Sensitivity Analysis of IBIS-parameters with HSPICE · PDF fileYour Success is Our Goal...
Transcript of Sensitivity Analysis of IBIS-parameters with HSPICE · PDF fileYour Success is Our Goal...
Your Success is Our Goal
Sensitivity Analysis of IBIS-parameters
with HSPICE
DATE 2004IBIS Summit
Meeting Paris 2004
Manfred Maurer
Email: [email protected]
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Overview
• Motivation
• Sensitivity analysis main focus of the design process
• Scaling of the static / dynamic curves of a IBIS model
• Sensitivity analysis with a IBIS-model
• Summary
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Motivation
n Confidence level of the IBIS-Model
n Timing Budget of the design very small
n Application different to the IBIS-model conditions
n Which parameter variation of the IBIS-model have the greatest impact to the time delay on the PCB
n Design robustness has to be evaluated
n Model adjustments to the Golden Waveform
?
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Design Methodologies
n Timing Spreadsheet ( Worst-Case and Statistical)
uSignal integrity / ISI and EMC
n Design Solution Space = (Electrical + Layout + Thermal) Requirements
n Design Guidelines (only) for the actual project
n è Sensitivity Analysis ç
uUncertainty of Reference Voltage (Vth) and Loads
uDifferent TopologiesuThermal considerations
uDetermine Corner conditionsu Initial Monte Carlo Analysis è significance and trend of each variable
uEye Diagrams / fix ISI
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Localization of the actual analysis
Backplane/Cable
can_hIBIS
C1
can_l
Vdd1
GND
CF 150134
C0
S1S2
C3
S3S4
GND
Vdd2
GND
CMOSBuffer
out_1_A
out_1_B
out_2_B
out_2_A
in_1
in_2
in_2
C2
in_1in_2
S5
S6
Rs
TxD
RxD
1
2
3
4
5
Ref_load
Subsystem A
SVVdd1
SVVdd2
can_h IBISModel
C1
can_l
Vdd1
GNDC0
S1 S2
C3
S3 S4
GND
Vdd2
GND
CMOSout_1_A
out_1_B
out_2_B
out_2_A
in_1
in_2
in_2
C2
in_1in_2
S5
S6
Rs
TxD
RxD
Subsystem B
SVVdd1
6
6
Buffer
Backplane/Cable
can_hIBIS
C1
can_l
Vdd1
GND
CF 150134
C0
S1S2
C3
S3S4
GND
Vdd2
GND
CMOSBuffer
out_1_A
out_1_B
out_2_B
out_2_A
in_1
in_2
in_2
C2
in_1in_2
S5
S6
Rs
TxD
RxD
1
2
3
4
5
Ref_load
Subsystem A
SVVdd1
SVVdd2
can_h IBISModel
C1
can_l
Vdd1
GNDC0
S1 S2
C3
S3 S4
GND
Vdd2
GND
CMOSout_1_A
out_1_B
out_2_B
out_2_A
in_1
in_2
in_2
C2
in_1in_2
S5
S6
Rs
TxD
RxD
Subsystem B
SVVdd1
6
6
Buffer
Focus of investigation
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Input-Output Buffer (HSPICE)
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Scaling / tuning possibilities (HSPICE)
Pull upRamp
Pull upV/I
PowerClamp
GNDClamp
Pull downV/I
Pull downRamp
OutputPackage
PowerClamp
GNDClamp
GNDClamp
PowerClamp
Threshold&
EnableLogic
InputPackage
EnablePackage
fwf_tunerwf_tune
fwf_scal
rwf_scal
pd_scal
pu_scal
gc_scal
pc_scal
pc_scal
gc_scal
spu_scal
spd_scal
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HSPICE Syntax of an I/O-Buffer
If ramp=0|1èRAMP adjustment
C_comp distribution between nodes
PU / PD + PC / GC scaling
Rising WF / Falling WF scaling
If power=off è adjustment of the PU/PD curves
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Definition of the Distribution Function
3.09 sigma è 99.8%3.09 sigma è 99.8%
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Timing reference -Scaled and Reference buffer
Sig_out
R_load
Sig_refBuf_ref
TFlight_Time
Tco
Buf_scal
V_term
R_loadV_term
Tramp_20_80
Sig_out
R_load
Sig_refBuf_ref
TFlight_Time
Tco
Buf_scal
V_term
R_loadV_term
Tramp_20_80
èTFlight_Time = Diff TcoèTFlight_Time = Diff Tco
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Scaling of the static curves
IPUscal = pu_scal * I typ
IPUscal = pu_scal * I typ
IPDscal = pd_scal * I typ
IPDscal = pd_scal * I typ
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Wafeform scaling rwf_scal / fwf_scal0.85 / 3 sigma from typical
Ref_Signal typ.Ref_Signal typ.
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rwf_scalè Rising Waveform
IBIS-Model: B24_2 *rwf_scal=3sigma* *typ/min/max*
-1,00E-09
-8,00E-10
-6,00E-10
-4,00E-10
-2,00E-10
0,00E+00
2,00E-10
4,00E-10
6,00E-10
8,00E-10
1,00E-09
0,2 0,4 0,6 0,8 1 1,2 1,4 1,6
r/f_wf_scal
Td_
ram
p20/
80 +
T_f
light
_tim
e (s
)
r_ramp_typ
r_FT_typ
r_FT_minr_ramp_max
r_FT_max
r_ramp_min
Ramp_(20_80)%Ramp_(20_80)%
typtyp
TcoTco
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fwf_scalè Falling Waveform
IBIS-Model: B24_2 *fwf_scal=3sigma* *typ/min/max*
-8,00E-10
-6,00E-10
-4,00E-10
-2,00E-10
0,00E+00
2,00E-10
4,00E-10
6,00E-10
8,00E-10
1,00E-09
0,2 0,4 0,6 0,8 1 1,2 1,4 1,6
f_wf_scal
Td_
ram
p20/
80 +
T_f
light
_tim
e (s
)
f_ramp_typ
f_FT_typ
f_ramp_minf_FT_min
f_ramp_max
f_FT_max
TcoTco
Ramp_(20_80)%Ramp_(20_80)%
typtyp
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Sensitivity analysison a 4 RAM topology
Sig_out
W - Model
SRAM R0
C5e
Sig_refC5e Ref_Load(DS)
l1
lr
lr
lr
l21
l2
lr
SRAM R3
SRAM R2
SRAM R1
l1 30-40mm l2, l21 15-20mmlr 3-13mm
TFlight_TimeTco
Tpd_tot = Tco + T Flight_Time
Sig_out
W - Model
SRAM R0
C5e
Sig_refC5e Ref_Load(DS)
l1
lr
lr
lr
l21
l2
lr
SRAM R3
SRAM R2
SRAM R1
l1 30-40mm l2, l21 15-20mmlr 3-13mm
TFlight_TimeTco
Tpd_tot = Tco + T Flight_Time
pu_scalpu_scal
pd_scalpd_scal
rwf_scalrwf_scal fwf_scalfwf_scal
5% rel_var/ Gauss Distribution5% rel_var/ Gauss Distribution
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Signal Integrity (SI) and ISI è FT
Ref_SignalRef_Signal
RAM_INP.RAM_INP.
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Signal integrity (SI) and ISI (Zoom)
RAM1_INP.RAM1_INP.Ref_SignalRef_Signal
RAM2_INP.RAM2_INP.
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Flight Time of the RAM1&2
Flight Time (rise/fall) RAM1/2 Gauss-distriution
6,00E-10
7,00E-10
8,00E-10
9,00E-10
1,00E-09
1,10E-09
1,20E-09
1,30E-09
1,40E-09
0,97 0,98 0,99 1 1,01 1,02 1,03 1,04
pu/pd_scal + r/fwf_scal
td_F
T(s
) tdr_c_v_r1e
tdf_c_v_r1e
tdr_c_v_r2etdf_c_v_r2e
FT fallFT fall
FT riseFT rise
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Summary
n The analysed model parameter are simulator specific , not IBIS model intrinsic
n The HSPICE B-element è external controlled parameters for model scaling
n With a typical IBIS model è sensitivity analysis are possible
n Robustness of a design can be quantified by the parameters of the B-element
uPu/pd parameter èdirect control of the static current (parameter+10% è +10%I)
uWF-parameter èno fix correlation to the ramp, nor the Tco / FT( IBIS-model specific)
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Kontaktadresse:
Peter MusterI&S GCSchuhstraße 6091052 ErlangenTel: 09131-7-24607Mail: [email protected]
Thank you very much for your attention.
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Contact :
Manfred MaurerI&S IT PS MCH 2Otto-Hahn-Ring 6D-81739 MunichTel: +49 (0) 89 636 47421Mail: [email protected]
Sensitivity Analysis of IBIS-parameters
with HSPICE