v 20110115 2 C 40000 40000 0 0 0 title-B.sym C 43700 45000 1 0 0 diode.sym { T 44100 45600 5 10 0 0 0 0 1 device=DIODE T 44000 45500 5 10 0 0 0 0 1 footprint=DO-35 } C 44600 45000 1 0 0 diode.sym { T 45000 45600 5 10 0 0 0 0 1 device=DIODE T 44900 45500 5 10 0 0 0 0 1 footprint=DO-35 } C 45500 45000 1 0 0 diode.sym { T 45900 45600 5 10 0 0 0 0 1 device=DIODE T 45800 45500 5 10 0 0 0 0 1 footprint=DO-35 } C 47500 44200 1 90 0 cap-mylar.sym { T 46800 44400 5 10 0 0 90 0 1 device=CAPACITOR T 47000 44400 5 10 0 1 90 0 1 refdes=C? T 46600 44400 5 10 0 0 90 0 1 symversion=0.1 } C 41500 46300 1 0 0 vcc.sym C 49800 43100 1 0 1 npn-2.sym { T 49200 43600 5 10 0 0 0 6 1 device=NPN_TRANSISTOR T 49200 43600 5 10 0 1 0 6 1 refdes=Q? } C 49200 42800 1 0 0 gnd.sym N 44600 45100 44600 45200 4 N 45500 45100 45500 45200 4 C 42400 44500 1 180 1 opa.sym { T 42600 42200 5 10 0 0 180 6 1 device=DUAL_OPAMP T 42600 42400 5 10 0 0 180 6 1 footprint=DIL 14 300 T 42600 42000 5 10 0 0 180 6 1 symversion=0.2 } C 44800 44200 1 90 0 cap-mylar.sym { T 44100 44400 5 10 0 0 90 0 1 device=CAPACITOR T 44300 44400 5 10 0 1 90 0 1 refdes=C? T 43900 44400 5 10 0 0 90 0 1 symversion=0.1 } C 45700 44200 1 90 0 cap-mylar.sym { T 45000 44400 5 10 0 0 90 0 1 device=CAPACITOR T 45200 44400 5 10 0 1 90 0 1 refdes=C? T 44800 44400 5 10 0 0 90 0 1 symversion=0.1 } C 41800 45400 1 90 0 resistor.sym { T 41400 45700 5 10 0 0 90 0 1 device=RESISTOR T 41600 46000 5 10 0 1 180 0 1 refdes=R? T 41800 45400 5 10 0 1 90 0 1 footprint=R025DOUBLE T 41800 45800 5 10 1 1 0 0 1 value=22K } C 41800 44500 1 90 0 resistor.sym { T 41400 44800 5 10 0 0 90 0 1 device=RESISTOR T 41600 45100 5 10 0 1 180 0 1 refdes=R? T 41800 44500 5 10 0 1 90 0 1 footprint=R025DOUBLE T 41800 44900 5 10 1 1 0 0 1 value=100K } C 41600 44000 1 0 0 gnd.sym T 41000 50100 9 10 1 0 0 0 3 EIDAC needs NPN due to DAC ground reference constraint. This means voltage bias goes near VCC -> requires rail2rail opamp. T 41000 48700 9 10 1 0 0 0 2 Low impedance point at VG. bottom diode chain carries VG + AC signal. High impedance point at bias current source ideal for AC signal pickup C 42400 43300 1 0 0 resistor.sym { T 42700 43700 5 10 0 0 0 0 1 device=RESISTOR T 43000 43500 5 10 0 1 90 0 1 refdes=R? T 42400 43300 5 10 0 1 0 0 1 footprint=R025DOUBLE T 42600 43100 5 10 1 1 0 0 1 value=100K } C 42400 42500 1 0 0 resistor.sym { T 42700 42900 5 10 0 0 0 0 1 device=RESISTOR T 43000 42700 5 10 0 1 90 0 1 refdes=R? T 42400 42500 5 10 0 1 0 0 1 footprint=R025DOUBLE T 42600 42300 5 10 1 1 0 0 1 value=3K-13K } C 46400 45000 1 0 0 diode.sym { T 46800 45600 5 10 0 0 0 0 1 device=DIODE T 46700 45500 5 10 0 0 0 0 1 footprint=DO-35 } C 46600 44200 1 90 0 cap-mylar.sym { T 45900 44400 5 10 0 0 90 0 1 device=CAPACITOR T 46100 44400 5 10 0 1 90 0 1 refdes=C? T 45700 44400 5 10 0 0 90 0 1 symversion=0.1 } N 47300 45100 47300 45200 4 N 46400 45100 46400 45200 4 C 41000 45300 1 270 0 cap-elco.sym { T 41700 45100 5 10 0 0 270 0 1 device=POLARIZED_CAPACITOR T 41700 45100 5 10 0 0 270 0 1 footprint=ELCO T 41500 45100 5 10 0 1 270 0 1 refdes=C? T 41900 45100 5 10 0 0 270 0 1 symversion=0.1 } N 41700 44300 41700 44500 4 N 41200 44400 41700 44400 4 N 41200 45300 41200 45400 4 N 43400 43400 43400 44100 4 C 42400 42500 1 0 1 resistor.sym { T 42100 42900 5 10 0 0 0 6 1 device=RESISTOR T 41800 42700 5 10 0 1 90 2 1 refdes=R? T 42400 42500 5 10 0 1 0 6 1 footprint=R025DOUBLE T 42100 42800 5 10 1 1 0 6 1 value=1M } C 40700 42700 1 180 1 input-1.sym { T 40800 42400 5 10 1 1 180 6 1 device=SAW } B 48900 42500 2200 3000 3 0 0 0 -1 -1 0 -1 -1 -1 -1 -1 T 50300 45100 9 10 1 0 0 0 1 EIDAC T 50300 41000 9 10 1 0 0 0 1 DIODE LADDER FILTER - JUNE 2014 T 53900 40100 9 10 1 0 0 0 1 Tom Schouten T 41800 42100 9 10 1 0 0 6 1 SAW has DC (OK?) C 50500 43100 1 0 1 npn-2.sym { T 49900 43600 5 10 0 0 0 6 1 device=NPN_TRANSISTOR T 49900 43600 5 10 0 1 0 6 1 refdes=Q? } C 49900 42800 1 0 0 gnd.sym N 49800 43600 50500 43600 4 N 47300 45200 50000 45200 4 N 50000 45200 50000 44100 4 C 43700 43900 1 0 0 diode.sym { T 44100 44500 5 10 0 0 0 0 1 device=DIODE T 44000 44400 5 10 0 0 0 0 1 footprint=DO-35 } C 44600 43900 1 0 0 diode.sym { T 45000 44500 5 10 0 0 0 0 1 device=DIODE T 44900 44400 5 10 0 0 0 0 1 footprint=DO-35 } C 45500 43900 1 0 0 diode.sym { T 45900 44500 5 10 0 0 0 0 1 device=DIODE T 45800 44400 5 10 0 0 0 0 1 footprint=DO-35 } C 46400 43900 1 0 0 diode.sym { T 46800 44500 5 10 0 0 0 0 1 device=DIODE T 46700 44400 5 10 0 0 0 0 1 footprint=DO-35 } T 47500 44200 9 10 1 0 0 0 1 4x 220n N 41200 45400 42400 45400 4 N 47300 44100 49300 44100 4 N 45500 44100 45500 44200 4 N 46400 44100 46400 44200 4 N 47300 44100 47300 44200 4 N 44600 44100 44600 44200 4 C 42400 45600 1 180 1 opa.sym { T 42600 43300 5 10 0 0 180 6 1 device=DUAL_OPAMP T 42600 43500 5 10 0 0 180 6 1 footprint=DIL 14 300 T 42600 43100 5 10 0 0 180 6 1 symversion=0.2 } N 43400 44700 43400 45800 4 N 42400 44700 43400 44700 4 C 47100 42700 1 180 0 opa.sym { T 46900 40400 5 10 0 0 180 0 1 device=DUAL_OPAMP T 46900 40600 5 10 0 0 180 0 1 footprint=DIL 14 300 T 46900 40200 5 10 0 0 180 0 1 symversion=0.2 } C 47100 42400 1 0 0 resistor.sym { T 47400 42800 5 10 0 0 0 0 1 device=RESISTOR T 47700 42600 5 10 0 1 90 0 1 refdes=R? T 47100 42400 5 10 0 1 0 0 1 footprint=R025DOUBLE T 47300 42700 5 10 1 1 0 0 1 value=100K } C 47100 42000 1 0 0 resistor.sym { T 47400 42400 5 10 0 0 0 0 1 device=RESISTOR T 47700 42200 5 10 0 1 90 0 1 refdes=R? T 47100 42000 5 10 0 1 0 0 1 footprint=R025DOUBLE T 47300 41800 5 10 1 1 0 0 1 value=100K } N 48000 42500 48000 44100 4 N 48000 42100 48400 42100 4 N 48400 42100 48400 45200 4 C 46100 41500 1 0 0 resistor.sym { T 46400 41900 5 10 0 0 0 0 1 device=RESISTOR T 46700 41700 5 10 0 1 90 0 1 refdes=R? T 46100 41500 5 10 0 1 0 0 1 footprint=R025DOUBLE T 46300 41800 5 10 1 1 0 0 1 value=100K } N 45900 41600 45900 42300 4 C 47000 43300 1 180 0 resistor.sym { T 46700 42900 5 10 0 0 180 0 1 device=RESISTOR T 46400 43100 5 10 0 1 270 0 1 refdes=R? T 47000 43300 5 10 0 1 180 0 1 footprint=R025DOUBLE T 46800 43500 5 10 1 1 180 0 1 value=100K } N 42400 42600 42400 43900 4 N 42400 44300 42400 45000 4 N 47100 42500 47100 43200 4 N 47000 41600 47100 41600 4 N 47100 41600 47100 42100 4 N 43300 43400 43400 43400 4 N 47100 43200 47000 43200 4 C 43400 45700 1 0 0 output-1.sym { T 43600 46000 5 10 1 1 0 0 1 device=VG } C 45000 43300 1 180 1 input-1.sym { T 45000 43500 5 10 1 1 180 6 1 device=VG } N 43400 44100 43700 44100 4 N 43400 45200 43700 45200 4 N 45800 43200 46100 43200 4 C 44500 43000 1 180 0 opa.sym { T 44300 40700 5 10 0 0 180 0 1 device=DUAL_OPAMP T 44300 40900 5 10 0 0 180 0 1 footprint=DIL 14 300 T 44300 40500 5 10 0 0 180 0 1 symversion=0.2 } C 46000 42300 1 90 0 pot.sym { T 45100 43100 5 10 0 0 90 0 1 device=VARIABLE_RESISTOR T 45700 42700 5 10 1 1 180 0 1 refdes=R_RES } N 45900 42300 46100 42300 4 N 45900 41600 46100 41600 4 N 44500 42800 45400 42800 4 N 43300 42600 43500 42600 4 N 44500 42400 44500 41900 4 N 44500 41900 43500 41900 4 N 43500 41900 43500 42600 4 T 41000 49300 9 10 1 0 0 0 4 Virtual Ground VG at 4.1V : Room for signal + 4 diode drops + keep EIDAC transistors out of saturation Diff amp removes common mode in output due to DC diode drop. Total diode drop ranges 2V-3V over 3-4 decade bias current range. C 50400 49500 1 0 0 resistor.sym { T 50700 49900 5 10 0 1 0 0 1 device=RESISTOR T 51000 49700 5 10 0 1 90 0 1 refdes=R? T 50400 49500 5 10 0 1 0 0 1 footprint=R025DOUBLE T 50600 49800 5 10 0 1 0 0 1 value=100K } C 51500 48700 1 90 0 cap-mylar.sym { T 50800 48900 5 10 0 0 90 0 1 device=CAPACITOR T 51000 48900 5 10 0 1 90 0 1 refdes=C? T 50600 48900 5 10 0 0 90 0 1 symversion=0.1 } C 50400 48600 1 0 0 resistor.sym { T 50700 49000 5 10 0 1 0 0 1 device=RESISTOR T 51000 48800 5 10 0 1 90 0 1 refdes=R? T 50400 48600 5 10 0 1 0 0 1 footprint=R025DOUBLE T 50600 48900 5 10 0 1 0 0 1 value=100K } C 51300 49500 1 0 0 resistor.sym { T 51600 49900 5 10 0 1 0 0 1 device=RESISTOR T 51900 49700 5 10 0 1 90 0 1 refdes=R? T 51300 49500 5 10 0 1 0 0 1 footprint=R025DOUBLE T 51500 49800 5 10 0 1 0 0 1 value=100K } C 52400 48700 1 90 0 cap-mylar.sym { T 51700 48900 5 10 0 0 90 0 1 device=CAPACITOR T 51900 48900 5 10 0 1 90 0 1 refdes=C? T 51500 48900 5 10 0 0 90 0 1 symversion=0.1 } C 51300 48600 1 0 0 resistor.sym { T 51600 49000 5 10 0 1 0 0 1 device=RESISTOR T 51900 48800 5 10 0 1 90 0 1 refdes=R? T 51300 48600 5 10 0 1 0 0 1 footprint=R025DOUBLE T 51500 48900 5 10 0 1 0 0 1 value=100K } C 52200 49500 1 0 0 resistor.sym { T 52500 49900 5 10 0 1 0 0 1 device=RESISTOR T 52800 49700 5 10 0 1 90 0 1 refdes=R? T 52200 49500 5 10 0 1 0 0 1 footprint=R025DOUBLE T 52400 49800 5 10 0 1 0 0 1 value=100K } C 53300 48700 1 90 0 cap-mylar.sym { T 52600 48900 5 10 0 0 90 0 1 device=CAPACITOR T 52800 48900 5 10 0 1 90 0 1 refdes=C? T 52400 48900 5 10 0 0 90 0 1 symversion=0.1 } C 52200 48600 1 0 0 resistor.sym { T 52500 49000 5 10 0 1 0 0 1 device=RESISTOR T 52800 48800 5 10 0 1 90 0 1 refdes=R? T 52200 48600 5 10 0 1 0 0 1 footprint=R025DOUBLE T 52400 48900 5 10 0 1 0 0 1 value=100K } C 53100 49500 1 0 0 resistor.sym { T 53400 49900 5 10 0 1 0 0 1 device=RESISTOR T 53700 49700 5 10 0 1 90 0 1 refdes=R? T 53100 49500 5 10 0 1 0 0 1 footprint=R025DOUBLE T 53300 49800 5 10 0 1 0 0 1 value=100K } C 54200 48700 1 90 0 cap-mylar.sym { T 53500 48900 5 10 0 0 90 0 1 device=CAPACITOR T 54400 49100 5 10 1 1 180 0 1 refdes=C T 53300 48900 5 10 0 0 90 0 1 symversion=0.1 } C 53100 48600 1 0 0 resistor.sym { T 53400 49000 5 10 0 1 0 0 1 device=RESISTOR T 53700 48800 5 10 0 1 90 0 1 refdes=R? T 53100 48600 5 10 0 1 0 0 1 footprint=R025DOUBLE T 53300 48900 5 10 0 1 0 0 1 value=100K } C 54000 49500 1 0 0 output-1.sym { T 54900 49500 5 10 1 1 0 0 1 device=V_OUT- } C 54000 48600 1 0 0 output-1.sym { T 54900 48600 5 10 1 1 0 0 1 device=V_OUT+ } C 49600 48800 1 180 1 input-1.sym { T 49100 48800 5 10 1 1 180 6 1 device=V_IN } C 50300 49300 1 0 0 gnd.sym B 48900 46000 7900 4800 3 0 0 0 -1 -1 0 -1 -1 -1 -1 -1 T 49300 50000 9 10 1 0 0 0 3 DIODE LADDER SMALL SIGNAL V_IN driven from low-impedance source V_OUT+ , V_OUT- drive high impedance diff amp T 49300 47800 9 10 1 0 0 0 3 Lifting two inputs to V_IN/2 gives a symmetric circuit. The caps can then be split into 2 caps in series with middle at ground potential. The bottom half of that is: C 50300 47400 1 0 0 resistor.sym { T 50600 47800 5 10 0 1 0 0 1 device=RESISTOR T 50900 47600 5 10 0 1 90 0 1 refdes=R? T 50300 47400 5 10 0 1 0 0 1 footprint=R025DOUBLE T 50500 47700 5 10 0 1 0 0 1 value=100K } C 51400 46600 1 90 0 cap-mylar.sym { T 50700 46800 5 10 0 0 90 0 1 device=CAPACITOR T 50900 46800 5 10 0 1 90 0 1 refdes=C? T 50500 46800 5 10 0 0 90 0 1 symversion=0.1 } C 51200 47400 1 0 0 resistor.sym { T 51500 47800 5 10 0 1 0 0 1 device=RESISTOR T 51800 47600 5 10 0 1 90 0 1 refdes=R? T 51200 47400 5 10 0 1 0 0 1 footprint=R025DOUBLE T 51400 47700 5 10 0 1 0 0 1 value=100K } C 52300 46600 1 90 0 cap-mylar.sym { T 51600 46800 5 10 0 0 90 0 1 device=CAPACITOR T 51800 46800 5 10 0 1 90 0 1 refdes=C? T 51400 46800 5 10 0 0 90 0 1 symversion=0.1 } C 52100 47400 1 0 0 resistor.sym { T 52400 47800 5 10 0 1 0 0 1 device=RESISTOR T 52700 47600 5 10 0 1 90 0 1 refdes=R? T 52100 47400 5 10 0 1 0 0 1 footprint=R025DOUBLE T 52300 47700 5 10 0 1 0 0 1 value=100K } C 53200 46600 1 90 0 cap-mylar.sym { T 52500 46800 5 10 0 0 90 0 1 device=CAPACITOR T 52700 46800 5 10 0 1 90 0 1 refdes=C? T 52300 46800 5 10 0 0 90 0 1 symversion=0.1 } C 53000 47400 1 0 0 resistor.sym { T 53300 47800 5 10 0 1 0 0 1 device=RESISTOR T 53600 47600 5 10 0 1 90 0 1 refdes=R? T 53000 47400 5 10 0 1 0 0 1 footprint=R025DOUBLE T 53200 47700 5 10 0 1 0 0 1 value=100K } C 54100 46600 1 90 0 cap-mylar.sym { T 53400 46800 5 10 0 0 90 0 1 device=CAPACITOR T 54000 46800 5 10 1 1 0 0 1 refdes=2C T 53200 46800 5 10 0 0 90 0 1 symversion=0.1 } C 53900 47400 1 0 0 output-1.sym { T 54800 47400 5 10 1 1 0 0 1 device=(V_OUT+ - V_OUT-)/2 } C 49600 47600 1 180 1 input-1.sym { T 49000 47600 5 10 1 1 180 6 1 device=V_IN/2 } N 50400 47500 50300 47500 4 C 51100 46300 1 0 0 gnd.sym C 52000 46300 1 0 0 gnd.sym C 52900 46300 1 0 0 gnd.sym C 53800 46300 1 0 0 gnd.sym