EE122 Prelab 6 Differential Amplifier *_________________________________________________________________________ * by Rafael Betancourt * 5/10/92 created * 8/11/92 revised *_________________________________________________________________________ * * Supplies *_________________________________________________________________________ * Vcc cc 0 +12 Vee ee 0 -12 *_________________________________________________________________________ * * Differential Pair *_________________________________________________________________________ * R1 cc cQ1 ??? R2 p1 cQ2 ??? Rp1 cc p1 ??? *Rp1 cc p1 rmod 1 ; item #1, use with .DC card to sweep P1 Q1 cQ1 bQ1 cQ4 n3565 Q2 cQ2 bQ2 cQ4 n3565 *Q1 cQ1 bQ1 cQ4 n3565A ; item #2 *Q2 cQ2 bQ2 cQ4 n3565B ; item #2 *_________________________________________________________________________ * * Tail Current Source *_________________________________________________________________________ * Q4 cQ4 d1 eQ4 n3904 R3 eQ4 ee ??? *_________________________________________________________________________ * * Common Emitter Second Stage *_________________________________________________________________________ * Q3 out cQ2 cc n3906 Q5 out d1 eQ5 n3904 R4 eQ5 ee ??? Rl out 0 100k *C4 cQ2 out ??? ; Comp. Cap. use fu=100Hz for items #4 & #5 *_________________________________________________________________________ * * Bias Reference Source *_________________________________________________________________________ * Vd1 d1 ee 1.4 ; use instead of R5, D1, D2 *R5 cc d1 4.7k *D1 d1 d2 n4148 *D2 d2 ee n4148 *_________________________________________________________________________ * * Input Circuit *_________________________________________________________________________ * *Vs ins 0 AC 1 ; items #3, #4, #5 *Rs ins in+ 50 R6 0 bQ1 47 ; items #1, #2 DC bias R7 0 bQ2 47 *R6 0 bQ1 47 ; items #3, #4 Open Loop Gain & BW *R7 in+ bQ2 47 *R6 in- bQ1 47 ; item #5 AC response with Feedback *R7 in+ bQ2 47 *R6 in+ bQ1 47 ; Nerd Bonus Common Mode Gain *R7 in+ bQ2 47 *_________________________________________________________________________ * * Feedback Loop, item #5 : Set Rg for gains of 1, 10, and 1000 *_________________________________________________________________________ * *Rg in- cc1 ??? *C1 cc1 0 1000uF *Rf in- out 100k *_________________________________________________________________________ * * Device models *_________________________________________________________________________ * .model n4148 d (is=1E-12) .model n3565 npn (Bf=150 Is=1.0E-14 Va=100 Tf=0.9n Cje=5pF Cjc=5pF) .model n3565A npn (Bf=200 Is=1.2E-14 Va=100 Tf=0.9n Cje=5pF Cjc=5pF) .model n3565B npn (Bf=100 Is=0.8E-14 Va=100 Tf=0.9n Cje=5pF Cjc=5pF) .model n3904 npn (Bf=100 Is=0.29E-14 Va=100 Tf=0.6n Cje=4pF Cjc=3.6pF) .model n3906 pnp (Bf= 50 Is=0.29E-14 Va= 50 Tf=0.6n Cje=6pF Cjc=6.7pF) .model rmod res (r=1) *_________________________________________________________________________ * * Analysis *_________________________________________________________________________ * *.DC res rmod(r) 1 1k 10 ; item #1, #2 .OP .AC DEC 10 1 100MEG .option post .end