From 825fd5668026f70071c7a5eef277b0bf5c8f02d2 Mon Sep 17 00:00:00 2001 From: Maximiliano Curia Date: Wed, 4 Jan 2012 00:00:53 +0100 Subject: Import oregano_0.70.orig.tar.gz [dgit import orig oregano_0.70.orig.tar.gz] --- help/C/oregano.xml | 447 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 447 insertions(+) create mode 100644 help/C/oregano.xml (limited to 'help/C/oregano.xml') diff --git a/help/C/oregano.xml b/help/C/oregano.xml new file mode 100644 index 0000000..5d36977 --- /dev/null +++ b/help/C/oregano.xml @@ -0,0 +1,447 @@ + + + + + + Oregano"> +]> +
+ + <application>Oregano</application> User's Guide + + 2009 + Marc Lorber + + + 20032004 + LUGFi + + + 199920012002 + Richard Hult + + + LUGFI + + + + + Marc Lorber + +
Lorber.Marc@wanadoo.fr
+ + + Ricardo Markiewicz + +
rmarkie@fi.uba.ar
+ + + + + + Oregano Manual V 0.1 + 2009 + + Marc Lorber + + + + Oregano Manual V 0 + 2004 + + Ricardo Markiewicz + + + + + + Oregano is a tool for schematic capture and simulation + of electronic circuits. It simplifes design of simple circuits + by letting the user draw the circuit and then simulate its + electrical characteristics. + + This document is mostly meant to be an introduction + for someone who already is familiar with circuit simulation + and wants to try out Oregano. + + + + &legal; + + + + Feedback + To report a bug or make a suggestion regarding the + Oregano application or + this manual, follow the directions in the Oregano Feedback Page. + + + + + + + + + + <emphasis>Spice</emphasis>: circuit simulation program + Spice is a general-purpose circuit simulation program for nonlinear DC, nonlinear + transient, and linear AC analyses. Circuits may contain resistors, capacitors, inductors, + mutual inductors, independent voltage and current sources, four types of dependent sources, + lossless and lossy transmission lines (two separate implementations), switches, uniform + distributed RC lines, and the five most common semiconductor devices: diodes, BJTs, JFETs, + MESFETs, and MOSFETs. + Spice has built-in models for the semiconductor devices, and the user need specify + only the pertinent model parameter values. The model for the BJT is based on the + integral-charge model of Gummel and Poon; however, if the Gummel-Poon parameters are not + specified, the model reduces to the simpler Ebers-Moll model. In either case, charge-storage + effects, ohmic resistances, and a current-dependent output conductance may be included. The + diode model can be used for either junction diodes or Schottky barrier diodes. The JFET model + is based on the FET model of Shichman and Hodges. Six MOSFET models are implemented: MOS1 + is described by a square-law I-V characteristic, MOS2 [1] is an analytical model, while MOS3 + [1] is a semi-empirical model; MOS6 [2] is a simple analytic model accurate in the short-channel + region; MOS4 [3, 4] and MOS5 [5] are the BSIM (Berkeley Short-channel IGFET Model) and BSIM2. + MOS2, MOS3, and MOS4 include second-order effects such as channel-length modulation, + subthreshold conduction, scattering-limited velocity saturation, small-size effects, and + charge-controlled capacitances. + + Types of analyses + + + DC analyses + The DC analysis portion of Spice (.DC) determines the DC operating point of the circuit + with inductors shorted and capacitors opened. The DC analysis options are specified on the .DC, + .TF, and .OP control lines. A DC analysis is automatically performed prior to a transient analysis + to determine the transient initial conditions, and prior to an AC small-signal analysis to determine + the linearized, small-signal models for nonlinear devices. If requested, the DC small-signal value + of a transfer function (ratio of output variable to input source), input resistance, and output + resistance is also computed as a part of the dc solution. The DC analysis can also be used to + generate dc transfer curves: a specified independent voltage or current source is stepped over a + user-specified range and the DC output variables are stored for each sequential source value. + + + + + AC Small-Signal Analysis + The AC small-signal portion of Spice (.AC) computes the AC output variables as a function of + frequency. The program first computes the DC operating point of the circuit and determines linearized, + small-signal models for all of the nonlinear devices in the circuit. The resultant linear circuit is + then analyzed over a user-specified range of frequencies. The desired output of an AC small-signal + analysis is usually a transfer function (voltage gain, trans-impedance, etc). If the circuit has only + one AC input, it is convenient to set that input to unity and zero phase, so that output variables + have the same value as the transfer function of the output variable with respect to the input. + + + + Transient analysis + The transient analysis portion of Spice (.TRAN) computes the transient output variables as a + function of time over a user-specified time interval. The initial conditions are automatically + determined by a DC analysis. All sources which are not time dependent (for example, power supplies) + are set to their DC value. The transient time interval is specified on a .TRAN control line. + + + + Pole-Zero Analysis + The pole-zero analysis portion of Spice (.PZ) computes the poles and/or zeros in the small-signal + AC transfer function. The program first computes the DC operating point and then determines the linearized, + small-signal models for all the nonlinear devices in the circuit. This circuit is then used to find the + poles and zeros of the transfer function. + + Two types of transfer functions are allowed: one of the form (output voltage)/(input voltage) and + the other of the form (output voltage)/(input current). These two types of transfer functions cover all + the cases and one can find the poles/zeros of functions like input/output impedance and voltage gain. + The input and output ports are specified as two pairs of nodes. + + The pole-zero analysis works with resistors, capacitors, inductors, linear-controlled sources, + independent sources, BJTs, MOSFETs, JFETs and diodes. Transmission lines are not supported. + + The method used in the analysis is a sub-optimal numerical search. For large circuits it may + take a considerable time or fail to find all poles and zeros. For some circuits, the method becomes + "lost" and finds an excessive number of poles or zeros. + + + + + Small-Signal Distortion Analysis + The distortion analysis portion of Spice (.DISTO) computes steady-state harmonic and + intermodulation products for small input signal magnitudes. If signals of a single frequency are + specified as the input to the circuit, the complex values of the second and third harmonics are + determined at every point in the circuit. If there are signals of two frequencies input to the circuit, + the analysis finds out the complex values of the circuit variables at the sum and difference of the input + frequencies, and at the difference of the smaller frequency from the second harmonic of the larger + frequency. + Distortion analysis is supported for the following nonlinear devices: diodes (DIO), BJT, JFET, + MOSFETs (levels 1, 2, 3, 4/BSIM1, 5/BSIM2, and 6) and MESFETS. All linear devices are automatically + supported by distortion analysis. If there are switches present in the circuit, the analysis continues + to be accurate provided the switches do not change state under the small excitations used for distortion + calculations. + + + + Sensitivity Analysis + Spice will calculate (.SENS) either the DC operating-point sensitivity or the AC small-signal + sensitivity of an output variable with respect to all circuit variables, including model parameters. + Spice calculates the difference in an output variable (either a node voltage or a branch current) + by perturbing each parameter of each device independently. Since the method is a numerical approximation, + the results may demonstrate second order affects in highly sensitive parameters, or may fail to show very + low but non-zero sensitivity. Further, since each variable is perturb by a small fraction of its value, + zero-valued parameters are not analyized (this has the benefit of reducing what is usually a very large + amount of data). + + + + Noise Analysis + The noise analysis portion of Spice (.NOISE) does analysis device-generated noise for the given + circuit. When provided with an input source and an output port, the analysis calculates the noise + contributions of each device (and each noise generator within the device) to the output port voltage. + It also calculates the input noise to the circuit, equivalent to the output noise referred to the specified + input source. This is done for every frequency point in a specified range - the calculated value of the noise + corresponds to the spectral density of the circuit variable viewed as a stationary gaussian stochastic + process. + After calculating the spectral densities, noise analysis integrates these values over the specified + frequency range to arrive at the total noise voltage/current (over this frequency range). This calculated + value corresponds to the variance of the circuit variable viewed as a stationary gaussian process. + + + + + + Analyses at different temperatures + All input data for Spice is assumed to have been measured at a nominal temperature of 27°C, which + can be changed by use of the TNOM parameter on the .OPTIONS control line. This value can further be + overridden for any device which models temperature effects by specifying the TNOM parameter on the model + itself. The circuit simulation is performed at a temperature of 27°C, unless overridden by a TEMP parameter + on the .OPTIONS control line. Individual instances may further override the circuit temperature through + the specification of a TEMP parameter on the instance. + + Temperature appears explicitly in the exponential terms of the BJT and diode model paras. In + addition, saturation currents have a built-in temperature dependence. The temperature dependence of the + saturation current in the BJT models is determined by: + +
+ IS(T1) = IS(T0)*(T1XTI/T0) + *exp(q*EG*(T1*T0)/(k*T1-T0)) +
+ where k is Boltzmann's constant, q is the electronic charge, Eg is the energy gap which is a model + parameter, and XTI is the saturation current temperature exponent (also a model parameter, and usually + equal to 3). + + The temperature dependence of forward and reverse beta is according to the formula: + + B(T1) = B(T0)* T1XTB/T0 + 
+                              XTI
+                          |T |        | E q(T  T )|
+                            1            g   1  0
+          I (T ) = I (T ) |--|     exp|-----------|
+           S  1     S  0
+                          |T |        |k (T  - T )|
+                            0              1    0
+
+ COUCOUCOUCOUCOIU + + + x + = + + + -b + ± + + + b2 + - + 4ac + + + + 2⁢a + + + + COUCOUCOUCOUCOIU + + where T1 and T0 are in kelvin, and XTB is a user-supplied model parameter. Temperature effects + on beta are carried out by appropriate adjustment to the values of BF, ISE, BR , and ISC (Spice model + parameters BF, ISE, BR, and ISC, respectively). + + Temperature dependence of the saturation current in the junction diode model is determined by: + IS(T1) = IS(T0)*(T1XTI/T0) + *exp(q*EG*(T1*T0)/(k*T1-T0)) + + 
+                                      XTB
+                                  |T |
+                                    1
+                    B(T ) = B(T ) |--|
+                       1       0
+                                  |T |
+                                    0
+
+ + + where N is the emission coefficient, which is a model parameter, and the other symbols have + the same meaning as above. Note that for Schottky barrier diodes, the value of the saturation current + temperature exponent, XTI, is usually 2. + + Temperature appears explicitly in the value of junction potential, U (in Spice PHI), for all the + device models. The temperature dependence is determined by: + + + 
+                             XTI
+                             ---
+                              N
+                         |T |        |  E q(T  T ) |
+                           1             g   1  0
+         I (T ) = I (T ) |--|     exp|-------------|
+          S  1     S  0
+                         |T |        |N k (T  - T )|
+                           0                1    0
+
+ where k is Boltzmann's constant, q is the electronic charge, Na is the acceptor impurity density, + Nd is the donor impurity density, Ni is the intrinsic carrier concentration, and Eg is the energy gap. + + Temperature appears explicitly in the value of surface mobility, M0 (or UO), for the MOSFET model. + The temperature dependence is determined by: + + R(T) = R(T0) [1 + TC1 (T - T0 ) + TC2 (T - T0)2] + + 
+
+                                   | N N   |
+                                      a d
+                          kT       |------ |
+                   U(T) = --  log        2
+                           q     e |N (T)  |
+                                     i
+
+ + + The effects of temperature on resistors is modeled by the formula: + + IS(T1) = IS(T0)*(T1XTI/T0) + *exp(q*EG*(T1*T0)/(k*T1-T0)) + 
+                                M (T )
+                                 0  0
+                       M (T) = -------
+                        0          1.5
+                               | T|
+                               |--|
+                               |T |
+                                 0
+
+ + + + where T is the circuit temperature, T0 is the nominal temperature, and TC1 and TC2 are the first- + and second-order temperature coefficients. + + + + + Convergence + Both dc and transient solutions are obtained by an iterative process which is terminated when both + of the following conditions hold: + + + + The nonlinear branch currents converge to within a tolerance of 0.1% or 1 picoamp (1.0-12A), whichever + is larger. + The node voltages converge to within a tolerance of 0.1% or 1 microvolt (1.0-6V), whichever is larger. + + + Although the algorithm used in Spice has been found to be very reliable, in some cases it fails to + converge to a solution. When this failure occurs, the program terminates the job. + + Failure to converge in dc analysis is usually due to an error in specifying circuit connections, + element values, or model parameter values. Regenerative switching circuits or circuits with positive feedback + probably will not converge in the dc analysis unless the OFF option is used for some of the devices in the + feedback path, or the .NODESET control line is used to force the circuit to converge to the desired state. + + + + + + + + Getting Started with Oregano + + When you first start &app;, you will be presented to an + empty sheet, where you can place circuit components and connect + them with wires. To place a component, also known as 'part', + first select one in the part browser on the right hand side of + the application window. Then press the 'Place' button, or double-click + the selected part. You can also drag the part preview and drop it + on the sheet. + +
+ &app; oregano: main window + + +
+ + When you have some parts placed on the sheet, you can start + connecting them with wires. Select the wire tool on the toolbar, + and click on the sheet where you want the wire to start. Then + click where you want to fixate the wire. + + Make sure you connect at least one ground node to the circuit, + as this is neccessary to perform a simulation. + + + + + Editing the Circuit + + There are a few accelerator keys that can help editing the + circuit: + + + Ctrl-ASelect all objects on the sheet + + + Ctrl-Shift-ADeselect all objects + + + rRotate the selected objects 90 degrees clockwise + + + <Del>Delete the selected objects + + + lPlace the currently selected part + + + + + Parts and wires can be selected by clicking on them, and by holding the + Shift-key while clicking, you can select multiple parts and wires. You can + also select objects by 'rubber-banding': hold down the mouse button while dragging + the pointer over the objects that you wish to select. + + + + + Simulation + + When you have a circuit and wish to run a simulation, either press the + simulate button on the toolbar or select + Tools->Simulation. + The simulation then starts and you can follow the progress on the dialog box + that pops up. + + If you want to change the simulation parameters, select + Settings->Simulation Settings. + + + +
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