. The cha ac e is ics o
he op imiza ion co e a e b ie ly desc ibed in Sec ion 2.
Sec ion 3 is de o ed o he pe o mance e alua o : he
beha iou al simula o SIMSIDES. Finally, Sec ion 4 gi es
se e al simula ion and syn hesis examples o he p oposed
oolbox.
2. Op imiza ion co e
The p esen ed syn hesis ool uses an op imiza ion co e
o design pa ame e selec ion as desc ibed abo e. De e -
minis ic op imiza ion me hods, like hose a ailable in he
MATLAB s anda d dis ibu ion [9], a e no sui able because
ini ially we may ha e li le o no idea o an app op ia e
design poin . The e o e, he op imiza ion p ocedu e is
quickly apped in a local minimum.
Fo his eason, we de eloped an op imize which com-
bines an adap i e s a is ical op imiza ion algo i hm inspi ed
in simula ed annealing (local minima o he cos unc ion
can hen be a oided) wi h a design-o ien ed o mula ion o
he cos unc ion (which accoun s o he modula o pe o -
mances).
Fig.2 shows he low diag am o he op imize whe e
s a ing om a modula o opology, e.g., a modula o whose
design pa ame e s (building block speci ica ions) a e no
known and a bi a y ini ial condi ions, a se o design
pa ame e pe u ba ions is gene a ed. Wi h he new design
pa ame e s, a se o simula ions a e pe o med o e alua e
he modula o pe o mance. F om he simula ion esul s, i
au oma ically builds a cos unc ion ( ha has o be mini-
mized). The ype and alue o he pe u ba ions as well as
he i e a ion accep ance o ejec ion c i e ia depend on he
selec ed op imiza ion me hod. The op imiza ion p ocess is
di ided in o wo s eps:
• The i s s ep explo es he design space by di iding i
in o a mul i-dimensional coa se g id, esul ing in a mesh
o hype cubes (main op imiza ion). A s a is ical me hod
is usually applied in his s ep.
• Once he op imum hype cube has been ob ained, a inal
op imiza ion is pe o med inside his hype cube (local
op imiza ion). A de e minis ic me hod is usually used in
his s ep.
DESIGN SPACE
DISCRETIZATION
MAIN
OPTIMIZATION
COST FUNCTION
EVALUATION
END?
UPDATE DESIGN
PARAMETERS
LOCAL
OPTIMIZATION
No
Yes
MODULATOR
TOPOLOGY
Fig. 2: Ope a ion low o he op imiza ion co e.
END?
UPDATE DESIGN
PARAMETERS
No
PERFOMANCE
EVALUATOR
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In addi ion, he op imiza ion co e is e y lexible, in so
a as he cos unc ion o mula ion is e y e sa ile: mul i-
ple a ge s wi h se e al weigh s, cons ain s, dependen
a iables, and loga i hmic g ids a e pe mi ed. This op imi-
za ion p ocedu e has been ex ensi ely es ed wi h design
p oblems in ol ing beha iou al simula o s as well as elec-
ical simula o s [1][7].
This op imize has been in eg a ed in he MATLAB/SIM-
ULINK pla o m by using he MATLAB engine lib a y [9],
so ha he op imiza ion co e uns in backg ound while
MATLAB ac s as a compu a ion engine.
3. Beha iou al simula o : SIMSIDES
As desc ibed in Sec ion 1, he p oposed syn hesis ool
uses a simula o as a pe o mance e alua o . 6'Ms a e
s ongly non-linea ci cui s and, he e o e, e alua ion o
hei main pe o mance speci ica ions has o be ca ied ou
in he ime-domain. Due o he o e sampling na u e o
6'Ms, his means ha long ansien simula ions (se e al
housands o clock cycles) a e necessa y o e alua e hei
main igu es o me i .
T ansis o -le el simula ions using SPICE-like simula o s
lead o excessi e CPU imes ( ypically om days o weeks
[12]), because hey base i s analysis in nume ical in eg a-
ion, wi h small in eg a ion s eps and complex de ice mod-
els. To o e come his p oblem, di e en al e na i es ha e
been de eloped, which a he p ice o losing some accu acy
in hei esul s, educe he simula ion ime [1]. One o he
bes accu acy-speed ade-o s is achie ed by using he
so-called
beha iou al simula ion
echnique using unc ional
models [6][7][13][14]. This app oach equi es ha he ci -
cui can be pa i ioned in o basic blocks wi h independen
unc ionali y. This implies ha an ins an aneous block ou -
pu canno be ela ed o i sel , ha is, ei he he e is no global
eedback loop, o , in case such a loop exis s, he e is a delay
ha a oids he ins an aneous dependence. These blocks a e
desc ibed by equa ions ha ela e he ou pu s in e ms o he
inpu s and he in e nal s a e a iables. Thus, he accu acy o
he simula ion depends on how p ecisely hose equa ions
desc ibe he eal beha iou o each block.
This has been he echnique used in ou simula o , called
SIMSIDES (SIMulink-based SIgma-DEl a Simula o ). This
simula o has been implemen ed as a oolbox in he MAT-
LAB/SIMULINK pla o m. Modelling and simula ion o
6'
Ms in his pla o m was i s epo ed in [15][16], al hough
limi ed o SC a chi ec u es. Al hough e y in ui i e, he
implemen a ion o he beha io al models o each basic build-
ing block equi es se e al se s o elemen a y SIMULINK
blocks. This means a penal y in compu a ion ime which may
become c i ical in an op imiza ion-based syn hesis p ocess in
which hund eds o housands o simula ions mus be exe-
cu ed. To o e come his p oblem, beha iou al models in
SIMSIDES ha e been inco po a ed in SIMULINK by using
S- unc ions [11]. As a consequence, he CPU ime o he
ime-domain simula ion o a DT/CT
6'
M in ol ing 65536
samples is ypically a ew seconds
†
. Besides, SIMSIDES is
able o deal wi h any ci cui echnique: SC, SI o CT.
SIMSIDES con ains a se o 6'M block lib a ies which
a e classi ied acco ding o he modula o hie a chy le el
and he ci cui echnique. The basic building blocks mod-
elled in SIMSIDES, as well as i s non-ideali ies a e summa-
ized in Table 1. A de ailed desc ip ion o hese
non-ideali ies and hei beha iou al models can be ound in
[1], [2] and [3] o SC, CT and SI ci cui s, espec i ely.
Fig.3 shows he gene al s uc u e o SIMSIDES. Fi s ,
he modula o a chi ec u e is de ined by connec ing he
building blocks o he SIMSIDES lib a ies. A e he ci cui
diag am is c ea ed, he use se s some pa ame e s and
op ions which a e aken in o accoun by he ool o pe o m
he ime-domain simula ion. Mon e-Ca lo simula ion as
well as pa ame ic analysis a e also possible. Ou pu da a
gene a ed by simula ion consis s o ime-domain se ies
which can be p ocessed o ge di e en igu es o me i .
Thus, his og ams and ou pu spec a a e compu ed using he
ou ines p o ided by he signal p ocessing oolbox o MAT-
LAB. O he analyses such as Signal- o-Noise Ra io (SNR),
ha monic o in e modula ion dis o ion, a e done using a
collec ion o unc ions speci ically de eloped o SIM-
SIDES.
The quali y o he syn hesis app oach is no only gi en by
i s e iciency in e ms o CPU ime. I also c i ically depends
on he accu acy o he pe o mance e alua o . To illus a e
†. All simula ions shown in his pape we e done using a PC wi h an AMD
XP2400 CPU@2GHz @512MB-RAM.
TABLE 1: Basic building blocks and non-ideali ies
modelled in SIMSIDES.
Ci cui
echnique
Block Non-ideali ies
SC
In eg a o s
Opamps
Fini e and non-linea gain, dynamic limi a ions
(incomple e se ling e o , ha monic dis o ion), ou pu
ange, he mal noise.
Swi ches The mal noise, ini e and non-linea esis ance.
Capaci o s Non-linea i y, misma ching.
Resona o s Non-ideali ies associa ed o he in eg a o s.
SI
In eg a o s
Fini e and non-linea gain, ini e ou pu and inpu con-
duc ance, dynamic limi a ions (incomple e se ling,
ha monic dis o ion, cha ge injec ion), he mal noise.
Resona o s Feedback gain e o , non-ideali ies associa ed o he
in eg a o s.
CT In eg a o s
Fini e and non-linea gain, dynamic limi a ions (pa a-
si ic capaci o s, high and low equency poles), he -
mal noise, ou pu ange and lineal inpu ange, o se .
Resona o s Non-ideali ies associa ed o he in eg a o s.
ALL
Clock Ji e .
Compa a o s O se , hys e esis.
Quan ize s
/DACs
In eg al non-linea i y, gain e o , o se , ji e noise,
delay ime.
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he accu acy achie ed by he beha iou al models in SIM-
SIDES, Fig.4 shows he ou pu spec um o a SC cascade
2-1-1 modula o in ended o ADSL applica ion [17]. The
h ee plo s co espond o a beha iou al simula ion using
SIMSIDES, an elec ical simula ion using HSPICE (5 days
o CPU ime o 8192 samples) and eal measu emen s
aken om a chip p o o ype. A di e en signal equency
has been chosen o HSPICE o be e compa ison.
4. The 6' Syn hesis oolbox in ope a ion
The p oposed ool has been concei ed as a MATLAB ool-
box o he simula ion and syn hesis o
6'
Ms. The G aphical
Use In e ace (GUI) included in he oolbox allows o na i-
ga e easily h ough all s eps o he simula ion, syn hesis and
pos -p ocessing o esul s.
Fo illus a ion pu poses, Fig.5
shows pa o he oolbox GUI o a chi ec u e desc ip ion.
By using his GUI, he use can ei he open an exis ing
6'M a chi ec u e o c ea e a new one in he SIMULINK
pla o m. When a simula ion is inished, di e en pe o -
mance igu es such as ou pu spec um, in-band noise
powe , ha monic dis o ion, e c. can be compu ed om he
ou pu da a h ough he analysis/da a p ocessing menu. In
addi ion, pa ame ic analysis and Mon eCa lo simula ions
can be pe o med.
High-le el syn hesis is s a ed om he syn hesis menu,
whe e cons ain s, pe o mance speci ica ions, design
pa ame e s, op imiza ion algo i hms, e c., can be speci ied.
Then, he op imiza ion co e s a s he explo a ion o he
design space o ind ou he op imum solu ion by using
SIMSIDES esul s o pe o mance e alua ion.
To illus a e he simula ion and syn hesis capabili ies o
his oolbox wo 6'M a chi ec u es ha e been selec ed:
•
An SC 2-1 cascade single bi
6'
M (SC 2-1 sb) (Fig.6(a))
.
• A CT 5 h-o de LP 6'M (CT 5 h-o de LP) (Fig.6(b)).
One o he mos impo an deg ading ac o s in SC cas-
cades 6'Ms is he misma ch e o . This is illus a ed in he
Mon eCa lo simula ion o Fig.7(a), whe e a andom Gauss-
ian misma ch e o wi h ze o mean and 0.5% s anda d de i-
a ion has been assumed. Each plo co esponds o a
pa ame ic analysis o he SNR e sus he inpu ampli ude.
Abou 450 simula ions wi h 32768 samples we e done o
ob ain his igu e and i only ook 541s CPU ime. Apa
om mis ma ch e o , he mal noise can deg ade conside -
ably he esolu ion. Fig.7(b) illus a es he pe o mance
deg ada ion o he 2-1 sb modula o caused by all he mal
noise sou ces.
On he o he hand, one o he majo ad an ages o CT
6'
Ms lies in ha hey can achie e highe sampling equen-
cies. Howe e , CT
6'
Ms deg ade d as ically hei pe o m-
ance as a esul o wo impo an e o s: clock ji e noise and
delay ime be ween he quan ize clock edge and DAC
esponse. Fig.8(a) shows he impac o he delay on he ou pu
spec um o he modula o o Fig.6(b). Two di e en cases
Fig. 3: S uc u e o SIMSIDES.
SIMSIDES -TBOX
SIMSIDES CIRCUIT
DESCRIPTION
MONTECARLO
SNR
SIMSIDES -TBOX
SIGNAL
TIME DOMAIN
PSD
TOPOLOGIC
THD HISTOGRAM
SIGNAL
LIBRARIES DESCRIPTION
SIMULATION
PROCESSING
PROCESSING
TOOLBOX
ANALYSIS
PARAMETRIC
ANALYSIS
MATLAB/SIMULINK En i onmen
/ MATLAB
Fig. 4: Simula ion o a SC cascade 2-1-1.
104105106107
-200
-150
-100
-50
F equency (Hz)
PSD (dB/Hz)
Measu ed
HSPICE
SIMSIDES
Fig. 5: Illus a ing he GUI o edi ing modula o opolo-
gies o he 6' Syn hesis Toolbox.
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ha e been conside ed: a ixed delay, which is independen on
quan ize inpu ol age magni ude; and a signal-dependen
delay, which is p ac ically cons an o la ge quan ize inpu
ol ages, bu ises o dec easing inpu s [2]. Fig.8(b) illus-
a es he pe o mance deg ada ion caused by ji e noise
whe e a andom Gaussian ji e noise wi h ze o mean and
s anda d de ia ion has been assumed.
To show he capabili ies o he Syn hesis Toolbox, he
high-le el sizing o he modula o s in Fig.6 is pe o med.
The modula o speci ica ions a e: 15bi s@20kHz o he SC
2-1 sb 6'M and [email p o ec ed] o he CT 5 h-o de LP
6'M. The objec i e is o mee hose speci ica ions wi h he
minimum powe consump ion and silicon a ea.Once design
pa ame e s, design speci ica ions, and cons ain s ha e been
speci ied h ough he oolbox GUI, a wide explo a ion o
he design space is pe o med by he op imize . A each
poin o he design space a SIMSIDES simula ion is done o
e alua e he modula o pe o mances.
Table 2 and Table 3 show he esul s o he high-le el syn hesis
o bo h modula o s.
The op imiza ion p ocedu es equi ed
817 i e a ions o he SC 2-1 sb modula o and 674 i e a-
ions o he CT 5 h-LP6' aking 16.4 minu es and 52.1
minu es o CPU ime, espec i ely. Finally, Fig.9 illus a es
bo h ou pu spec a and Signal- o-Noise plus Dis o ion
Ra io (SNDR) co esponding o he high-le el sizing p o-
ided by he syn hesis oolbox.
Conclusions
A ool o he syn hesis o CT and DT
6'
Ms in he MAT-
LAB/SIMULINK en i onmen has been desc ibed. Based
y
Thi d In eg a o
Second In eg a o
Fi s In eg a o
Cancela ion
Logic
Cancella ion
Logic
gmC-in eg a o 5gmC-in eg a o 4gmC-in eg a o 3gmC-in eg a o 2gmC-in eg a o
T ansconduc o 6
T ansconduc o 5
T ansconduc o 4
T ansconduc o 3
T ansconduc o 2
T ansconduc o 1
T ansconduc o
y
To Wo k s p
a
Sine Wa e
Real_DAC_Mul ibi _delay_ji e
Ideal_Compa a o
G ound1G ound
(a)
(b)
Fig. 6: Block diag ams o he (a) SC 2-1 sb
6'
M and
(b)
CT 5 h-o de LP
6'
M
.
104106
-120
-100
-80
-60
-40
-20
0
F
eque
n
cy (
Hz
)
Rela i e Magni ude (dB)
Ideal
The mal noise
Fig. 7: E ec o (a) misma ch e o and (b) he mal noise
on SC 2-1 sb
6'
M
.
(a)
(b)
-60 -50 -40 -30 -20 -10 0
40
50
60
70
80
90
100
SNR
R
e
l
a
i
e
In
pu
Am
p
li
ude (d
B
)
(dB)
10-6 10-5 10-4 10-3
70
75
80
85
90
95
U
SNR (dB)
104106108
-160
-140
-120
-100
-80
-60
-40
-20
F e
q
uenc
y(
Hz
)
Rela i e Magni ude (dB)
Ideal
ixed delay
signal-dependen delay
(a)
(b)
Fig. 8: E ec o (a) loop delay ime and (b) clock ji e
noise on CT 5 h-LP
6'
M
.
Vji UTs
=
P oceedings o he Design, Au oma ion and Tes in Eu ope Con e ence and Exhibi ion Designe s’ Fo um (DATE’04)
1530-1591/04 $20.00 © 2004 IEEE

on he combina ion o an accu a e and e icien SIM-
ULINK-based ime-domain beha iou al simula o and an
ad anced s a is ical op imize , he p oposed ool allows o
e icien ly map he modula o speci ica ions in o build-
ing-block speci ica ions in easonable compu a ion imes.
To he bes o ou knowledge, his is he i s ool ha is able
o syn hesize an a bi a y
6'
M a chi ec u e using any ci cui
echnique (SC, SI o CT). The implemen a ion in he MAT-
LAB/SIMULINK pla o m b ings also nume ous ad an-
ages wi h a ela i ely low penal y in compu a ion ime.
Re e ences
[1] F. Medei o, B. Pé ez-Ve dú, and A. Rod íguez-Vázquez: Top-Down
Design o High-Pe o mance Modula o s, Kluwe , 1999.
[2] J. A. Che y and W. M. Snelg o e: Con inuous-Time Del a-Sigma
Modula o s o High-Speed A/D Con e sion: Theo y, P ac ice and
Fundamen al Pe o mance Limi s,
Kluwe , 2000.
[3] J. M. de la Rosa, B. Pé ez-Ve dú and A. Rod íguez-Vázquez: Sys em-
a ic Design o CMOS Swi ched-Cu en Bandpass Sigma-Del a Mod-
ula o s o Digi al Communica ions Chips, Kluwe , 2002.
[4] G. F.M. Beenke , J.D. Conway, G. G. Sch oo en and A. G.J. Slen e :
“Analog CAD o Consume ICs”, in P oc. Wo kshop on Ad ances in
Analog Ci cui Design, pp. 343-355, 1992.
[5] M.F. Ma and R.W. B ode sen: “A Design Sys em o On-Chip O e -
sampling A/D In e aces”, IEEE T ansac ions on VLSI Sys ems, Vo l .
3, pp. 345-354, Sep embe 1995.
[6] K. F ancken, P. Vanco enland and G. Gielen: “DAISY: A Simula-
ion-Based High-Le el Syn hesis Tool o '6 Modula o s”, P oc.
IEEE In . Con . Compu e -Aided Design, pp. 188-192, 2000.
[7] F. Medei o, B. Pé ez-Ve dú, A. Rod íguez-Vázquez and J.L. Hue as:
“A e ically In eg a ed ool o Au oma ed Design o Modula-
o s”, IEEE Jou nal o Solid-S a e Ci cui s, Vol. 30, No. 7, July 1995.
[8] G.G. E. Gielen and R.A. Ru enba : “Compu e -Aided Design o Ana-
log and Mixed-Signal In eg a ed Ci cui s”, P oceedings o he IEEE,
Vol. 88, pp. 1825-1852, Decembe 2000.
[9] The Ma hWo ks Inc.:Using MATLAB Ve sion 6”, July 2002.
[10] The Ma hWo ks Inc.: “Using Simulink Ve sion 5”, July 2002.
[11] The Ma hWo ks Inc.: “W i ing S-Func ions Ve sion 5”, July 2002.
[12] V. F. Dias, V. Libe ali and F. Malobe i: “Design Tools o O e sam-
pling Da a Con e e s: Needs and Solu ions”, Mic oelec onics Jou -
nal, Vol. 23, pp. 641-650, 1992.
[13] C. H. Wol and L. Ca ley: “Simula ion o '6 Modula o s Using
Beha io al Models”, P oc. IEEE In . Symp. Ci cui s and Sys ems, pp.
376-379, 1990.
[14] V. Libe ali, V.F. Dias, M. Ciapponi and F. Malobe i, “TOSCA: a Sim-
ula o o Swi ched-Capaci o Noise-Shaping A/D Con e e s,” IEEE
T ans. Compu e -Aided Design, Vol. 12, pp. 1376-1386, Sep . 1993.
[15] S. B iga i, F. F ancesconi, P. Malco a i, D. Tonie o, A. Baschi o o
and F. Malobe i: "Modeling Sigma-Del a Modula o Non-ideali ies in
SIMULINK", P oc. IEEE In . Symp. Ci cui s and Sys ems, pp.
II.384-387, 1999.
[16] P. Malco a i, S. B iga i, F. F ancesconi, F. Malobe i, P. Cusi ano and
A. Baschi o o: “Beha iou al Modeling o Swi ched-Capaci o
Sigma-Del a Modula o s”, IEEE T ans. on Ci cui s and Sys ems-I, pp.
352-364, Ma ch 2003.
[17] F. Medei o e al.: “Design o a B oadband 6' Modula o in 2.5V
CMOS”, P oc. Design, Au oma ion and Tes in Eu ope: Designe s’
Fo um, pp. 219-223, 2002.
TABLE 2:
High-le el syn hesis esul s o SC 2-1 sb
6'M
.
OPTIMIZED SPECS FOR: 15bi s@20kHz
In eg. I In eg. II-III
Modula o Sampling equency (MHz) 5.12
O e sampling a io 128
In eg a o s
Sampling capaci o 61.5
Feed-back capaci o 24 3
MOS swi ch-ON esis ance ( )
Opamps
DC-gain (dB)
DC-gain non-linea i y
Ou pu swing (V) 2.7
Inpu noise PSD
Ou pu cu en (mA)
Inpu ansconduc ance (mA/V)
Compa a o s Hys e esis (V)
Technology Cap. non-linea i y (ppm/ )
TABLE 3:
Syn hesis esul s o CT 5 h-o de LP
6'M.
OPTIMIZED SPECS FOR: [email p o ec ed]
In eg. I
O he In eg.
Modula o Sampling equency (MHz) 300
O e sampling a io 40
T ansconduc o s
T ansconduc ance (mA/V) 0.6 0.15
DC-gain (dB)
Pa asi ic ou pu capaci o (pF)
Inpu linea swing (V)
HD3 (dB)
DAC Clock ji e (ps)
Excess loop delay ime (ns)
CipF
CopF
k:0.84d1.7d
58.5 56
V2–
 22%d22%d
nV sq Hze8.1d278d
0.5 0.23
0.5 0.14
0.2d
V289d
34 42
0.66d0.04d
0.5 0.32
50–d30–d
0.5d
0.77d
104105106
-150
-100
-50
0
Rela i e Magni ude (dB)
F e
q
uenc
y(
Hz
)
SNDR=77.40dB
103104105
-150
-100
-50
0
Rela i e Magni ude (dB)
F e
q
uenc
y(
Hz
)
SNDR=91.78dB
(b)
(a)
Fig. 9: Ou pu spec a and SNDR o he syn hesized
(a) SC 2-1 sb and (b) CT 5 h-o de LP
6'
M
s.
6'
P oceedings o he Design, Au oma ion and Tes in Eu ope Con e ence and Exhibi ion Designe s’ Fo um (DATE’04)
1530-1591/04 $20.00 © 2004 IEEE