* MAX4238 MACROMODEL * ------------------------------ * Revision 0, 9/2003 * ------------------------------ * The MAX4238 family of op amps are low noise, low drift, ultra high precision amplifiers * that offer near zero DC offset and drift. These devices operate from 2.7V to 5.5V supply * and feature Rail to Rail outputs. An active-low shutdown mode decreases supply current * to 0.1uA. * ------------------------------ * Connections * 1 = SHDN * 2 = IN- * 3 = IN+ * 4 = GND * 5 = NC * 6 = OUT * 7 = VCC * 8 = NC ***************** *$ .SUBCKT MAX4238 1 2 3 4 6 7 XAMP1 7 4 3 2 6 1 MAX4238_S .ENDS ***************** .SUBCKT MAX4238_S 10 18 17 15 75 54 * 10 = VCC * 18 = VEE * 17 = IN+ * 15 = IN- * 75 = OUT * 54 = SHDN ***************** *INPUT STAGE VS1 10 11 0V GBIAS 11 12 52 20 4.66U CBIAS 12 18 0.1P M1 13 16 12 11 MOSFET M2 14 15 12 11 MOSFET DBIAS 18 12 DA VOS 19 16 0.1U *INPUT OFFSET VOLTAGE ERDC 19 17 111 20 1 RD1 13 18 10K RD2 14 18 10K C1 13 14 5.2P *SECOND ORDER POLE AT 1.5MHz DIN1 16 11 DX *INPUT VOLTAGE LIMITING DIODES DIN2 18 16 DX DIN3 15 11 DX DIN4 18 15 DX FSUP 18 10 VS1 1 *TO COMPENSATE SUPPLY CURRENT ECHK 199 20 13 14 1 ************** *INPUT BIAS CURRENT IBIAS1 12 16 1P IBIAS2 12 15 2P *BIAS CURRENT OFFSET ************************************************** *GAIN STAGE GA 21 20 14 13 3.1623M RO1 21 20 10K GB 22 20 21 20 1 RO2 22 20 1MEG EF 23 20 22 20 1 *VOLTAGE FOLLOWER FOR FEEDBACK RLF 23 20 10MEG CC 21 23 418P *OPEN LOOP POLE AT 31.62mHz EG1 20 18 10 18 0.5 GCP 22 20 110 20 10 *CMRR AND PSRR AC RESPONSE ***************** *DEVICE ENABLE REN2 10 54 1G *EN INPUT IS NODE 54 IEN1 18 54 100NA DEN3 54 10 DX EEN2 55 20 54 18 1 REN4 55 58 120K DEN4 56 55 DA REN3 58 56 60K CEN 58 20 23P ****** EEN1 48 20 58 20 1 *VCC - VEN EHYST1 48 49 52 20 -1.4 VEN1 49 50 2.2V REN1 50 51 5K VIS2 20 51 0V ******* FEN1 52 20 VIS2 4 DEN2 20 52 DA DEN1 52 53 DA CL2 52 20 100P RLEN 52 20 1MEG VLIM2 53 20 1V RDLY 52 57 40K CDLY 57 20 200P ***************** DVL1 22 33 DA *VOLTAGE LIMITING VMIN1 59 33 0V DVL2 34 22 DA VMIN2 34 60 0V ELIM2 59 61 10 18 0.5 ELIM1 63 60 10 18 0.5 ECOMP2 62 20 65 66 1 ECOMP1 64 20 65 66 1 HCOMP2 62 61 VIS3 16.4 HCOMP1 64 63 VIS3 16.4 ***************** EOUT 65 20 22 20 1 *VOLTAGE FOLLOWER ROUT1 65 66 5 *OPEN LOOP OUTPUT RESISTANCE VIS3 66 67 0V RLOAD 75 20 100MEG ***************** *CURRENT LIMIT DSC1 67 68 DA DSC2 69 67 DA DSC3 69 70 DA DSC4 70 68 DA ISC1 68 69 40MA *LIMITING CURRENT T0 40MA RSC 68 69 10MEG ***************** *DISABLE SWITCH MEN1 71 72 70 10 MOSFETP MEN2 71 73 70 18 MOSFETN EEN3 70 72 52 20 10 EEN4 73 70 52 20 10 RSHUNT 70 71 10MEG VIS5 71 75 0V ***************** *SUPPLY CURRENT *BIAS CURRENT DSUP 18 10 DB ISUP 10 18 0.143UA *BIAS CURRENT GSUP 10 18 52 20 600U *LOAD CURRENT FSUP1 20 77 VIS5 1 CSUP 77 20 1P DSUP1 20 77 DB DSUP2 77 78 DB VIS4 78 20 0V FSUP2 10 18 VIS4 1 ***************** *PSRR DC AND AC ESUP1 79 20 10 18 1 CPA 79 115 16P CPB 115 116 16P CPC 116 117 16P CPD 117 118 16P RPA 115 20 10K RPB 116 20 10K RPC 117 20 10K RPD 118 20 10K GPSRR1 110 20 118 20 0.1 *AC GPSRR2 20 111 79 20 100N *DC -140dB RRDC 111 20 1 RRAC 110 20 1 *RRAC1 122 20 1 ***************** *CMRR DC AND AC ECM1 81 20 12 18 1 GCM2 20 111 81 20 100N *DC -140dB ***************** *MAX COMMON MODE INPUT VCC-1.3V DIL 12 83 DA RIL 83 84 50 VIL 85 84 1.0V EIL 85 18 10 18 1 ***************** *MINIMUM SUPPLY VOLTAGE SET AT 2.7 DVL3 18 12 DA DVL4 12 86 DA FVL 86 18 VIS6 1 VVL 87 18 2.7V VIS6 87 88 0V DVL5 88 89 DA RVL 89 90 300 EVL1 90 18 10 18 1 ************************************************** .MODEL MOSFETN NMOS(VTO=5 KP=88E-2) .MODEL MOSFETP PMOS(VTO=-5 KP=88E-2) .MODEL MOSFET PMOS(VTO=-0.2 KP=21.56E-4) .MODEL DA D(N=0.1M) .MODEL DX D(IS=100E-14 RS=0.5k) .MODEL DB D(IS=100E-14) ************************************************** .ENDS *$