Re: [Ngspice-users] corresponding model for OTA device in LTSPICE netlist

[Holger V. <hol...@un...>]

I have found an LTSPICE OTA replacement:

Xota 2 COM 2 2 2 2 N004 2 ng_ota g=100u Iout=10u Ref=1.259 Vhigh=10 Vlow=-10
*A1 2 COM 2 2 2 2 N004 2 OTA g=100u Iout=10u Ref=1.259 Vhigh=10 Vlow=-10

* OTA
* http://ltwiki.org/?title=Undocumented_LTspice#OTA
* in1- in1+ in2+ in2- nc nc out com
.subckt ng_ota n1 n2 n3 n4 n5 n6 n7 n8 g=1 Iout=10u Ref=0 Vhigh=2 
Vlow=-2 Rclamp=1
* the formula from wiki is not correct concerning V(n3,n4)
Biraw viraw 0 V = g * ( Ref - V(n1,n2) ) $ * (V(n3,n4))
Bout n7 n8 I = tanh(V(viraw)/'Iout')*'Iout'
Vh hi 0 'Vhigh'
Vl lo 0 'Vlow'
* clamp to rails with Rclamp and diodes
Rclamp1 nhi hi 'Rclamp'
Dclamp1 n7 nhi dio
Rclamp2 nlo lo 'Rclamp'
Dclamp2 nlo n7 dio
.model dio D
.ends