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Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
100-1000 GHz Bipolar ICs:
Device and Circuit Design Principles
Mark Rodwell, UCSB Munkyo Seo, Teledyne Scientific
Short Course, IEEE Bipolar / BiCMOS Circuits and Technology Meeting, 9 October 2011, Atlanta, Georgia
[email protected] , [email protected]
Collaborators:
UCSB HBT Team: V. Jain, E. Lobisser, A. Baraskar, J. Rode, H.W. Chiang, A. C. Gossard , B. J. Thibeault, W. Mitchell
Teledyne HBT Team: M. Urteaga, R. Pierson, P. Rowell, B. Brar, Teledyne Scientific Company
Teledyne IC Design Team: J. Hacker, Z. Griffith, A. Young, M. J. Choe, Teledyne Scientific Company
UCSB IC Design Team: S. Danesgar, T. Reed, Eli Bloch, H-C Park, J-H Kim
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Motivation /
Overview
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
DC to Daylight. Far-Infrared Electronics
0.3- 3 THz imaging systems
109
1010
1011
1012
1013
1014
1015
Frequency (Hz)
microwave
3-30 GHz
mm-wave
30-300 GHz
far-IR
(sub-mm)
0.3-3THz
mid-IR
3-30 THz
near-IR
30-450 THz
op
tica
l
45
0-9
00
TH
zHow high in frequency can we push electronics ?
...and what would be do with it ?
0.3-3 THz radio: vast capacity bandwidth, # channels
0.1-1 Tb/s optical fiber links
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
THz Transistors: Not Only For THz Circuits
THz amplifiers→ THz radios → imaging, sensing, communications
precision analog design at microwave frequencies → high-performance receivers
500 GHz digital logic → fiber optics
Higher-Resolution Microwave ADCs, DACs, DDSs
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
ICs to 600 GHz : Teledyne and UCSB
570 GHz fundamental VCO
340 GHz dynamic frequency divider
Vout
VEE VBB
Vtune
Vout
VEE VBB
Vtune
430 GHz low-noise amplifier M. Seo, TSC other ICs by J. Hacker
M. Seo, TSC CSIC 2010
M. Seo, TSC IEEE MWCL 2010
204 GHz static frequency divider (ECL master-slave latch)
Z. Griffith, TSC CSIC 2010
300 GHz fundamental PLL M. Seo, TSC IMS 2011
40 GHz op-amp with 54 dBm IP3 at 2 GHz
Z. Griffith, TSC IMS 2011
220 GHz 48 mW power amplifier
T. Reed, UCSB CSIC 2011
Other ICs in design: 30-40 GS/s track/hold optical PLLs coherent optical receivers 340 GHz arrays
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
At High Frequencies The Atmosphere Is Opaque Mark Rosker
IEEE IMS 2007
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
THz Bipolar Transistors: Where Next ?
array transmitters: critical for sub-mm-wave radio / radar
32 x 32 array → 60-90 dB increased SNR →vastly increased range
Rtransmitreceive
transmit
received eR
NN
P
P 2
2
16
0
20
40
60
80
100
106
107
108
109
1010
1011
1012
Sta
ge
Volta
ge
Gain
, d
B
Frequency, Hz
gain @ 100 MHzdesign frequency
)||||(
decreasing
outloadin, RRRg xm
0
20
40
60
80
100
106
107
108
109
1010
1011
1012
Sta
ge
Volta
ge
Gain
, d
B
Frequency, Hz
)/( ,,
increasing
max loadbias CIff
HBT / HEMT integration for mixed-signal III-V NFET vs. Si PFET active loads: much lower Cload/Ibias
LSI @ 128 nm node: scaled interconnects high packing density → speed, power
32 nm / 3 THz node, beyond Transition to production
340 GHz 670 GHz 1080 GHz
R&D→ pilot → foundry design tools, reliability, scaled interconnects CMOS control integration: 3-D, flip chip
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Bipolar Transistors:
Models,
Scaling Laws,
State of Art,
Roadmaps
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Bipolar Transistor: Structure & Models
nkTqIg Em /
)( cbmjebe gCC
mbe gR /
""
2
2/
/2/
satcc
thermalbnbb
vT
vTDT
collex
E
bc
E
jecollectorbase RRqI
nkTC
qI
nkTC
f
2
1
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Base-Collector Distributed RC Parasitics
emitteremittercontactex AR /,
Eesspread LWR 12/ ELlength emitter
Egapsgap LWR 4/
Ebcscontactspread LWR 6/,
contactsbasebasecontactcontact AR _, /
cemitterecb TAC /,
cgapgapcb TAC /,
ccontactsbasecontactcb TAC /_,
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
RbbCcb Time Constant, Fmax , Simple Hybrid- model
where8max cbibbCRff
)(
)2/(
,,
,,
,
spreadgapcontactspreadcontactecb
gapcontactspreadcontactgapcb
contactcontactcbcbibbcb
RRRRC
RRRC
RCCR
above from fit set to ratio :
total true
resistance base totaltrue
maxfCC
CCC
R
cbxcbi
cbcbxcbi
bb
Vaidyanathan & Pulfrey IEEE Trans. Elect. Dev. Feb. 1999
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Key 2nd-Order Effects in III-V HBTs: Omitted for Brevity
Betser and Ritter , IEEE Trans. Elect. Dev., April 1999 Urteaga & Rodwell, IEEE Trans. Elect. Dev., July 2003
c decreases :overshoot velocity induced-Current
.modulationvelocity collector by on cancellati Partial cbC
exR increases :base intoinjection electron Degenerate
Nakajima, Japanese Journal of Applied Physics, Feb. 1997
More detailed information regarding III-V bipolar transistor physics and design: http://www.ece.ucsb.edu/Faculty/rodwell/publications_and_presentations/publications/2009_may_IPRM_short_course_rodwell.pdf
0
0.5
1
1.5
2
2.5
0 0.5 1 1.5 2 2.5 3 3.5
tau
ec,
ps
inverse current density, 1/J,m2/mA
2
3
4
5
6
7
8
0 2.5 5 7.5 10 12.5
Ccb/A
e (
fF/
m2)
Je (mA/m
2)
-0.2 V
0.0 V
0.2 V
Vcb
= 0.6 V
10-3
10-2
10-1
100
101
102
-0.3 -0.2 -0.1 0 0.1 0.2J(m
A/u
m^2
)V
be-
Fermi-Dirac
Equivalent series
resistance approximation
Boltzmann
Rodwell, Le, Brar, Proc IEEE , February 2008 Jain & Rodwell, IEEE Electron. Dev. Lett., to be published (2011)
c increases :velocitycollector of modulation Voltage
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Space Charge, Kirk Effect, Minimum Ccb charging time
)2/)(/( 2 cdsatcb TqNvJV
)2/)(( 2
min, cTqNV dcb
eff
C
CECE
LOGIC
CLOGICcCLOGICcbv
T
A
A
VV
VIVTAIVC
2/
emitter
collector
min,
collector
2
min,max/)2(2
ccbcbeffTVVvJ
cecbbe VVV )( hence , that Note
Collector capacitance charging time minimized by setting J = Jmax
...if so, charging time scales linearly with collector thickness.
Collector Field Collapse
Collector Depletion Layer Collapse
SiGe HBT InP DHBT
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Space-Charge-Limited Current (Kirk effect) in BJTs
. increased with increases holdKirk thres
.high at increased, ), ( Decreased max
ce
cb
V
JCff
CEEeffective
effectivesat
c
c
ce
satce
TWLA
Av
TR
dI
dV
JV
2
is areaflux current
collector effective thewhere
2
increased with in Increase
2
chargespace
,
0
2
4
6
8
10
12
14
16
0 0.5 1 1.5 2 2.50
5
10
15
20
25
30
35
40
Je (
mA
/m
2)
Vce
(V)
Ajbe
= 0.6 x 4.3 m2
Ib step
= 180 uA
Vcb
= 0 V
Ic (mA
)
Peak ft, f
max
2
3
4
5
6
7
8
0 2.5 5 7.5 10 12.5
Ccb/A
e (
fF/
m2)
Je (mA/m
2)
-0.2 V
0.0 V
0.2 V
Vcb
= 0.6 V
100
200
300
400
500
0 2 4 6 8 10 12
f (
GH
z)
Je (mA/um
2)
f, -0.3 V
cb
0.0 Vcb
-0.2 Vcb
0.2 Vcb
0.6 Vcb
Bipolar Transistor Design eW
bcWcTbT
nbb DT 22
satcc vT 2
ELlength emitter
eex AR /contact
2
through-punchce,operatingce,max cesatc TVVAvI /)(,
contacts
contactsheet
612 AL
W
L
WR
e
bc
e
ebb
e
e
E W
L
L
PT ln1
cccb /TAC
Bipolar Transistor Design: Scaling eW
bcWcTbT
nbb DT 22
satcc vT 2
ELlength emitter cccb /TAC
eex AR /contact
2
through-punchce,operatingce,max cesatc TVVAvI /)(,
contacts
contactsheet
612 AL
W
L
WR
e
bc
e
ebb
e
e
E W
L
L
PT ln1
Breakdown is Never Less Than The Bandgap
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Bipolar Transistors: Scaling Laws, Scaling Roadmap
HBT parameter change
emitter & collector junction widths decrease 4:1
current density (mA/m2) increase 4:1
current density (mA/m) constant
collector depletion thickness decrease 2:1
base thickness decrease 1.4:1
emitter & base contact resistivities decrease 4:1
scaling laws: to double bandwidth
InP HBT scaling roadmap
eW
bcWcTbT
ELlength emitter
150 nm device
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Recent InP HBT Results: Urteaga et al, DRC 2011
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Recent InP HBT Results: Jain et al, DRC 2011
30nm emitter, 30nm base, 100nm collector
0
4
8
12
16
20
24
28
32
109
1010
1011
1012
Gain
(d
B)
Frequency (Hz)
U
H21
f = 480 GHz
fmax
= 1.0 THz
Aje = 0.22 x 2.7 m
2
Ic = 12.1 mA
Je = 20.4 mA/m
2
P = 33.5 mW/m2
Vcb
= 0.7 V
0
5
10
15
20
25
30
0 1 2 3 4 5
Je (
mA
/m
2)
Vce
(V)
P = 30 mW/m2
Ib,step
= 200 A
BV
P = 20 mW/m2
Aje
= 0.22 x 2.7 m2
10-9
10-7
10-5
10-3
10-1
0
5
10
15
20
0 0.2 0.4 0.6 0.8 1
I c, I b
(A
)
Vbe
(V)
Solid line: Vcb
= 0.7V
Dashed: Vcb
= 0V
nc = 1.19
nb = 1.87
Ic
Ib
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Can we make a 1 THz SiGe Bipolar Transistor ?
InP SiGe
emitter 64 18 nm width
2 0.6 m2 access
base 64 18 nm contact width,
2.5 0.7 m2 contact
collector 53 15 nm thick
36 125 mA/m2
2.75 1.3? V, breakdown
f 1000 1000 GHz
fmax 2000 2000 GHz
PAs 1000 1000 GHz
digital 480 480 GHz
(2:1 static divider metric)
Assumes collector junction 3:1 wider than emitter.
Assumes SiGe contacts no wider than junctions
Simple physics clearly drives scaling
transit times, Ccb/Ic
→ thinner layers, higher current density
high power density → narrow junctions
small junctions→ low resistance contacts
Key challenge: Breakdown
15 nm collector → very low breakdown
Also required:
low resistivity Ohmic contacts to Si
very high current densities: heat
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Interconnects
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
kz
III-V MIMIC Interconnects -- Classic Substrate Microstrip
Strong coupling when substrate approaches ~d / 4 thickness
H
W
Thick Substrate
→ low skin loss
Hr
skin 2/1
1
Zero ground
inductance
in package
a
Brass carrier andassembly ground
interconnectsubstrate
IC with backsideground plane & vias
near-zeroground-groundinductance
IC viaseliminateon-wafergroundloops
High via
inductance
12 pH for 100 m substrate -- 7.5 @ 100 GHz
TM substrate
mode coupling
Line spacings must be
~3*(substrate thickness)
lines must be
widely spaced
ground vias must be
widely spaced
all factors require very thin substrates for >100 GHz ICs
→ lapping to ~50 m substrate thickness typical for 100+ GHz
No ground plane
breaks in IC
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
kz
Parasitic slot mode
-V 0V +V
0V
Coplanar Waveguide No ground vias
No need (???) to
thin substrate
Parasitic microstrip mode
+V +V +V
0V
Hard to ground IC
to package
substrate mode coupling
or substrate losses
ground plane breaks → loss of ground integrity
Repairing ground plane with ground straps is effective only in simple ICs
In more complex CPW ICs, ground plane rapidly vanishes
→ common-lead inductance → strong circuit-circuit coupling
40 Gb/s differential TWA modulator driver
note CPW lines, fragmented ground plane
35 GHz master-slave latch in CPW
note fragmented ground plane
175 GHz tuned amplifier in CPW
note fragmented ground plane
poor ground integrity
loss of impedance control
ground bounce
coupling, EMI, oscillation
III-V:
semi-insulating
substrate→ substrate
mode coupling
Silicon
conducting substrate
→ substrate
conductivity losses
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
fewer breaks in ground plane than CPW
III-V MIMIC Interconnects -- Thin-Film Microstrip
narrow line spacing → IC density
... but ground breaks at device placements
still have problem with package grounding
thin dielectrics → narrow lines
→ high line losses
→ low current capability
→ no high-Zo lines
H
W
HW
HZ
r
oo 2/1
~
...need to flip-chip bond
no substrate radiation, no substrate losses
InP 34 GHz PA
(Jon Hacker , Teledyne)
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
No breaks in ground plane
III-V MIMIC Interconnects -- Inverted Thin-Film Microstrip
narrow line spacing → IC density
... no ground breaks at device placements
still have problem with package grounding
thin dielectrics → narrow lines
→ high line losses
→ low current capability
→ no high-Zo lines
...need to flip-chip bond
Some substrate radiation / substrate losses
InP 150 GHz master-slave latch
InP 8 GHz clock rate delta-sigma ADC
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
If It Has Breaks, It Is Not A Ground Plane !
signal line
signal line
ground plane
line 1
“ground”
line 2
“ground”
common-lead inductance
coupling / EMI due to poor ground system integrity is common in high-frequency systems
whether on PC boards
...or on ICs.
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
No clean ground return ? → interconnects can't be modeled !
35 GHz static divider
interconnects have no clear local ground return
interconnect inductance is non-local
interconnect inductance has no compact model
InP 8 GHz clock rate delta-sigma ADC
8 GHz clock-rate delta-sigma ADC
thin-film microstrip wiring
every interconnect can be modeled as microstrip
some interconnects are terminated in their Zo
some interconnects are not terminated
...but ALL are precisely modeled
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
VLSI mm-wave interconnects with ground integrity
negligible breaks in ground plane
narrow line spacing → IC density
negligible ground breaks @ device placements
still have problem with package grounding
thin dielectrics → narrow lines
→ high line losses
→ low current capability
→ no high-Zo lines
...need to flip-chip bond
no substrate radiation, no substrate losses
Also:
Ground plane at *intermediate level* permits
critical signal paths to cross supply lines, or other
interconnects without coupling.
(critical signal line is placed above ground,
other lines and supplies are placed below ground)
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Modeling Interconnects, Passives in Tuned ( RF ) IC's
Interconnects are tuning elements
Narrow bandwidths→ precision is critical
Initial IC simulation uses CAD-systems' library of passive element models.
Final design: 2.5-Dimensional electromagnetic simulation of: lines, junctions, stubs, capacitors, resistors, pads.
150-200 GHz HBT amplifier, Urteaga et al, IEEE JSSCC , Sept. 2003
185GHz HBT amplifier, Urteaga et al, IEEE IMS, May. 2001
1-180GHz HBT amplifier, Agarwal et al, IEEE Trans MTT , Dec.. 1998
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Modeling Interconnects: Digital & Mixed-Signal IC's
longer interconnects: lines terminated in Zo → no reflections.
Shorter interconnects: lines NOT terminated in Zo . But they are *still* transmission-lines. Ignore their effect at your peril !
vl
ZC
ZL
/
,/
,
0
0
If length << wavelength, or line delay<<risetime, short interconnects behave as lumped L and C.
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Design Flow: Digital & Mixed-Signal IC's
All interconnects: thin-film microstrip environment. Continuous ground on one plane.
2.5-D simulations run on representative lines. various widths, various planes same reference (ground) plane.
Simulation data manually fit to CAD line model effective substrate r , effective line-ground spacing.
Width, length, substrate of each line entered on CAD schematic. rapid data entry, rapid simulation.
Resistors and capacitors: 2.5-D simulation→ RLC fit RLC model used in simulation.
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Network analyzer
Calibration...
on-wafer LRL
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
On-Wafer Through-Reflect-Line (TRL) Calibration
Through
Reflect
Line
Device Under Test
225um
reference plane
ΔL ΔL= 90 deg @center frequency. /8<ΔL<3/8
DUT
open short Either open or short needed. Standards need not be accurate. "Open" must have G closer to that of open than that of short. Ports 1 & 2 must be symmetric.
Through line should be long for large probe separation. Minimizes probe-probe coupling. Measurements normalized to the line characteristic impedance.
225um
225um 225um
225um
225um Please see also: http://www.ece.ucsb.edu/Faculty/rodwell/publications_and_presentations/publications/204vg.ppt
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
On-Wafer TRL: Ongoing Issues
High-fmax transistors have very small ( Ccb → Y12 → S12 )
Measurements show small background Y12. ...even with extended reference planes. Particular difficulty in extracting Mason's Unilateral gain. → Corrupts fmax measurement, model extraction.
Measurements normalized to line Z0. ...line impedance is complex at lower frequencies. → must correct for complex Zo in measurements. excessive line resistance degrades precision.
TRL precision greatly impaired if lines couple to substrate; CPW line standards do not work well.
Cj
LjjRZO
)(
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Verification of 140-220GHz TRL Calibration
freq (140.0GHz to 200.0GHz)
S(1
,1)
S(2
,2)
150 160 170 180 190140 200
-0.4
-0.2
0.0
0.2
-0.6
0.4
freq, GHz
dB
(S(2
,1))
dB
(S(1
,2))
Through
freq (140.0GHz to 200.0GHz)
S(1
,1)
S(2
,2)
150 160 170 180 190140 200
-45
-40
-35
-30
-50
-25
freq, GHz
dB
(S(2
,1))
dB
(S(1
,2))
Open Line
freq (140.0GHz to 200.0GHz)
S(1
,1)
S(2
,2)
150 160 170 180 190140 200
-0.8
-0.6
-0.4
-1.0
-0.2
freq, GHz
dB
(S(2
,1))
dB
(S(1
,2))
150 160 170 180 190140 200
-120
-100
-140
-80
freq, GHz
ph
ase
(S(2
,1))
Readout
m10 m10freq=phase(S(2,1))=-91.553
150.0GHz
M. Seo
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
Difficulties with 140-220GHz TRL Calibration
Data on two layouts of 65 nm MOSFET
2E
11
3E
11
4E
11
5E
11
6E
11
7E
11
8E
11
9E
11
1E
11
1E
12
1
2
3
4
5
6
7
8
9
0
10
freq, Hz
MS
GM
AG
_d
B_
ibm
MS
GM
AG
_d
B_
pfg
MA
G/M
SG
, dB
2E
11
3E
11
4E
11
5E
11
6E
11
7E
11
8E
11
9E
11
1E
11
1E
12
2
4
6
8
10
12
14
16
18
0
20
freq, Hz
Um
_ib
m_
dB
Um
_p
fg_
dB
150 160 170 180 190140 200
-15
-10
-5
0
5
10
15
-20
20
freq, GHz
Um
_ib
mU
m_
pfg
U < 0 (!)
10*log10|U| (?)
"Un
ilate
ral g
ain
", d
B
"Un
ilate
ral g
ain
", lin
ea
r
Measured Y-parameters correlate reasonably with expected device model. Small errors in measured 2-port parameters result in large changes in Unilateral gain and Rollet's stability factor; neither measurement is credible.
Y12 appears to be the key problem. IC Sij measurements are fine. Transistor fmax measurements are hard.
12212211
2
1221
4 GGGG
YYU
( K<1 )
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
50+ GHz
Mixed-Signal
& ECL design:
Principles &
Examples
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
High Speed ECL Design
Followers associated with inputs, not outputs Emitters never drive long wires. (instability with capacitive load)
Double termination for least ringing, send or receive termination for moderate-length lines, high-Z loading saves power but kills speed.
Current mirror biasing is more compact. Mirror capacitance→ ringing, instability. Resistors provide follower damping.
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
High Speed ECL Design
Layout: short signal paths at gate centers, bias sources surround core. Inverted thin film microstrip wiring.
Example: 8:1 205 GHz static divider in 256 nm InP HBT.
Key: transistors in on-state operate at Kirk limited-current. → minimizes Ccb/Ic delay.
205 GHz divider, Griffith et al, IEEE CSIC, Oct. 2010
Key: transistors designed for minimum ECL gate delay*, not peak (f, fmax). *hand expression, charge-control analysis
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
mm-wave Op-Amps for Linear Microwave Amplification
0
10
20
30
40
50
108
109
1010
1011
Feedback F
acto
r, d
B
Frequency, Hz
bandwidth loop
increasing
Even for 2 GHz operation,
loop bandwidths must 20-40 GHz.
need very fast transistors
physically small feedback loop;
bias components surround active core.
Griffith et al, IEEE IMS, June. 2011
input power, dBm
ou
tpu
t po
wer
, dB
m
linear response
2-tone intermodulation
increasing feedback
Reduce distortion with strong negative feedback
R. Eden
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
mm-wave Op-Amps for Linear Microwave Amplification
Virtual-ground input stage, Miller feedback
around output stage, makes feedback
insensitive to generator & load impedances.
current-mode analog design
...node impedances kept low
with transimpedance loading
→ high bandwidth
Zt-stage and loop nesting for high gain
even with fast resistor-loaded circuits
...critical for stability in a 50 GHz loop !
(what will the op-amp be connected to ?)
Griffith et al, IEEE IMS, June. 2011
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
mm-wave Op-Amps for Linear Microwave Amplification Griffith et al, IEEE IMS, June. 2011 Griffith et al, IEEE IPRM, May. 2008
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
40 GSample/s Sample/Hold *Design*
master-slave track-hold target 40 GS/s, 6 b (??) 256 nm InP HBT
Saeid Daneshgar
Bias and transmission-line design strongly follows controlled-impedance ECL examples.
layout: ECL buffer. layout: TASTIS.
ECL
ECL TASTIS
ECL
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
RF-IC design
Principles &
Examples
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
RF-IC Design: Simple & Well-Known Procedures
1: (over)stabilize at the design frequency
guided by stability circles
3: Tune remaining port for maximum gain
2: Tune input for Fmin (LNAs) or output for Psat (PAs)
4: Add out-of-band stabilization.
There are many ways to tune port impedances: microstrip lines, MIM capacitors, transformers
Choice guided by tuning losses. No particular preferences.
0
5
10
15
20
25
30
10 100 1000
MS
G/M
AG
, dB
Frequency, GHz
Common base
Common Collector
Common emitter
U
For BJT's, MAG/MSG usually highest for common-base.
→ preferred topology.
Common-base gain is however reduced by:
base (layout) inductance
emitter-collector layout capacitance.
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
parasitic C's and R's represented
by external elements...
Power Amplifier Design (Cripps method)
0
20
40
60
80
100
0 1 2 3 4 5 6 7 8
Curr
ent, m
A
Vce
or Vds
(V)
breakdown
100 mW
200 mW
maxminmaxmax 81 IVVP For maximum saturated output power,
& maximum efficiency
device intrinsic output must see
optimum loadline set by:
breakdown, maximum current, maximum power density.
ammeter monitors intrinsic
junction current
without including
capacitive currents
...(Vcollector-Vemitter )
measures voltage
internal to series parasitic
resistances...
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
3-stage 150-GHz Amplifier; IBM 65 nm CMOS
-20
-15
-10
-5
0
5
10
140 150 160 170 180 190 200
Frequency (GHz)
S21(meas)
S21(sim)
S21 (measured using power sensor)
S11 (meas)
S11 (sim)
S22 (meas)
S22 (sim)
Frequency (GHz)
S21
S22
S11 (meas)
S11 (sim)
-20
-15
-10
-5
0
5
10
140 150 160 170 180 190 200
Frequency (GHz)
S21(meas)
S21(sim)
S21 (measured using power sensor)
S11 (meas)
S11 (sim)
S22 (meas)
S22 (sim)
140 160 180Frequency (GHz)
K-factor
0
1
2
3
140 160 180Frequency (GHz)
Stability
factor (K)
140 160 180Frequency (GHz)
K-factor
0
1
2
3
140 160 180Frequency (GHz)
Stability
factor (K)
S-p
ara
me
ter
(dB
)
-15
-10
-5
0
5
10
-20 -15 -10 -5 0 5
Input power (dBm)
Ou
tpu
t p
ow
er
(dB
m)
0
5
10
15
20
25
Po
wer
Ad
ded
Eff
icie
ncy (
%)
153 GHz
153 GHz
158.4 GHz
158.4 GHz
153 GHz
158.4 GHz
Outp
ut po
we
r (d
Bm
), G
ain
(d
B)
Input power (dBm)
Po
we
r A
dde
d E
ffic
iency (
%)
PAE
Pout
Gain
-15
-10
-5
0
5
10
-20 -15 -10 -5 0 5
Input power (dBm)
Ou
tpu
t p
ow
er (
dB
m)
0
5
10
15
20
25P
ow
er A
dd
ed E
ffic
ien
cy (
%)
153 GHz
153 GHz
158.4 GHz
158.4 GHz
153 GHz
158.4 GHz
153.0GHz
158.4GHz
-15
-10
-5
0
5
10
-20 -15 -10 -5 0 5
Input power (dBm)
Ou
tpu
t p
ow
er (
dB
m)
0
5
10
15
20
25P
ow
er A
dd
ed E
ffic
ien
cy (
%)
153 GHz
153 GHz
158.4 GHz
158.4 GHz
153 GHz
158.4 GHz
153.0GHz
158.4GHz
Acknowledgement: IBM
M. Seo, B. Jagannathan, J. Pekarik, M. Rodwell, IEEE JSSCC, Dec. 2009
Dummy-prefilled microstrip lines
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
220 GHz, 48 mW HBT Power Amplifier
4-cell design: Psat >48 mW @ 220 GHz
schematic of single cell
T. Reed et al, IEEE CSIC, Oct. 2011, to be presented.
8-cell design: not yet fully tested: Psat = ?
Technology: Teledyne 250 nm InP HBT Right-side-up thin-film microstrip wiring. Breaks in ground plane minimized.
Rodwell and Seo, IEEE BCTM Short Course, Oct. 2011, copyright
High Frequency Bipolar IC Design
Digital, mixed-signal, RF-IC (tuned) IC designs----at very high frequencies
Even at 670 GHz, design procedures differ little from that at lower frequencies: classic IC design extends readily to the far-infrared.
Key considerations: Tuned ("RF") ICs Rigorous E&M modeling of all interconnects & passive elements Continuous ground plane → required for predicable interconnect models. Higher frequencies→ close conductor planes→ higher loss, lower current
Key considerations: digital & mixed-signal : Transmission-line modeling of all interconnects Continuous ground plane → required for predicable interconnect models. Unterminated lines within blocks; terminated lines interconnecting blocks. Analog & digital blocks design to naturally interface to 50 or 75.
Next: TMIC designs for 340 GHz, 670 GHz transceivers.