Circuit biasing problem - Page 1
Forum section: electronics / beginners

author: promach
author_rank: Frequent Contributor
timestamp: October 09, 2017, 04:58:51 pm
content: How to bias this differential circuit correctly ?Additional Information:Vdd = 3.3V and This diferential circuit is connected in negative feedback manner to a CMOS inverter.

author: promach
author_rank: Frequent Contributor
timestamp: January 30, 2018, 03:49:15 pm
content: I have created a series, shunt LC bandstop/notch filter.https://github.com/promach/frequency_trap/tree/developmentI am using gEDA withhttps://github.com/noqsi/gnet-spice-noqsignetlist backend and ngspice simulatorHowever, I could not obtain the desired inductor value from the gyrator made up of X1 and GM2 circuit blocks.If all resorts failed, I am thinking of using S-parameter to check the value of the active inductance created from gyrator structure consisting of CMOS inverter and GM2 circuit blocks.frequency_trap.netCode:* gnetlist -L ../.. -g spice-noqsi -o frequency_trap.net frequency_trap.sch* SPICE file generated by spice-noqsi version 20130710* Send requests or bug reports to jpd@noqsi.comCtest X1.IN Vout 1nVd Vdd GND 'SUPPLY'Vs Vss GND 0V.GLOBAL Vdd Vss.INCLUDE CMOS_Inverter.net.INCLUDE Gm2.net.INCLUDE active_inductor.net.PARAM SUPPLY=3.3v.options TEMP=25.MODEL n1 NMOS.MODEL p1 PMOSVtest Vtest GND dc 0+ac 1CL GND Gm2.IN 0.07pFXGm2 Gm2.IN Gm2.OUT GM2X1 X1.IN X1.OUT INV1V_IP_X1 X1.OUT Gm2.IN DC 0VV_IP_Gm2 Gm2.OUT X1.IN DC 0VRs Vtest Vout 1e-6.controlopac lin 10000 100 2000write frequency_trap.rawgnuplot vtest db(vtest)gnuplot vout db(vout)*plot Vtest Vouttran 0.1p 400pplot Vtest X1.IN X1.OUTsetplotplot i(v.xgm2.v_ip3) i(v.xgm2.v_ip4) i(v.xgm2.v_ip5) i(v.xgm2.v_ip6)noise v(Vtest) Vtest lin 100 1 10Gsetplot noise1let noise_figure=db(inoise_spectrum)/2-db(2*sqrt(boltz*290*50))plot noise_figure.endcCMOS_Inverter.netCode:* gnetlist -L ../.. -g spice-noqsi -o CMOS_Inverter.net CMOS_Inverter.sch* SPICE file generated by spice-noqsi version 20130710* Send requests or bug reports to jpd@noqsi.com.subckt INV1 2 1M4 1 2 Vdd Vdd P1 l=0.4u w=3u m=25M1 1 2 Vss Vss N1 l=1.2u w=3u m=25**.ENDSGm2.netCode:* gnetlist -L ../.. -g spice-noqsi -o Gm2.net Gm2.sch* SPICE file generated by spice-noqsi version 20130710* Send requests or bug reports to jpd@noqsi.com.subckt GM2 7 3M4 g3 g3 1 1 P1 l=1u w=3uM3 3 g3 2 2 P1 l=1u w=3uM5 3 5 4 Vss N1 l=1u w=3uM6 g3 7 6 Vss N1 l=1u w=3uI2 8 Vss 40uAI1 9 Vss 40uAVb 5 Vss 1.8VRs 9 8 500k**V_IP6 6 8 DC 0VV_IP5 4 9 DC 0VV_IP4 Vdd 1 DC 0VV_IP3 Vdd 2 DC 0V.ENDSIn ngspice simulation, .OP gave me the following:I am looking at it now. Does anyone have any comment ?Quote

author: Audioguru
author_rank: Super Contributor
timestamp: January 30, 2018, 04:03:37 pm
content: Dark blue wires on a black (negative) background? I will need to wait for darkness at night to see it.Have you ever seen a datasheet with a negative schematic? I haven't.

author: promach
author_rank: Frequent Contributor
timestamp: February 17, 2018, 05:14:09 pm
content: Could you see the circuits now ?

author: ZomBiE80
author_rank: Contributor
timestamp: February 17, 2018, 07:02:06 pm
content: Trying to solve your homeworks here?

author: Wimberleytech
author_rank: Super Contributor
timestamp: February 17, 2018, 08:20:52 pm
content: In your schematic, you have Cs from vtest to gm2 out.In your netlist you have a 1e-6 resistor instead.A cursory glance at your .op output is consistent with the latter.

author: promach
author_rank: Frequent Contributor
timestamp: March 07, 2018, 02:52:30 pm
content: Cs and 1e-6 resistor are in series, so it does no matter.I have edited the schematics screenshots in the first post.You could also see the latest schematics/netlist athttps://github.com/promach/frequency_trap/tree/development

author: promach
author_rank: Frequent Contributor
timestamp: March 07, 2018, 02:55:06 pm
content: I am planning to derive analytically the transconductance transfer function (Iout/Vin) of this Gm2.sch circuit block.I am now going to sketch the small-signal model for Gm2.schCould anyone advise before I start ?

author: Wimberleytech
author_rank: Super Contributor
timestamp: March 07, 2018, 03:48:59 pm
content: Quote from: promach on March 07, 2018, 02:55:06 pmYes, for SS analysis, the two current sources disappear. Split the 500k resistor into two with one in each leg going to ground. The analysis should be quite simple after making these changes.

author: promach
author_rank: Frequent Contributor
timestamp: March 10, 2018, 03:30:13 am
content: Is my small-signal model for Gm2.sch correct other than one minor mistake (Vgs5 should not be zero) ?

author: promach
author_rank: Frequent Contributor
timestamp: March 10, 2018, 03:15:43 pm
content: I am planning to start nodal analysis to formulate analytically the transconductance transfer function (Iout/Vin) tomorrow.However, there are so many nodes in this small-signal circuit. Which nodes should I pick for a start ? I believe I need to use all nodes such that I include all mosfets and resistors into the equation ?Besides, I am going to usehttp://qsapecng.sourceforge.net/index.htmlto verify my own hand calculation. Anyone have any experience/advice regarding this ?

author: rstofer
author_rank: Super Contributor
timestamp: March 10, 2018, 04:20:24 pm
content: Quote from: promach on March 10, 2018, 03:15:43 pmI count 5 nodes and ground which will be your reference. This is not a lot and, yes, you need to include them all.QSapecNG looks very interesting. I tend to use wxMaxima and Matlab but any equation solver will work.

author: promach
author_rank: Frequent Contributor
timestamp: March 10, 2018, 04:39:41 pm
content: QuoteWhere is the fifth node ?

author: rstofer
author_rank: Super Contributor
timestamp: March 10, 2018, 05:34:57 pm
content: I counted the top node and since it is grounded (somehow I missed that), it's not necessary. So, 4 nodes. Pretty easy!Not that I want to solve a 4x4 matrix by hand.

author: Wimberleytech
author_rank: Super Contributor
timestamp: March 10, 2018, 05:56:12 pm
content: Quote from: promach on March 10, 2018, 03:30:13 amYes, it appears correct. My personal style for SS models would draw all gm's such that they all point their controlled current down toward ground and then use Vgs as a control voltage rather than flip it as you did: Vsg.But, that is my style.If you are trying to get the EXACT answer, analyze what you have drawn. If you are happy with reasonable approximations, you can replace gm4Vsg4 with a resistor of value 1/gm4. Then remove rds4 (because it will be MUCH larger than 1/gm4. I think you can also ignore rds6. You cannot ignore rds5, nor Rs/2. But, frankly, if this is your first time to do this analysis, you should probably keep everything in until the last step...then do the simplifications.

author: promach
author_rank: Frequent Contributor
timestamp: March 11, 2018, 12:58:21 am
content: QuoteWhy ?QuoteAre you suggesting T-model ?QuoteI am not planning to simplify before the last step. I am also not going to ignore channel length modulation effect.

author: Wimberleytech
author_rank: Super Contributor
timestamp: March 11, 2018, 01:16:00 am
content: Quote from: promach on March 11, 2018, 12:58:21 amProceed.Let me know when you get your result and I will help if necessary.

author: promach
author_rank: Frequent Contributor
timestamp: March 11, 2018, 04:20:56 am
content: ignoring channel length modulation means deleting ro from the small-sgnal model ?Besides, how do I form equation at node #2 ? I am bit stucked. KCL or KVL ?I only have three equations. Are they sufficient ?

author: Wimberleytech
author_rank: Super Contributor
timestamp: March 11, 2018, 04:35:03 am
content: Quote from: promach on March 11, 2018, 04:20:56 amCorrectQuoteI will take a look tomorrowQuoteNopeAt first glance, there appear to be issue with your equations. I will review carefully tomorrow.

author: Wimberleytech
author_rank: Super Contributor
timestamp: March 11, 2018, 10:14:37 pm
content: Quote from: promach on March 11, 2018, 04:20:56 amYour equations are wrong.You need four equations.Label each node: 1, 2, 3, 4For each node, sum all the currents leaving that node.

author: promach
author_rank: Frequent Contributor
timestamp: March 12, 2018, 12:42:47 am
content: No, I am only left with three nodes since output node is connected to AC ground for transconductance computation.

author: Wimberleytech
author_rank: Super Contributor
timestamp: March 12, 2018, 01:01:18 am
content: Quote from: promach on March 12, 2018, 12:42:47 amOK fine. When you come up with the circuit that you want to analyze and ask for help, let me know.

author: promach
author_rank: Frequent Contributor
timestamp: March 12, 2018, 04:02:58 pm
content: QuoteThe above is comment from someone.What do you guys think ?

author: Wimberleytech
author_rank: Super Contributor
timestamp: March 12, 2018, 06:55:11 pm
content: Quote from: promach on March 12, 2018, 04:02:58 pmRegarding half-differential approximation...yes it can make a difference but generally a second or third-order effect. It does not add complexity to the ss model if you leave the 500k resistor intact--same number of nodes. Probably worth it since you are striving for an exact answer.You gotta clean up your model first though.

author: promach
author_rank: Frequent Contributor
timestamp: March 13, 2018, 12:07:19 pm
content: The circuit is asymmetric differential pair not symmetric one. So we cannot apply virtual ground here and split source-degenerated resistance into halve.https://inst.eecs.berkeley.edu/~ee105/sp07/lectures/SP07-Lecture8-Differential%20Amplifiers-condensed.pdf#page=9

author: promach
author_rank: Frequent Contributor
timestamp: March 25, 2018, 03:34:38 am
content: @WimberleytechWhat do you think ?I guess I need to incorporate mosfet sizing dimension into the transfer function such that I compare my simulation test result against my analytical transconductance transfer function

author: Wimberleytech
author_rank: Super Contributor
timestamp: March 25, 2018, 03:16:38 pm
content: Quote from: promach on March 25, 2018, 03:34:38 amPretty close. Why did you ground Iout? It does not connect to a virtual ground in your system schematic.Re MOSFET sizing, gm is sqrt(2k'IW/L) in the simple model. Rds is (lambda*I)^-1 Depending on the MOSFET model used, it may be hard to hand-calculate an Rds that agrees with the simulation.

author: promach
author_rank: Frequent Contributor
timestamp: March 26, 2018, 01:08:17 am
content: I am using BSIM4 mosfet models as attached below:Code:* NMOS modelcard* The BSIM4 modelcard below was not extracted from any real technologies. It should* not be used for any other purposes except for benchmarking against BSIM team's* standard results using spice3f5.* Authors: ChetanKumar Dabhi, Shivendra Singh Parihar, Navid Paydavosi, Tanvir Morshed,* Darsen Lu, Mohan Dunga, Wenwei Yang, Ali Niknejad, and Chenming Hu..MODEL N1 NMOS+LEVEL = 14+VERSION = 4.81+BINUNIT = 1+PARAMCHK = 1+MOBMOD = 0+CAPMOD = 1+IGCMOD = 1+IGBMOD = 1+GEOMOD = 1+DIOMOD = 1+RDSMOD = 0+RBODYMOD = 0+RGATEMOD = 1+PERMOD = 1+ACNQSMOD = 0+TRNQSMOD = 0+TEMPMOD = 0+MTRLMOD = 1+CVCHARGEMOD = 0+MTRLCOMPATMOD = 1+EOT = 1.8E-9+VDDEOT = 1.5+ADOS = 1.1+BDOS = 1.0+TNOM = 27+TOXE = 1.8E-9+TOXP = 10E-10+TOXM = 1.8E-9+DTOX = 8E-10+EPSROX = 3.9+WINT = 5E-9+LINT = 1E-9+LL = 0+WL = 0+LLN = 1+WLN = 1+LW = 0+WW = 0+LWN = 1+WWN = 1+LWL = 0+WWL = 0+XPART = 1+TOXREF = 1.4E-9+PHIG = 4.05+EPSRGATE = 11.7+SAREF = 5E-6+SBREF = 5E-6+WLOD = 2E-6+KU0 = -4E-6+KVSAT = 0.2+KVTH0 = -2E-8+TKU0 = 0+LLODKU0 = 1.1+WLODKU0 = 1.1+LLODVTH = 1.0+WLODVTH = 1.0+LKU0 = 1E-6+WKU0 = 1E-6+PKU0 = 0+LKVTH0 = 1.1E-6+WKVTH0 = 1.1E-6+PKVTH0 = 0+STK2 = 0+LODK2 = 1.0+STETA0 = 0+LODETA0 = 1.0+LAMBDA = 4E-10+VSAT = 1.1E5+VTL = 2.0E5+XN = 6.0+LC = 5E-9+RNOIA = 0.577+RNOIB = 0.37+LINTNOI = 1E-009+TVOFF = 0+TVFBSDOFF = 0+VTH0 = 0.25+K1 = 0.35+K2 = 0.05+K3 = 0+K3B = 0+W0 = 2.5E-6+DVT0 = 1.8+DVT1 = 0.52+DVT2 = -0.032+DVT0W = 0+DVT1W = 0+DVT2W = 0+DSUB = 2+MINV = 0.05+VOFFL = 0+DVTP0 = 1E-7+MINVCV = 2+VOFFCVL = 0+DVTP1 = 0.05+LPE0 = 5.75E-8+LPEB = 2.3E-10+XJ = 2E-8+NGATE = 5E20+NDEP = 2.8E18+NSD = 1E20+PHIN = 0+CDSC = 0.0002+CDSCB = 0+CDSCD = 0+CIT = 0+VOFF = -0.15+NFACTOR = 1.2+ETA0 = 0.05+ETAB = 0+UC = -3E-11+VFB = -0.55+U0 = 0.032+UA = 5.0E-11+UB = 3.5E-18+A0 = 2+AGS = 1E-20+A1 = 0+A2 = 1+B0 = -1E-20+B1 = 0+KETA = 0.04+DWG = 0+DWB = 0+PCLM = 0.08+PDIBLC1 = 0.028+PDIBLC2 = 0.022+PDIBLCB = -0.005+DROUT = 0.45+PVAG = 1E-20+DELTA = 0.01+PSCBE1 = 8.14E8+PSCBE2 = 5E-8+FPROUT = 0.2+PDITS = 0.2+PDITSD = 0.23+PDITSL = 2.3E6+RSH = 0+RDSW = 50+RSW = 50+RDW = 50+RDSWMIN = 0+RDWMIN = 0+RSWMIN = 0+PRWG = 0+PRWB = 6.8E-11+WR = 1+ALPHA0 = 0.074+ALPHA1 = 0.005+BETA0 = 30+AGIDL = 0.0001+BGIDL = 2.1E9+CGIDL = 0.0001+EGIDL = 0.8+AGISL = 0.0002+BGISL = 2.1E9+CGISL = 0.0002+EGISL = 0.8+AIGBACC = 0.012+BIGBACC = 0.0028+CIGBACC = 0.002+NIGBACC = 1+AIGBINV = 0.014+BIGBINV = 0.004+CIGBINV = 0.004+EIGBINV = 1.1+NIGBINV = 3+AIGC = 0.012+BIGC = 0.0028+CIGC = 0.002+AIGS = 0.012+BIGS = 0.0028+CIGS = 0.002+NIGC = 1+POXEDGE = 1+PIGCD = 1+NTOX = 1+AIGD = 0.01+BIGD = 0.003+CIGD = 0.0015+XRCRG1 = 12+XRCRG2 = 5+CGSO = 6.238E-10+CGDO = 6.238E-10+CGBO = 2.56E-11+CGDL = 2.495E-10+CGSL = 2.495E-10+CKAPPAS = 0.03+CKAPPAD = 0.03+ACDE = 1+MOIN = 15+NOFF = 0.9+VOFFCV = -0.02+KT1 = -0.37+KT1L = 0.0+KT2 = -0.042+UTE = -1.5+UA1 = 1E-9+UB1 = -3.5E-19+UC1 = 0+PRT = 0+AT = 53000+FNOIMOD = 1+TNOIMOD = 0+JSS = 0.0001+JSWS = 1E-11+JSWGS = 1E-10+NJS = 1+IJTHSFWD = 0.01+IJTHSREV = 0.001+BVS = 10+XJBVS = 1+JSD = 0.0001+JSWD = 1E-11+JSWGD = 1E-10+NJD = 1+IJTHDFWD = 0.01+IJTHDREV = 0.001+BVD = 10+XJBVD = 1+PBS = 1+CJS = 0.0005+MJS = 0.5+PBSWS = 1+CJSWS = 5E-10+MJSWS = 0.33+PBSWGS = 1+CJSWGS = 3E-10+MJSWGS = 0.33+PBD = 1+CJD = 0.0005+MJD = 0.5+PBSWD = 1+CJSWD = 5E-10+MJSWD = 0.33+PBSWGD = 1+CJSWGD = 5E-10+MJSWGD = 0.33+TPB = 0.005+TCJ = 0.001+TPBSW = 0.005+TCJSW = 0.001+TPBSWG = 0.005+TCJSWG = 0.001+XTIS = 3+XTID = 3+DMCG = 0+DMCI = 0+DMDG = 0+DMCGT = 0+DWJ = 0+XGW = 0+XGL = 0+RSHG = 0.4+GBMIN = 1E-10+RBPB = 5+RBPD = 15+RBPS = 15+RBDB = 15+RBSB = 15+NGCON = 1+JTSS = 1E-4+JTSD = 1E-4+JTSSWS = 1E-10+JTSSWD = 1E-10+JTSSWGS = 1E-7+JTSSWGD = 1E-7+NJTS = 20.0+NJTSSW = 15+NJTSSWG = 6+VTSS = 10+VTSD = 10+VTSSWS = 10+VTSSWD = 10+NJTSD = 15.0+NJTSSWD = 20+NJTSSWGD = 6+TNJTS = 0.1+TNJTSD = 0.05+VTSSWGS = 2+VTSSWGD = 2+XTSS = 0.02+XTSD = 0.02+XTSSWS = 0.02+XTSSWD = 0.02+XTSSWGS = 0.02+XTSSWGD = 0.02Code:* PMOS modelcard* The BSIM4 modelcard below was not extracted from any real technologies. It should* not be used for any other purposes except for benchmarking against BSIM team's* standard results using spice3f5.* Authors: ChetanKumar Dabhi, Shivendra Singh Parihar, Navid Paydavosi, Tanvir Morshed,* Darsen Lu, Mohan Dunga, Wenwei Yang, Ali Niknejad, and Chenming Hu..MODEL P1 PMOS+LEVEL = 14+VERSION = 4.81+BINUNIT = 1+PARAMCHK = 1+MOBMOD = 0+CAPMOD = 2+IGCMOD = 1+IGBMOD = 1+GEOMOD = 1+DIOMOD = 1+RDSMOD = 0+RBODYMOD = 0+RGATEMOD = 1+PERMOD = 1+ACNQSMOD = 0+TRNQSMOD = 0+TEMPMOD = 0+MTRLMOD = 1+CVCHARGEMOD = 0+MTRLCOMPATMOD = 1+EOT = 1.8E-9+VDDEOT = -1.5+ADOS = 1.1+BDOS = 1.0+TNOM = 27+TOXE = 1.8E-9+TOXP = 10E-10+TOXM = 1.8E-9+DTOX = 8E-10+EPSROX = 3.9+WINT = 5E-9+LINT = 1E-9+LL = 0+WL = 0+LLN = 1+WLN = 1+LW = 0+WW = 0+LWN = 1+WWN = 1+LWL = 0+WWL = 0+XPART = 0+TOXREF = 1.8E-9+PHIG = 4.05+EPSRGATE = 11.7+SAREF = 5E-6+SBREF = 5E-6+WLOD = 2E-6+KU0 = 4E-6+KVSAT = 0.2+KVTH0 = -2E-8+TKU0 = 0.0+LLODKU0 = 1.1+WLODKU0 = 1.1+LLODVTH = 1.0+WLODVTH = 1.0+LKU0 = 1E-6+WKU0 = 1E-6+PKU0 = 0.0+LKVTH0 = 1.1E-6+WKVTH0 = 1.1E-6+PKVTH0 = 0+STK2 = 0+LODK2 = 1.0+STETA0 = 0+LODETA0 = 1.0+LAMBDA = 4E-10+VSAT = 1.1E5+VTL = 2.0E5+XN = 6.0+LC = 5E-9+RNOIA = 0.577+RNOIB = 0.37+LINTNOI = 1E-9+TVOFF = 0+TVFBSDOFF = 0+VTH0 = -0.25+K1 = 0.35+K2 = 0.05+K3 = 0+K3B = 0+W0 = 2.5E-6+DVT0 = 1.8+DVT1 = 0.52+DVT2 = -0.032+DVT0W = 0+DVT1W = 0+DVT2W = 0+DSUB = 2+MINV = 0.05+VOFFL = 0+DVTP0 = 1E-7+MINVCV = 2+VOFFCVL = 0+DVTP1 = 0.05+LPE0 = 5.75E-8+LPEB = 2.3E-10+XJ = 2E-8+NGATE = 5E20+NDEP = 2.8E18+NSD = 1E20+PHIN = 0+CDSC = 0.0002+CDSCB = 0+CDSCD = 0+CIT = 0+VOFF = -0.15+NFACTOR = 1.2+ETA0 = 0.05+ETAB = 0+VFB = 0.55+U0 = 0.0095+UA = 5.0E-11+UB = 3.5E-18+UC = -3E-11+A0 = 2+AGS = 1E-20+A1 = 0+A2 = 1+B0 = -1E-20+B1 = 0+KETA = 0.04+DWG = 0+DWB = 0+PCLM = 0.08+PDIBLC1 = 0.028+PDIBLC2 = 0.022+PDIBLCB = -0.005+DROUT = 0.45+PVAG = 1E-20+DELTA = 0.01+PSCBE1 = 8.14E8+PSCBE2 = 5E-8+FPROUT = 0.2+PDITS = 0.2+PDITSD = 0.23+PDITSL = 2.3E6+RSH = 0+RDSW = 50+RSW = 50+RDW = 50+RDSWMIN = 0+RDWMIN = 0+RSWMIN = 0+PRWG = 0+PRWB = 6.8E-11+WR = 1+ALPHA0 = 0.074+ALPHA1 = 0.005+BETA0 = 30+AGIDL = 0.0002+BGIDL = 2.1E9+CGIDL = 0.0002+EGIDL = 0.8+AGISL = 0.0003+BGISL = 2.5E9+CGISL = 0.0003+EGISL = 0.8+AIGBACC = 0.012+BIGBACC = 0.0028+CIGBACC = 0.002+NIGBACC = 1+AIGBINV = 0.014+BIGBINV = 0.004+CIGBINV = 0.004+EIGBINV = 1.1+NIGBINV = 3+AIGC = 0.012+BIGC = 0.0028+CIGC = 0.002+AIGS = 0.012+BIGS = 0.0028+CIGS = 0.002+NIGC = 1+POXEDGE = 1+PIGCD = 1+NTOX = 1+AIGD = 0.01+BIGD = 0.003+CIGD = 0.0015+XRCRG1 = 12+XRCRG2 = 5+CGSO = 6.238E-10+CGDO = 6.238E-10+CGBO = 2.56E-11+CGDL = 2.495E-10+CGSL = 2.495E-10+CKAPPAS = 0.03+CKAPPAD = 0.03+ACDE = 1+MOIN = 15+NOFF = 0.9+VOFFCV = 0.02+KT1 = -0.37+KT1L = 0.0+KT2 = -0.042+UTE = -1.5+UA1 = 1E-9+UB1 = -3.5E-19+UC1 = 0+PRT = 0+AT = 53000+FNOIMOD = 1+TNOIMOD = 0+JSS = 0.0001+JSWS = 1E-11+JSWGS = 1E-10+NJS = 1+IJTHSFWD = 0.01+IJTHSREV = 0.001+BVS = 10+XJBVS = 1+JSD = 0.0001+JSWD = 1E-11+JSWGD = 1E-10+NJD = 1+IJTHDFWD = 0.01+IJTHDREV = 0.001+BVD = 10+XJBVD = 1+PBS = 1+CJS = 0.0005+MJS = 0.5+PBSWS = 1+CJSWS = 5E-10+MJSWS = 0.33+PBSWGS = 1+CJSWGS = 3E-10+MJSWGS = 0.33+PBD = 1+CJD = 0.0005+MJD = 0.5+PBSWD = 1+CJSWD = 5E-10+MJSWD = 0.33+PBSWGD = 1+CJSWGD = 5E-10+MJSWGD = 0.33+TPB = 0.005+TCJ = 0.001+TPBSW = 0.005+TCJSW = 0.001+TPBSWG = 0.005+TCJSWG = 0.001+XTIS = 3+XTID = 3+DMCG = 0+DMCI = 0+DMDG = 0+DMCGT = 0+DWJ = 0+XGW = 0+XGL = 0+RSHG = 0.4+GBMIN = 1E-10+RBPB = 5+RBPD = 15+RBPS = 15+RBDB = 15+RBSB = 15+NGCON = 1+JTSS = 1E-4+JTSD = 1E-4+JTSSWS = 1E-10+JTSSWD = 1E-10+JTSSWGS = 1E-7+JTSSWGD = 1E-7+NJTS = 20.0+NJTSSW = 15+NJTSSWG = 4+VTSS = 10+VTSD = 10+VTSSWS = 10+VTSSWD = 10+NJTSD = 15.0+NJTSSWD = 20+NJTSSWGD = 6+TNJTS = 0.1+TNJTSD = 0.05+VTSSWGS = 2+VTSSWGD = 2+XTSS = 0.02+XTSD = 0.02+XTSSWS = 0.02+XTSSWD = 0.02+XTSSWGS = 0.02+XTSSWGD = 0.02

author: Wimberleytech
author_rank: Super Contributor
timestamp: March 26, 2018, 02:52:14 am
content: Lambda in the BSIM4 model is different than the lambda in the Shichman-Hodges model.Which SPICE are you using for simulation? Does it output small signal values for each transistor? If so, get your gm's and rds's from the spice output and shove that into your equations.

author: promach
author_rank: Frequent Contributor
timestamp: March 26, 2018, 10:58:46 am
content: QuoteIt is for transconductance purpose. To find the effective transconductance, short the output node to ground.Besides, I am using ngspice. I need to check on this.