LTSpice model LM7805

..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

*$