006_lstb_stability_diff : Differential Stability analysis
Requires: SmartSpice & Smartview
Minimum Versions: SMARTSPICE 3.17.26.C
This example input deck will allow you to look at the following results.
The .LSTB analysis is used in common and differential mode
- phase_margin(deg)
- gain_margin(db)
- phase_margin_freq(Hz)
- gain_margin_freq(Hz)
- minfreq
- loop_gain_at_min_freq(db)
are calculated, and cx1,cx2 etc. files are written out, which contain gain as a function of frequency, and the CMDMPROBE technique is demonstrated.
Input Files
lstb_fully_diff_opamp_cmdprobe.in
* ADCIN_FULLY_DIFF1.CIR - FULLY DIFFERENTIAL AMPLIFIER ADC DRIVER
******************************************************************
* DIFFERENTIAL SOURCE
.param diffshift=0.00
VPOS 11 10 ac "diffshift" SIN(0V +2VPEAK 1KHZ)
VNEG 12 10 SIN(0V -2VPEAK 1KHZ)
*
* COMMON MODE VOLTAGE
VCM 10 0 DC 0V
*VCM 10 0 SIN(0V 1VPEAK 10KHZ)
*
VREF 5 0 DC 0V
*
R1 12 2 10K
R2 2 3 10K
R3 11 1 10K
R4 1 4 10K
*XOP1 1 2 3 4 5 FULLYDIFF1
vprobe1 v+ 3 0
vprobe2 v- 4 0
XOP1 1 2 v+ v- 5 FULLYDIFF1
c2 2 3 3p
c4 1 4 3p
*
* FULLY DIFF AMP MODEL ********************************
* vip vin vop von vcm_set
.SUBCKT FULLYDIFF1 1 2 3 4 5
* INPUT IMPEDANCE
RIN 1 2 10MEG
* OUTPUT VOLTAGES
EOUTP 3 7 VALUE = { V(1,2) * +100000/2 }
EOUTN 4 7 VALUE = { V(1,2) * -100000/2 }
* COMMON-MODE OUTPUT - SERVO AMP
ECM 7 0 5 6 1e6
RCM1 3 6 1MEG
RCM2 4 6 1MEG
RCMOUT 7 0 1MEG
RCMIN 5 0 1MEG
*
.ENDS
********************************************************
*
* ANALYSIS
*.TRAN 0.01MS 2MS
.lstb dec 30 .1 100meg mode=diff probe=vprobe1,vprobe2
.print ac LSTB(DB)
.option nomod nodeck
*.probe
*.alter
*.lstb dec 30 .1 100meg mode=comm probe=vprobe1,vprobe2
.END
lstb_fully_diff_opamp_cmdprobe.measure.raw0
Title: ADCIN_FULLY_DIFF1.CIR - FULLY DIFFERENTIAL AMPLIFIER ADC DRIVER Input deck file name: V:\examples\smartspice_web\analysis\006_stability_lstb_sim\lstb_fully_diff_opamp_cmdprobe.sp Date: Mon Nov 04 13:47:27 2019 Plotname: Measure Plot Temperature: 0 Sweepvar: phase_margin(deg) Sweepmode: 0 Flags: real padded No. Variables: 6 No. Points: 1 Source: SmartSpice,Platform:0 Version: 4.38.1.R Variables: 0 phase_margin(deg) notype 1 gain_margin(db) notype 2 phase_margin_freq(Hz) notype 3 gain_margin_freq(Hz) notype 4 minfreq notype 5 loop_gain_at_min_freq(db) notype Values: 0 1.797693134862316e+308 1.797693134862316e+308 1.797693134862316e+308 1.797693134862316e+308 1.000000000000000e-001 9.397071853713993e+001
lstb_fully_diff_opamp_cmdprobe.measure.raw1
Title: ADCIN_FULLY_DIFF1.CIR - FULLY DIFFERENTIAL AMPLIFIER ADC DRIVER Input deck file name: /main/alpha/examples/smartspice_web/analysis/006_stability_lstb_sim/lstb_fully_diff_opamp_cmdprobe.sp Date: Thu Jan 17 09:03:57 2013 Plotname: Measure Plot Temperature: 0 Sweepvar: phase_margin(deg) Sweepmode: 0 Flags: real padded No. Variables: 6 No. Points: 1 Source: SmartSpice MultiCore,Platform:0 Version: 3.18.0.R Variables: 0 phase_margin(deg) notype 1 gain_margin(db) notype 2 phase_margin_freq(Hz) notype 3 gain_margin_freq(Hz) notype 4 minfreq notype 5 loop_gain_at_min_freq(db) notype Values: 0 1.797693134862316e+308 1.797693134862316e+308 1.797693134862316e+308 1.797693134862316e+308 1.000000000000000e-01 -9.397089242690984e+01
006_lstb_stability_diff
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Graphics
