Other Parts Discussed in Thread: ADS8881, , THS4551, THS2630
Hi TI expert ,
I am designing a MFB band pass filter for 18bit ADC( ADS8881), the center frequency of BPF is 1kHz, Q = 4, gain = 1, pass bandwidth = 250Hz, stop bandwidth = 2500Hz,
stop band attenuation = -20dB, Butterworth to achieve minimum ripple. My final goal is to get datasheet performance(SNR, THD) of ADS8881, so I need to design the band pass filter with lowest noise and lowest distortion, do a lot of search in the TI forum, then THS4551 or THS4541 will be the best choice for the filter amplifier. From the datasheet, THS4541 should have a better noise performance than THS4551, but when I do the simulation with TINA, THS4541 give me more output noise then THS4551, please help on that, why this happening? Did I do something wrong here?
If possible, Could you help to recommend a better BPF design for this goal? My sine wave source is good, but not good enough to achieve ADS8881 datasheet performance, so I need a low noise & low distortion BPF to get the best ADC performance.
Here is the TINA simulation file for both of these amplifiers.