* 12AT7/ECC81 Triode PSpice Model
* copyright (c) 1998 Mithat Konar -- all rights reserved
* Model used: "Improved VT Models for SPICE Simulations,"
* Norman Koren, Glass Audio 5/96.
* Plate parameters determined by computerized optimization, Jan 29, 1998.
* Plate data from http://www.mclink.it/com/audiomatica/sofia/.
* Interelectrode capacitances are based on data given for RCA 12AT7; however,
* the reliability of the HF characteristics for this model is probably not
* very high. It is likely that that additional complexity will be required
* to better model the HF behavior--including the inclusion of heater terminals
* in order to explicitly incorporate grid, plate, and cathode to heater
* capacitances. And don't forget to add parasitic capacitances of ~0.7 pF
* for adjacent pins and ~0.5 pF for others (see Koren's article) as well as for
* the effects of a shield (if used).
* No guarantees of any kind are made regarding the accuracy or suitability
* of any part of this model. Use at your own risk.
*
* Connections: Plate
* | Grid
* | | Cathode
* | | |
.SUBCKT 12AT7 1 2 3
+ PARAMS: MU=58.5 EX=1.23 KG1=659 KP=267 KVB=1849
+ RGI=2000
+ CCG=2.2P CGP=1.5P CCP=0.45P ;
E1 7 0 VALUE=
+{V(1,3)/KP*LOG(1+EXP(KP*(1/MU+V(2,3)/SQRT(KVB+V(1,3)*V(1,3)))))}
RE1 7 0 1G
G1 1 3 VALUE={ (PWR(V(7),EX)+PWRS(V(7), EX))/KG1 }
RCP 1 3 1G ; TO AVOID FLOATING NODES IN MU-FOLLOWER
C1 2 3 {CCG} ; CATHODE GRID
C2 2 1 {CGP} ; GRID-PLATE
C3 1 3 {CCP} ; CATHODE-PLATE
D3 5 3 DX ; FOR GRID CURRENT
R1 2 5 {RGI} ; FOR GRID CURRENT
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS