LT1797 applicaTions inForMaTion Distortion There are two main contributors to distortion in op amps: typically 96dB. When the LT1797 switches between input output crossover distortion as the output transitions from stages there is significant nonlinearity in the CMRR. Lower sourcing to sinking current and distortion caused by non- load resistance increases the output crossover distortion, linear common mode rejection. If the op amp is operating but has no effect on the input stage transition distortion. in the inverting mode, there is no common mode induced For lowest distortion the LT1797 should be operated single distortion. If the op amp is operating in the PNP input stage supply, with the output always sourcing current and with (input is not within 1.3V of V+), the CMRR is very good, the input voltage swing between ground and (V+ – 1.3V). See the Typical Performance Characteristic curves. I1 Q18 Q17 R1 R2 1/2 SUPPLY Q15 Q16 Q19 BIAS QB1 I7 C2 Q13 Q14 R5 –IN Q1 Q2 Q9 Q10 D1 D2 I2 I3 R6 +IN R7 R8 +1 +1 CM OUT Q3 Q4 I4 I5 Q7 Q8 Q11 Q12 C1 Q5 Q6 Q20 R3 R4 I6 1797 F01 Figure 1. Simplified Schematic 1797fc For more information www.linear.com/LT1797 9
