A Precision Clamping Circuit ** Circuit Description ** * op-amp subcircuit .subckt uA741 1 2 3 4 5 * connections: | | | | | * | | | | | * non-inverting input | | | | * inverting input | | | * positive power supply | | * negative power supply | * output * * c1 11 12 8.661E-12 c2 6 7 30.00E-12 dc 5 53 dx de 54 5 dx dlp 90 91 dx dln 92 90 dx dp 4 3 dx egnd 99 0 poly(2) (3,0) (4,0) 0 .5 .5 fb 7 99 poly(5) vb vc ve vlp vln 0 10.61E6 -10E6 10E6 10E6 -10E6 ga 6 0 11 12 188.5E-6 gcm 0 6 10 99 5.961E-9 iee 10 4 dc 15.16E-6 hlim 90 0 vlim 1K q1 11 2 13 qx q2 12 1 14 qx r2 6 9 100.0E3 rc1 3 11 5.305E3 rc2 3 12 5.305E3 re1 13 10 1.836E3 re2 14 10 1.836E3 ree 10 99 13.19E6 ro1 8 5 50 ro2 7 99 100 rp 3 4 18.16E3 vb 9 0 dc 0 vc 3 53 dc 1 ve 54 4 dc 1 vlim 7 8 dc 0 vlp 91 0 dc 40 vln 0 92 dc 40 .model dx D(Is=800.0E-18 Rs=1) .model qx NPN(Is=800.0E-18 Bf=93.75) .ends uA741 ** Main Circuit ** * power supplies Vcc 4 0 DC +15V Vee 5 0 DC -15V * input signal source Vi 1 0 SIN ( 0 5V 1kHz ) * limiter circuit Xopamp1 0 2 4 5 3 uA741 D1 3 2 D1N4148 C 1 2 1uF IC=0V * model statements .model D1N4148 D (Is=0.1p Rs=16 CJO=2p Tt=12n Bv=100 Ibv=0.1p) ** Analysis Requests ** .OPTIONS itl5=0 .TRAN 50us 4ms 0s 50us UIC ** Output Requests ** .PLOT TRAN V(3) V(1) .probe .end