Spice models for LM78xx series?

[Mike Rocket J. Squirrel E]

I've Googled my butt off, and haven't come up with anything. I'm
surprised that this venerable series of linear voltage regulators isn't
represented with SPICE subcircuits or models. Any suggestions?

--
Mike "Rocket J Squirrel" Elliott

 

[Chaos Master]

In an arcane spellbook written by the priests, labeled 'Posts of
sci.electronics.cad' I found a message from Mike Rocket J. Squirrel
Elliott[j.michael.elliottAT@REMOVETHEOBVIOUSadelphiaDOT.net]:

I've Googled my butt off, and haven't come up with anything. I'm
surprised that this venerable series of linear voltage regulators isn't
represented with SPICE subcircuits or models. Any suggestions?

CircuitMaker has some models for 7805/7812. You can just download the student
version or the 30-day trial and 'rip' the model libraries. I've done that.

--
'You receive a scroll of signature. It says:'
Chaos MasterŽ - Posting from Porto Alegre - Brazil.
E-mail address is valid. But remove the SPAMTRAP to reply.

 

[Y.Belenky]

..SUBCKT x_LM78XX Input Output Ground PARAMS:
+ Av_feedback=1665, R1_Value=1020
*
* SERIES 3-TERMINAL POSITIVE REGULATOR
*
* Note: This regulator is based on the LM78XX series of
* regulators (also the LM140 and LM340). The model
* will cause some current to flow to Node 0 which
* is not part of the actual voltage regulator circuit.
*
* Band-gap voltage source:
*
* The source is off when Vin<3V and fully on when Vin>3.7V.
* Line regulation and ripple rejection) are set with
* Rreg= 0.5 * dVin/dVbg. The temperature dependence of this
* circuit is a quadratic fit to the following points:
*
* T Vbg(T)/Vbg(nom)
* --- ---------------
* 0 .999
* 37.5 1
* 125 .990
*
* The temperature coefficient of Rbg is set to 2 * the band gap
* temperature coefficient. Tnom is assumed to be 27 deg. C and
* Vnom is 3.7V
*
Vbg 100 0 DC 7.4V
Sbg (100,101),(Input,Ground) Sbg1
Rbg 101 0 1 TC=1.612E-5,-2.255E-6
Ebg (102,0),(Input,Ground) 1
Rreg 102 101 7k
..MODEL Sbg1 VSWITCH (Ron=1 Roff=1MEG Von=3.7 Voff=3)
*
* Feedback stage
*
* Diodes D1,D2 limit the excursion of the amplifier
* outputs to being near the rails. Rfb, Cfb Set the
* corner frequency for roll-off of ripple rejection.

*
* The opamp gain is given by: Av = (Fores/Freg) * (Vout/Vbg)
* where Fores = output impedance corner frequency
* with Cl=0 (typical value about 1MHz)
* Freg = corner frequency in ripple rejection
* (typical value about 600 Hz)
* Vout = regulator output voltage (5,12,15V)
* Vbg = bandgap voltage (3.7V)
*
* Note: Av is constant for all output voltages, but the
* feedback factor changes. If Av=2250, then the
* Av*Feedback factor is as given below:
*
* Vout Av*Feedback factor
* ---- ------------------
* 5 1665
* 12 694
* 15 550
*
Rfb 9 8 1MEG
Cfb 8 Ground 265PF
Eopamp 105 0 VALUE={2250*v(101,0)+Av_feedback*v(Ground,8)}
Vgainf 200 0 {Av_feedback}
Rgainf 200 0 1
*Eopamp 105 0 POLY(3),(101,0),(Ground,8),(200,0) 0 2250 0 0 0 0 0 0 1
Ro 105 106 1k
D1 106 108 Dlim
D2 107 106 Dlim
..MODEL Dlim D (Vj=0.7)
Vl1 102 108 DC 1
Vl2 107 0 DC 1
*
* Quiescent current modelling
*
* Quiescent current is set by Gq, which draws a current
* proportional to the voltage drop across the regulator and
* R1 (temperature coefficient .1%/deg C). R1 must change
* with output voltage as follows: R1 = R1(5v) * Vout/5v.
*
Gq (Input,Ground),(Input,9) 2.0E-5
R1 9 Ground {R1_Value} TC=0.001
*
* Output Stage
*
* Rout is used to set both the low frequency output impedence
* and the load regulation.
*
Q1 Input 5 6 Npn1
Q2 Input 6 7 Npn1 10
..MODEL Npn1 NPN (Bf=50 Is=1E-14)
* Efb Input 4 VALUE={v(Input,Ground)+v(0,106)}
Efb Input 4 POLY(2),(Input,Ground),(0,106) 0 1 1
Rb 4 5 1k TC=0.003
Re 6 7 2k
Rsc 7 9 0.275 TC=1.136E-3,-7.806E-6
Rout 9 Output 0.008
*
* Current Limit
*
Rbcl 7 55 290
Qcl 5 55 9 Npn1
Rcldz 56 55 10k
Dz1 56 Input Dz
..MODEL Dz D (Is=0.05p Rs=3 Bv=7.11 Ibv=0.05u)
..ENDS
*$

Yuri.



Mike Rocket J. Squirrel Elliott wrote:

I've Googled my butt off, and haven't come up with anything. I'm
surprised that this venerable series of linear voltage regulators isn't
represented with SPICE subcircuits or models. Any suggestions?

 

[Mike Rocket J. Squirrel E]

Chaos Master and Y.Belenky:

Thanks!

I've Googled my butt off, and haven't come up with anything. I'm
surprised that this venerable series of linear voltage regulators
isn't represented with SPICE subcircuits or models. Any suggestions?

--
Mike "Rocket J Squirrel" Elliott