*////////////////////////////////////////////////////////////////////// * (C) National Semiconductor, Inc. * Models developed and under copyright by: * National Semiconductor, Inc. *///////////////////////////////////////////////////////////////////// * Legal Notice: This material is intended for free software support. * The file may be copied, and distributed; however, reselling the * material is illegal *//////////////////////////////////////////////////////////////////// * For ordering or technical information on these models, contact: * National Semiconductor's Customer Response Center * 7:00 A.M.--7:00 P.M. U.S. Central Time * (800) 272-9959 * For Applications support, contact the Internet address: * amps-apps@galaxy.nsc.com * /////////////////////////////////////////////////////////////////// * User Notes: * * 1. Input resistance (Rin) for these JFET op amps is 1TOhm. Rin is * modeled by assuming the option GMIN=1TOhm. If a different (non- * default) GMIN value is needed, users may recalculate as follows: * Rin=(R1||GMIN+R2||GMIN), where R1=R2, * to maintain a consistent Rin model. *////////////////////////////////////////////////////////// *LF356 Monolithic JFET-Input OP-AMP MACRO-MODEL *////////////////////////////////////////////////////////// * * connections: non-inverting input * | inverting input * | | positive power supply * | | | negative power supply * | | | | output * | | | | | * | | | | | .SUBCKT LF356/NS 1 2 99 50 28 * *Features: *Low input bias current = 30pA *Low input offset current = 3pA *High input impedance = 1Tohm *Low input offset voltage = 1mV * ****************INPUT STAGE************** * IOS 2 1 3P *^Input offset current R1 1 3 1E12 R2 3 2 1E12 I1 99 4 100U J1 5 2 4 JX J2 6 7 4 JX R3 5 50 20K R4 6 50 20K *Fp2=20 MHz C4 5 6 1.9894E-13 * ***********COMMON MODE EFFECT*********** * I2 99 50 4.65MA *^Quiescent supply current EOS 7 1 POLY(1) 16 49 3E-3 1 *Input offset voltage.^ R8 99 49 50K R9 49 50 50K * *********OUTPUT VOLTAGE LIMITING******** V2 99 8 2.63 D1 9 8 DX D2 10 9 DX V3 10 50 2.63 * **************SECOND STAGE************** * EH 99 98 99 49 1 F1 9 98 POLY(1) VA3 0 0 0 1.5944E7 G1 98 9 5 6 2E-3 R5 98 9 100MEG VA3 9 11 0 *Fp1=31.96 HZ C3 98 11 49.9798P * *********COMMON-MODE ZERO STAGE********* * G4 98 16 3 49 1E-8 L2 98 17 530.52M R13 17 16 1K * **************OUTPUT STAGE************** * F6 99 50 VA7 1 F5 99 23 VA8 1 D5 21 23 DX VA7 99 21 0 D6 23 99 DX E1 99 26 99 9 1 VA8 26 27 0 R16 27 28 20 V5 28 25 -.25V D4 25 9 DX V4 24 28 -.25V D3 9 24 DX * ***************MODELS USED************** * .MODEL DX D(IS=1E-15) .MODEL JX PJF(BETA=1.25E-5 VTO=-2.00 IS=30E-12) * .ENDS *$