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The application of four operational amplifiers in LT6005

Hello, may I ask that I have been using LT6005CDHC recently, which is integrated with four operational amplifiers. My idea is to use one of them to design a transimpedance amplifier, and the remaining three operational amplifiers to design a 6-order low-pass filter. However, compared with the separate TIA and low-pass filter, the output signal quality is not ideal and the noise is very loud. May I ask why?