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Summary
Complex ΔΣ DA modulator
Study of Complex Multi-Bandpass#DWA algorithm for I-Q Signal Generation
P75
M. Murakami, S. Mohyar, H. Kobayashi, T. Matsuura, O. Kobayashi†, M. Tsuji†, S. Umeda†,R. Shiota†, N. Dobashi†, M. Watanabe†, I. Shimizu, K. Niitsu‡, N. Takai, T. J. Yamaguchi"
Dept. of Electrical Engineering, Graduate School of Engineering, Gunma University†STARC, ‡Nagoya University
Complex multi-bandpass DWA
DWA algorithm
*Data Weighted Averaging|Select the element with DSP algorithm
Introduction
‣ Multi-bit DAC
◎ Relaxes the analog filter requirements
× Degrades system linearity
◎ DWA algorithm
Low cost, high quality I,Q signal generation.
‣ Complex multi-BP ΔΣ DAC
‣ I,Q signal generation with digital centric for testing communication IC.
!"#$%&%'()'(
!"#$%&'*#"+)#,,-./$(01
2/&/(#$ !"#$%&
2!3
2!3
2/&/(#$/")'(
!!!"#"#
!!!#"#"
!"#$%&'(*#"+)#,,-4%+'$#(%1 DWA
δI
δQ
Simulation result ~Actual Non-Linear DAC + DWA~
-140
-120
-100
-80
-60
-40
-20
0
-0. 5 -0. 4 -0. 3 -0. 2 -0. 1 0 0. 1 0. 2 0. 3 0. 4 0. 5
Po
we
r [d
B]
in / s
w/o DWA
-140
-120
-100
-80
-60
-40
-20
0
-0. 5 -0. 4 -0. 3 -0. 2 -0. 1 0 0. 1 0. 2 0. 3 0. 4 0. 5
Po
we
r [d
B]
in / s
w/ Complex DWA
DWA
Steep NotchesNotches filled with noise
DWA
0
10
20
30
40
50
60
1 2 3 4 5 6
SN
DR
[d
B]
OSR (2n)
w/o Complex DWA
Complex DWA
w/
Complex Multi-Bandpass DWA algorithm
DAC2(HP operation)DAC1(LP operation)
DAC
Inpu
tD
AC
Inp
ut
TIME
Iin
4
3
2
2
6
1
7
5
Qin I0 I1 I2 I3 I4 I5 I6 I7
2
2
6
1
7
5
4
3
Iin
4
3
2
2
6
1
7
5
Qin I0 I1 I2 I3 I4 I5 I6 I7
2
2
6
1
7
5
4
3
N = 4(four zero points)
DWA = ΔΣNon-Linearity
z -1DAC Output
z -1Input
δ
Can’t be realized directly
Integration Differentiation
δ affected by only Differentiation
DACPointer
InputOutput
Equivalent circuit for implementationMemorize!next cell selection start point
δ
!"#$%&'()
*%+,
#-..$$/(01-2%3 %4 %5 %6 %7 %8 %9 %:
7
6
5
9
8
4
:
!"#$%&'()*
Memorize!next cell selection start point
S1
S2
S3S4
S5
S6
S7S0
VDD
VDD
VDD
VDD
VDD VDD
VDDVDD
I + e0
I + e1
I + e2
I + e3I + e4
I + e5
I + e6
I + e7
Vout
R
DWA DAC
Multi-bit DAC + DWA*
S1 S2 S7S0
I + e0 I + e1 I + e2 I + e7
R
VDD
Vout
Multi-bit DAC
!"#$%&'()
*%+,
#-..$$/(01-2%3 %4 %5 %6 %7 %8 %9 %:
7
6
5
9
8
4
:
Accumulate mismatch of particular cell
Normal unary DAC!"#
ei : current source mismatch
Multi-bit DA modulator
Multi-bit DA modulator(2~3bit)
Quantization noise reduction Linearity degradation
Relax
Down
1bit
Multi-bit
Error
Digital
Analog
2nd-order complex multi-BP ΔΣ DAC
EI
EQ
a b
d
d c
c
b
Iin
Qin
Iout
Qout
H(z)
a
DACI
DACQ
H(z)
Out
put
sp
ectr
um
N = 1 N = 4
Single-band Multi-band
EI
EQ
a b
d
d c
c
b
Iin
Qin
Iout
Qout
H(z)
a
DACI
DACQ
H(z)
EI
EQ
a b
d
d c
c
b
Iin
Qin
Iout
Qout
H(z)
a
DACI
DACQ
H(z)
DAC
DAC
-140
-120
-100
-80
-60
-40
-20
0
-0. 5 -0. 4 -0. 3 -0. 2 -0. 1 0 0. 1 0. 2 0. 3 0. 4 0. 5
Po
we
r [d
B]
in / s
-140
-120
-100
-80
-60
-40
-20
0
-0. 5 -0. 4 -0. 3 -0. 2 -0. 1 0 0. 1 0. 2 0. 3 0. 4 0. 5
Po
we
r [d
B]
in / s
Principle of complex BP noise shape
QoutQin
IoutIinEI
EQ
H(z)
DAC
DAC
Complexresonator
+1
1 + H(z)(EI + jEQ)
Iout + jQout =H(z)
1 + H(z)(Iin + jQin)
Power
ω
H(z)Quantization noises
Signal Transfer Function = 1
Noise Transfer Function = 0
Research Objective
Multi-bit DA modulator(2~3bit)
Linearity degradation
Low quality signal
DWA algorithm
High quality signal
Research Objective
Low cost, high quality signal
High quality testing
ΔΣ Complex
+Bandpass
Filter
Analogoutput
Digitalinput
...0101DACDSP
testingsignal
Research Background
Co
st
(C
en
ts /
Tra
nsis
tor)
テストコストの傾向(ITRS 2001)
コスト
(Cents / Transistor)
年
Silicon
Testing
1
10-3
10-6
1990 1995 2000 2005 2010 2015
Year
Demand for communication IC testing
Silicon cost
Testing cost
Lower
Higher
::