1. Gain, Gain-Bandwidth Product, Maximum Frequency or Bandwidth
2. -3 dB Bandwidth, Cutoff frequencies, Frequency response
3. Class of Amplification, Power Efficiency, Static Power Consumption
4. Open or Closed-Feedback and Stability
5. DC offset, input bias, input and output impedance, drift
6. Slew rate, SNR, SNDR, NF, THD
In addition to SkyHigh's reply I mention 2 notes one for signal amplifiers and one for power amplifiers:
1.dynamic range, which is the maximum level of inputs that the amplifier works in it's linear range and almost depends on the first transistors( BJT or FET).This property is very important for low level signal amplifiers.
2.efficiency,which is the ration of maximum output power to DC power.This property depends on the disipation of transistors in amplifier .Class B is better than A and swiching Classes are best.
tks for your reply . but there are a lot of problems that I don't kown. can you tell me them using AD811 for a example. (I just kown 'gain' ,Slew rate). I don't kown what are current-feedback operational amplifier and voltage-feedback operational.